AP Biology 2007 (Period 1&2)

Science Debate 2008

2008-02-22T10:13:00.000-08:00

Have you seen this:
http://sciencedebate2008.com

Would be great if you students got to see this.
==========================================

Universities, corporations and a host of individuals are calling for a debate with all four of the remaining presidential candidates discussing critical scientific issues that impact everything from the environment to the economy.

Sciencedebate2008.com, formed by two Hollywood screenwriters who had time to mull science recently while on strike, is an effort aimed at thrusting technology into the limelight.

One of the initiative's founders, Shawn Otto, said yesterday more than 17,000 American universities and the editors of nearly every major science publication in the nation have added their names to the Web site, encouraging the presidential hopefuls to debate key scientific issues.

"This is a nonprofit organization we set up to raise the profile of science and technology in our national political diaglogue," Otto said, adding that his initiative is now being co-sponsored by the National Academy of Sciences, the Institute of Medicine, the National Academy of Engineering, the Council on Competitiveness and the American Association for the Advancement of Science.

Yesterday, John Podesta, chief of staff for former President Bill Clinton, posted a video statement on YouTube echoing that science remains one of the nation's primary areas of focus. He called for a presidential debate "in charting a path forward on national security, on energy and climate change policy, really on the core fundamentals of our economic policy."

Otto said it would be "really fabulous" to see Democrats and Republicans on the same stage debating issues in science.

"All of us believe that almost every major policy challenge that the next president will face revolves around questions of science and technology," Otto said, referring to signers of his initiative.

"Ever since World War II, America has been leading in science and technology, and science and engineering have driven half of our economic growth."

But in the not-too-distant future, he added, 90 percent of all scientists will be living in Asia, causing a major "shift in intellectual capital."

James McCarthy on Science Debate 2008

John Porter on Science Debate 2008

Francesca Grifo on Science Debate 2008

Immune system

2008-02-12T18:44:00.000-08:00

3rd line of defense in your immune system

the last say in the immune systems defense is lymphocytes.

B cells and T cells recognize the foreign antigens. B cells get their name because they're matured in the bonemarrow.
T cells get their name because....

So moving away from that...
B cells floating in blood and lymph check out antigens(the protein coat to identify cells) at random.
should they happen to find some one they dont recognize, or better yet DO recognize as a hazard, they release
the antibodies.
Antibodies stick to the foreign cell to slow it down acting as shackles.... but more acurately like...

thats right...net guns

Once officially "netted" T cells call in the macrophages, and from there... its good game pathogen

B cells keep memeory of every antigen, so when it comes around again they know just how to fight back.

HORMONES

2008-02-12T17:29:00.000-08:00

Action Of Protein Hormones

on a signal-transduction pathway

First, the protein hormone is reconized by the receptor and binds to it (signal). Then a secondary messenger system, and transduction (to transfer a message from one form to another) occurs. And finally a response from a cell is produced.

This all takes place on a signal transduction pathway. This requires the use of energy and different messengers.

Action Of Epinephrine

(adrenalin)

First the epinephrine binds to receptor than a message is sent to second receptor. It goes through a secondary messenger system and eventually sends a response to release glucose to blood.

2° Messenger System

has benefits
A 2° messenger system is a chain reaction, allowing for amplication and a very fast response.

Maintaing Homeostasis
negative feedback

When a specific body condition gets to high, a glad is signaled to produce a hormone, which lowers body condition. When condition gets too low, gland is signaled to produce a different hormone to raise body coondidtion.

An example of this is the Nervous System controlling Body temperature. When body temperature gets too high, brain sends nerve signals which make body sweat and dilate survace blood vessels, lowering temperature. When body temperature gets too low, brain sends nerve signals to make body shiver and constrict surface blood vessels bringing temperature back up.

Better to breathe like a camel than look like one...

2008-02-07T14:32:00.000-08:00

Dear Journal,

Today, at like, 6 o'clock or something, I was too lazy to get up, but I did anyway. So when I was up, I took a shower and got ready. Then I think I went to school. In Bio we learned some stuff I think, but I mostly just dazed off and thought about things. Like why peanutbutter is sticky, and how awesome it sounds when you rub two pickle slices together, 'cos you get that tiny little squeeky noise...

Anyway.

If I had paid attention (or stayed awake for that matter) in Bio, I probably would've learned about antibodies and stuff. But I was too lazy. So let's see, what do I know about antibodies.....

They're Greeeeeat!

Why you ask?
READ ON!

Without our immune system we would be.....

Why?
Our B-Cells, which produce antibodies, test every cell they come in contact with. They check its antigens, which are really like name tags. Antigens are present on EVERY SINGLE CELL....even our own! But, luckily for us, our antigens are recognized by our B-cells as our own, and they do not trigger a response.

However, when a B-cell comes in contact with a foreign invader, such as a virus, B-cells speed into action! Now there are two things that can happen:

1) If the virus has been in the body at an earlier time, the B-cells would already have made antibodies. If this is so, then the B-cells recognize the virus as an intruder, clone 1000's of B-cells with antibodies, and plasma cells release antibodies. Antibodies are "handcuffs" and they slow down the intruder for an easier destruction! How exciting!

2) If this virus is a new intruder, B-cells make antibodies for that specific virus or invader. At this rate, it takes a long time (about 10-17 days) to dispose of the virus, but antibodies have now been made, and are ready to leap like a crouching tiger!

YIKES! I feel bad for the virus the next time it tries to get in your blood!

Then of course, after these antibodies are made, the next time the virus enters, our immune system is able to recognize it so much quicker, and therefore destroy it uber quickly.

This graph shows the concentration of antibodies before and during the first exposure to the virus, and before, during, and after the second exposure. As you can clearly see, after the first attack, antibodies are at the ready, and can recognize, locate, and destroy the unwanted invader quickly and efficiently. This truly was an amazing adaptation.

Now comes the ever popular question: How can we produce millions of antibody proteins if we only have a few thousand genes?

AHA! The answer seems difficult. But behold! It is not!

If we had four decks of cards, and we picked 1 card from each at random, we could end up with a total of 7,311,616 possible combinations. That's alot of combos!

But seriously...

There are more than 52 selections to pick from in humans. We are only able to make these millions of combinations by picking different parts of DNA and putting them together. This process allows for an enormous amount of options.

And now......

For the moment you've all been waiting for.......

It's finally time......

Don't hold your breath......

Here it comes.....

OH NO!!!!

It's..................

Vaccinations???? Oh well.

Vaccinations are really weakened or even dead forms of viruses. They cant harm us as much as the actual virus because, well, they're weak! These weak viruses allow our immune system to make antibodies specifically for the virus, without making us feel the full effects of the disease.
Vaccines are most successful against viral diseases.

Does this school look familiar? It should! This is Jonas E. Salk Middle School, and it was named after the man who invented the vaccination.

Here he is.

That's right. Jonas E. Salk.

Although Salk did not win a nobel prize for medicine, he was a brilliant man, and should be acknowleged for his findings, and specifically for his ending of the polio epidemic.

So if that is Active Immunity, then what is Passive Immunity??

The best example of passive immunity is when infants obtain antibodies from their mothers breast milk. This is specifically referred to as Maternal Immunity. Antibodies pass from the mother to the infant, and because the two are exposed to the same virus's and invaders, these antibodies are especially helpful.

Another way to obtain passive immunity is through injection. In these cases, antibodies are injected into the bloodstream. However, this type of immunity only lasts for a very short time. Hence the term, "Passive Immunity."

And what about the virus's that sneak into the body cells?
Well now, thats a different story for another journal entry.
Until next time.

Sean

Immune System

2008-02-05T18:24:00.000-08:00

Immune/Lymphatic System

Avenues of Attacks

- Any opening in the body is a point of entry:

- digestive system

- respitory system

- urogenital tract

- breaks in skin

- Routes of attack: how foreginers move around the body once in
- circulatory system

- lymph system

- Why an immune system?

- Attack from outside

- organiams like to feed upon us due to our containement of fats,

lipids, and proteins

- we must protect our cells because cell wall protection has

been traded for mobility

- animals must defend themselves against invaders

- Viruses: HIV, flu, colds etc.

- Bacteria: Pneumonia, meningitis, etc.

- Protistis: amoeba

- Attack from the inside

- when own cells let go of the restrictions of their genitically programed jobs

- ex: cancer cells

- Animals evolved a lymph system

- The production and transprt of leukcytes traps foreign invaders

- Development of Red and White blood cells
- 3 Lines of Defense

- 1st line: barriers

- external defense

- skin and mucus membranes

- 2nd line: non- specific patrol
- broad internal innate defense; attempts to keep everything out

- attacks anything not recognized

- leukocytes = phagocytic WBC

- 3rd line: immune system

- specific aquired immunity

- inherit the ability but aquire defense

- lymphocytes (trained cells) and antibodies

- B cells

- make antibodies

- T Cells

- 1st line: External Defense

- Physical and Chemical Defenses

- non-specific defenders

- External Barrier

- epithelial cells and mucus membranes

- skin

- respiratory system

- digestive system

- uro-genital tract
-Chemical Barriers on epithelium

- Skin and mucous membrane secretions

- acidity in sweat

- tears act as a washing action

- mucus traps microbes

- saliva contains an anti-bacterial

- acidity in the stomach

- anti-microbial proteins

- lysozyme enzyme

- digests bacterial cell walls
- 2nd line: Internal, broad range patrol

- Innate, general defense

- Rapid response

- Patrolling cells and proteins

- they attack invaders that penetrate body's outer barriers

- leukocytes

- phagocytic (engulfing) white blood cells

- Complement system

-Anti-microbial proteins- in blood & plasma

- Inflammatory response

- Leukcoytes: Phagocytic WBC's

- attracted by chemical

- signals released by damaged cells

- enter infected tissue, engulf and ingest microves

- lysosomes

- Neutrophils

- most abundant WBC's

- Macrophages

- "big eater"- long lived

- take pieces of digested invaded and they destroy their cell with it as an alarm

- Natural Killer Cells

- destroy virus-infected cells and cancer cells

- Destroying cells gone bad

- Natural Killer Cells perforate cells
- release perforin protein

- insert into membrane of target cells

- forms pore allowing fluid to flow into cell

- no longer selectively permeable

- cell ruptures

- in flow of liquids into cell causing cell the rupture- apoptosis

- Anti- microbial protein

- 20 proteins circulating in blood plasma

- attacks bacterial and fungal cells

- form a membrane attack complexstamines and prostaglandins

- perforate target cell

- apoptosis

- cell lysis

- Inflammatory Response

- damage to tissue triggers local non-specific inflammatory response `

- release histamines and prostaglandins

- cappilaries dilate - more permeable - all in an attempt to "plug the leak"

- increase blood supply

- delivers WBC, RBC, platelets clotting factors

- fight pathogens

- clot formation

- Fever
-When a local response is not enough

-systemic response to infection

- activated macrophages release interleukin-1

- triggers hypothalamus in brian to readjust body thermostat to raise body temperature (fever)

- higher temperature helps defense

- inhibits bacterial growth

- stimulates phagocytosis

- speeds up repair of tissues

- causes liver and spleen to store iron, reducing blood iron levels

- bacteria need large amounts of iron to grow

Circulation in Animals

2008-01-14T21:50:00.000-08:00

What truly is the point of Circulation? Why build such a complex system stretching through out the entire body? Below these questions shall be answered.

Exchange of Materials

The true point of the Circulatory system is to exchange, and transport materials from cells, and to cell, and to other parts of the body. This includes:
Needs

Oxygen
nutrients
Sugars, proteins, etc.
Water
Protective Agents(White blood cells, antibodies, platelet's, etc.)
Hormones

Wastes

Carbon Dioxide
Urea
Water

Multicellular Animals need these essential materials, and to get ride of waste, but unlike unicellular organisms cant obtain it through diffusion alone, for this reason they need the Circulatory system, this network or highway for transport.

Types of Circulatory Systems

All Animals have some characteristics in common for their mode of circulation. The all contain blood vessels, a heart, and some type of fluid to transport materials in (blood for humans).
Open

Invertebrates( insects, mollusk, anthropods) contain an open circulatory system which means they have no separation between blood, and interstitial fluid, instead they have hemolymph. This is a fluid that runs through their entire body touching the organs, and giving them nutrients.

Closed

Invertebrates( Octopie, earthworms, squid ) have separate blood from interstitial fluid. They have at least one heart, complex blood vessels, exchanging of materials between the blood, and the outside interstitial fluid.
Vertebrates( humans, clownfish , macaques ) also have a closed circulatory system. They have seperate blood from interstitial fluid, and complex blood vessels. The characteristics of vertebrates differ greatly through different evolutionary stages.

Evolution of heart chambers

The number of heart chambers differs greatly ranging from 2-4 in vertebrates. Having more chambers was a selective value because it is more efficient system, separating oxygen rich, and oxygen poor blood giving cells a fresh supply of concentrated oxygen. Having only 2 chambers, like a fish mixes the oxygen rich, and oxygen poor blood giving less overall oxygen to the cells. Since mammals, and birds are endothermic they also had a selective force to heave 4 chambered hearts so they could supply they needs of making heat by getting the supplies around faster, and with what is truely needed.

Blood Vessels

There are 3 main types of Blood Vessels found in the circulatory system of vertebrates.
Arteries

Arteries are the blood vessels that carry blood away from the heart.
They are thicker than veins so that they can be able to make high pressure pumping of blood. Since it is pumping blood to the body it ne eds pressure to force the blood to move to the different parts of the body.
Has a narrow diameter to help keep high pressure within the vessels.

Veins

Veins are the blood vessels that carry blood towards, or back to the heart.
Low pressure so that skeletal muscle contractions are able to move the blood flow more easily towards the heart.
Wider diameter so there is less pressure.
Thinner walls for less pressure.
Valves in some of the larger veins help to direct blood flow by opening and closing leading blood to the heart.

Capillaries

Very small blood vessels that branch from the larger veins, and arteries but connected to the arterioles, and venules.
Very thin, only one layer of cells, endothelium.
Very permeable from thinness allowing the diffusions of molecules such as oxygen, and urea, and making for the connection for the transp ort of materials between cells, and the circulatory system.

The blood flow in capillaries can be controlled through the pre-capillary sphincters. They can retrict or allow blood flow through capillaries by either closing, or opening up. This is useful for when certain body parts are in need of blood, open, an d to close them when the part is in no need of blood.
The capillaries also exchange fluids, and solutes into the interstitial fluid through "bulk flow" or having a high pressure gradient. The interstitial fluid also flows into the capillaries through osmosis.

Lymphatic System

The Lymph system very much like the circulatory system and is parallel with it. The Lymph system is an open system, and helps collect, and return interstitial fluid to the blood. It also helps the bodies immune system greatly. It aids in the production of lymphocytes, and anti-bodies, also transporting these throughout the whole body as well as white blood cells to aid wherever they are needed. The system drops its load into the circulatory system near the vena cava, and right atrium.

Mammalian heart

The heart of your typical mammal is very similar, as we saw in the cow heart dissection. It consists of Pulmonary arteries, and veins which pump blood to and out the capillaries of the lungs, and the Aorta which is an artery that pumps blood throughout the body. The Coronary arteries give a supply of blood to the heart giving fresh supplies of oxygen. Many times this is blocked by buildup of cholesterol, and can cause a heart attack which can lead to needing bypass surgery, in which a alternate pathway from the aorta is made to the heart so it can get its supply of blood and not fail to pump.
The heart is made of up 4 chambers, the left and right Ventricle, and the left and right Atrium. These chambers are separated by four valves, made up of connective tissue that prevent back flow keeping the blood pumping in the direction it is needed. The sounds "Lub" and "dub" are produced from these valves closing, and opening. The Atrioventricular valves (AV) are between the atrium, and ventricle, and prevents blood from flowing in the atria when the ventricles contract. The Semi lunar valves are between the ventricles, and arteries and prevent blood from flowing into the ventricles from the arteries when the heart is relaxing.
A Cardiac cycle is one complete cycle of the hear pumping. This is when the heart contracts, and pumps, then relaxes and refills with blood. The contraction phase is called systole, and the relaxation phase is called diastole. This is the way someones blood pressure is measured to check if they have hypertension. The top number is systolic pumping(a higher number), and the bottom number is the diastolic pumping(lower number).

Jan. 10

2008-01-14T19:05:00.000-08:00

Here are some key points we should have absorbed today

Animals get thier food by
-Filter (suspension) feeding
-Substrate feeding
-Fluid feeding
-Bulk feeding

-Animals cannot make: elements; N, P, K, Fe, Na, Ca and NAD, FAD so they must take it in through food

peristalsis-push food along by rhythmic waves of smooth muscle contraction in walls of the digestive system.

Sphincters-muscular ring-like valves, regulate the passage of material between sections of digestive system.

Accessory glands- salivary glands, pancreas, liver, and gall bladder secrete digestive juices such as enzymes and fluid.

Stomach-stores foos, disinfects food, performs chemical digestion

Ulcers-caused by a bacteria overload in your stomach called helicobacter pylori cured with antibiotics.

Small intestine-chemical digestion, absorption through lining
-duodenum=most digestion
-jejunum=absorption of nutrients and water
-ileum=absorption of nutrients and water

-the small intestine is lined with villi and microvilli
the villi increase the surface area to absorb materials into the blood

large iontestine-re-absorb water
the large intestine is inhabited by countless bacteria including E. coli
the bacteria produce necessary vitamins for survival and help with digestion

Rectum-eliminate feces (extracellular waste) this waste has never been absorbed into the bloodstream.

Digestion continued...

2008-01-08T21:11:00.000-08:00

The liver is responsible for the production of bile. Bile is a chemical made from dead red blood cells. Bile breaks down the fats that we eat.
After bile is produced it is stored in the gall bladder, it is released in the presence of fats

in order to break them down.

THIS IS ONLY ONE OF MANY FUNCTIONS THAT THE LIVER IS RESPONSIBLE FOR SUCH AS THE POISON CONTROL OF THE BODY

The pancreas breaks down carbohydrates and further breaks down proteins. The peptidases that are made by the pancreas are called

Trypsin, Chymotrypsin, and carboxypeptidase.these are then changes to their inactive form which are trypsinogen,chimotrypsin, and procarboxypeptidase. This change occurs in order to protect the pancreas from getting digested. When needed tripsinogen is changed back into tripsen by the small intestine then tripsen activates the other enzymes to change.

The small intestine is the major organ of digestion and absorption.

The small intestine is over 6m and has a alot of surface area for absorption due to the thousands of villi against its lining.

The small intestine is made of 3 parts the Duodenum where most digestion occurs.

Jejunam and Ileum where absorption of nutrients and water occur.

The nutrients from the food are absorbed through the capillary walls which are only one cell thick

What ever the body cannot put to use gets sent to the large intestine. Products such as cellulose which or body cannot digest is sent here. The large intestine has a bunch of good bacteria

that prduce vitimans and help digest cellulose.

The liver also re-absorbs water back into the blood stream so we dont dehydrate.

The last section of the large intestine is the rectum which eliminates the pheces and undigested materials from the body

and lastly you end up with...

Digestion

2008-01-08T18:48:00.000-08:00

Chemical digestion occurs once food has

entered the stomach from the esophagus.

Most people believe that the stomach's function is digestion. The true function of the stomach is to store food, the stomach makes it possible for us to eat meals through out the day. The stomach also disinfect anything that is not suppose to come down with the food. HCl make the disinfection possible, with a ph of 2 it kills bacteria and begins to break apart food.

The enzyme that digests protein is called pepsin

Luckily we have mucus that is secreted to protect

our stomach lining. If we didn't then the pepsin would digest our stomachs since the stomach is made out of protein.

A Gastric ulcer is when ones stomach begins to digest itself. Gastric Ulcers are caused by a bacterial infection known as Helicobacter Pylori. Gastric Ulcers are cured with weeks of antibiotics.

While all of this is occuring the food

stays put in the stomach due to 2

sphincters. One is called the cardiac sphincter

which keeps the food from going up.

The 2nd is called the pyloric sphincter which keeps the food from going down.

The liver is responsible for the production of bile.

Bile is a chemical made from dead red blood cells.

Bile breaks down the fats that we eat.

After bile is produced it is stored in the gall bladder, it is released in the presence of fats in order to break them down.

PPPPP

Nutrition

2008-01-07T16:02:00.000-08:00

All animals need to consume food to live. Oxygen and some sort of food source are needed for animals to grow. The raw materials are gained through eating and the oxygen is used in respiration which makes the energy needed for the synthesis of those raw materials into larger molecules.

Animals get their food in four different ways-

~Bulk Feeding~

Bulk Feeding is cosuming large concentrated portions of your food source.

~Fluid Feeding~

This is when organisms get theier nutrients from a liquid like blood or sap.

~Substrate Feeding~

Substrate feeding is when the organism spends part of its' life living in its food source.

~Filter Feeding~

This mode envloves the intake of huge amounts of your food source straight out of the environment.

Your digestive system is basically a really long tube where food products are broken down and the needed parts are absorbed the rest excreted as extracellular waste because it never actually entered your cells.

Food is pushed through the digestive track by involuntary muscle contractions known as peristalsis. According to Paige this is like an utter.

Digestion starts with Ingestion

Swallowing starts off the process the epiglottis (cartilage flap) closes securing itslef over your trachea preventing food from "going down the wrong pipe". Waves of muscle push the food towards the stomach which is where we finished our lesson.

2007-12-20T20:24:00.000-08:00

Stage One: Glycolysis

Whats the point? To make ATP!!

Glycolysis literally means splitting two sugars. This name is appropriate because this is exactly what happens during the first stage of cellular respiration; glucose is digested.

Glycolysis is an ancient process. Bacteria where the first to do this.
Glycolysis is where energy transfer first evolved. It is a transfer of energy from organic molecules to inorganic molecules.

But its inefficient!
A working muscle use millions of molecules of ATP a second. Glycolysis only makes 2 ATP's.

Who were the first to do glucolysis?
Prokaryotes!
Billions of years ago there was no free oxygen in the atmosphere.Oxygen had to be captured by organic molecules such as glucose.

All cells undergo glycolysis!

The Reaction:
1. Begins with one glucose molecule (six carbons)
2.Fructose-16bP takes off Phosphate from 2 ATP and place a phosphate on either side of the glucose.
3. The carbons pull apart due to oxygen's high electronegativity. This forms 2 pyruvates or two 3 carbon molecules.
4. 4 ATP's and 2NADH's (piggy bank) are formed. However 2ATP's were used to start the process (the match).
5. Net: 2ATP's and 2NADH's

What is the point? TO MAKE ATP

2007-12-18T13:25:00.000-08:00

Guys today we learned how our body makes energy. Well what is the point? POINT IS TO MAKE ATP.

Energy is really important because we need it to reproduce, synthesis, to move, to grow, and to regulate our temperature.

The work of life is done by energy coupling, which is using exergonic reactions to fuel the endergonic reactions.

Whatever we eat, we have to digest or break it down to simpler molecules that can enter our cells and they can eventually use them. We need something in our body which helps to pass this energy around. And the best answer is ATP!!!.

ATP stands for Adenosine Triphospate. Where do we see Adenine before? In RNA and DNA.

ATP has three phosphate group attaches to an adenine and ribose.

First we start out with adenosine, and ribose, and when we attach one phosphate to this, this is named AMP or adenosine monophosphate, which means one phospate.

Then when we add another phosphate group to the adenine, ribose, and previous phosphate group, we make adenosine diphosphate, meaning two phosphates.

Third, we make ATP by adding another phosphate group, thus making adenine triphosphate.

Adding all these phosphates requires A LOT of energy and I mean A LOT.

BUT, the question is why does it require so much energy? Well lets see an example, remember when we hold magnets together towards the same poles, WHAT DO THEY DO? THEY REPEL EACH OTHER. This is the same reason for the phosphates. The phosphates are highly negative and do not want to be with another molecule which is also highly negative. This is due to the oxygen. AND WHAT IS OXYGEN? HIGHLY ELECTRONEGATIVE.

The phosphate bonds make ATP an excellent energy donor.

HOW DOES ATP TRANSFER ENERGY?

The word is PHOSPHORYLATION. This is when phosphate is taken off of ATP. This released phosphate can be transferred to other molecules. And enzyme that helps in this is kinase.

Building polymers from monomer is a perfect example of phosphorylation. The bonds holding the monomer have to be destabilized in order to make it a polymer.

The first step of cellular respiration is glycolysis. This is the breaking of glucose to make ATP. First the bonds of glucose have to be destabilized in order for it to be broken down. And whenever a carbon to carbon bond is broken, energy is released!!

Activators and Inhibitors

2007-12-18T13:11:00.000-08:00

Hey guys, yesterday we finished our lecture on enzymes by talking about how activators and inhibitors affect enzyme activity. We also talked about allosteric regulation, cooperativity, metabolic pathways and how these pathways are efficient for the cell.

Enzyme activity is sensitive to the presence of specific substances that bind to the enzyme and cause conformational change in the enzyme (conformational change is the change in the shape of the molecule, in this case the active site of the enzyme). Through these substances, a cell is able to regulate which of its enzymes are active and which are inactive at a particular time. This allows the cell to increase its efficiency and to control changes in its characteristic during development.

The first type of substance that we will talk about is an activator which binds to the active site of the enzyme and increases the activity of the enzyme. Enzyme function is often assisted by additional chemical components known as cofactors and coenzymes.

Cofactors are non-protein, small inorganic compounds and ions. Inorganic compounds are compounds that do not have carbon to carbon bonds. These small molecules are usually metals and bind within the enzyme molecule. For example zinc is used by some enzymes to draw electrons away form their position in covalent bonds in the substrate, making the bonds less stable and easier to break the bonds between the substrate. *Remember glucose, it is stable and needs something to disrupt the bond well here the metals in the enzyme draw the electrons away from the substrate molecules, disrupting the bonds between the substrate.*

Coenzymes are nonprotein, organic molecules which are molecules that have carbon to carbon bonds. These molecules bind temporarily or permanently to the enzyme near its active site. Many vitamins are parts of coenzymes. In numerous ozidation reduction reactions that are catalyzed by enzymes, the electrons pass in pairs from the active site of the enzyme ot a coenzyme that serves as the electron acceptor. The coenzyme then trasfers the electrons to a different enzyme, which releases them to the substrates in another reaction. These electrons have energy with them. One of the most important coenzymes is the hydrogen acceptor nicotinamide adenine dinucleotide (NAD+).

Those were activators but there are also substances that bind to he an enzyme and decreases the activity of the enzyme and these substances are called inhibitors. There are four types of inhibition: competitive inhibition, noncompetitive inhibition, irreversible inhibition, and feedback inhibition.

competitive inhibitor

Competitive inhibitors compete with the substrate for the same active site, displacing a percentage of substrate molecules from the enzymes. One example of this type of inhibitors is the medicine penicillin. Penicillin blocks the enzyme bacteria use to build their cell wall. To overcome competitive inhibition is to increase the substrate concentration because if there is higher concentration of substrates than the inhibitor, then there would be more collisions between the enzyme and the substrate; the enzyme will more frequently collide with the substrate.

noncompetitive inhibitor

Noncompetitive inhibitors bind to the enzyme in a location other than the active site, changing the shape of the active site of the enzyme making the enzyme unable to bind to the substrate. Most noncompetitive inhibitors bind to a specific portion fo the enzyme called an allosteric site. A substance that binds ot an allosteric site and reduces enzyme activity si called an allosteric inhibitor. When this substance binds to this site, it causes a conformational change in the active site which is no longer a functional binding site.

Irreversible inhibitors are the same thing as competive and noncompetitive inhibitors, however irreversible inhibitors are inhibitors that permanently bind to the enzyme. So competitor would bind permanently to the active site while the allosteric (noncompetive) will permanently bind to the allosteric site of the enzyme.

Before we can talk about the last inhibitor, it is important if we get the understanding about metabolic pathways. Organisms contain thousands fo different kinds of enzymes that catalyze a wide variety fo reactions. Many of these reactions in a cell occur in sequences called metabolic or biochemical pathways. In such pathways, the product of one reaction becomes the substrate for the next reaction. Metabolic pathways creates organization and efficiency amongst the cell.

Now we can talk about feedback inhibition. Feedback inhibition is a process where the end production of a biochemical pathway acts as an inhibitor of an early reaction. Not only is it unnecessary to synthesize a compound when plenty is already present, but doing so would waste energy and raw materials. It is therefore advantageous for a cell to temporarily shut down biochemical pathways when their products are not needed and this is when feedback inhibition comes in. The end product of the pathway binds to an allosteric site on the enzyme that catalyzes the first reaction in the pathway, causing conformational change and preventing the enzyme from functioning properly.

For a better understanding of the biochemical pathway and the feedback inhibition please go to http://www.explorebiology.com/apbiology/resources/ and go under enzymes and metabolism and click on the second biochemical pathway animations.

Allosteric regulation is conformational changes by regulatory molecules like inhibitors that keep enzyme in an inactive form and activators that keep the enzyme in an active form. Cooperativity is when a substrate acts as an activator because it causes a conformational change in the enzyme and this makes it easier for other substrates to bind to the enzyme.

Well I hope I had helped you out.

Metabolism and Enzymes

2007-12-11T18:21:00.000-08:00

Metabolism and Enzymes!

Chemical Reactions:

Metabolism is a chemical reaction of life. Bonds forming and breaking between molecules are both involved.

Forming bonds are known as dehydration synthesis, and anabolic reactions. This synthesis requires an enzyme and the release of H2O, while bringing two molecules together.

This diagram shows the dehydration synthesis of sucrose. An enzyme combines Glucose and Frustose, while releasing H2O, to form the compound Sucrose.

Breaking bonds is known as hydrolysis, digestion and catabolic reastions. Breaking of bonds requires a different enzyme, and H2O, to breakdown a compound into two molecules.

This diagram shows Hydrolysis. An enzyme, as well as H2O, is used breakdown the compound into two seperate molecules.

Energy is present is both breaking and forming of bonds. Some reactions release energy, for example hydrolysis, the digesting of polymers. When reactions release energy, it is known as Exergonic.

While some reactions release energy, others require energy. Dehydration Synthesis, the building of polymers, is an example of a chemical reaction requiring energy. These chemical reactions are known as Endergonic.

Activation Energy:

Since reactions don't just happen spontaneously, since covalent bonds are stable, energy is needed to initiate a chemical reaction. This energy is known as Activation Energy. Sometimes the amount of energy needed to destabilize a bond is too much for life. An example of this is lighting a match to burn a piece of paper, like Ms. Foglia did in class.

When there is too much activaton energy in a reaction, a catalyst can be added to reduce the amount of activation energy used to start a reaction. For a cell to reduce energy, an enzyme is added. The enzyme acts as a catalyst for the cell. As Philmore said "Call in the ENZYMES!"

The Nervous System

2007-12-05T19:29:00.000-08:00

Today in class we continued to learn about the NERVOUS SYSTEM.

Voltage-Gated Channels

Changes in charge across the membrane causes ion channels to open and close.

In response to depolarization, Na+ channels open quickly and close slowly. While K+ channels open slowly and close slowly in response to depolarization.A neuron has to re-set itself after every reaction for the next reaction. Na+ is moved back out while K+ is moved back in. One protein pumps both potassium and sodium out with the use of energy because both are moving against the concentration gradients.
The nerve re-sets itself by pumping 3 Na+ out and 2 K+ in, which is not an equal exchange. Active transport proteins in the membrane are responsible for pumping Na+ out and K+ in. These proteins require a great deal of energy, or ATP.
Action Potential Graph

1. Resting potential- voltage-gated ion channels are closed but some K+ pass through 2. Threshold Potential- an action potential is produced
3. Depolarization- voltage-gated sodium channels open and allow Na+ to diffuse
4. Na+ channels close and K+ channels open
5. Repolarization- diffusion of K+ out of the axon; resets charge gradient
6. Undershoot- K+ channels start to close

Myelin Sheath

Axons are lined with Schwann cells which act as insulators to ensure that signals go far. Signals travel from node to node to reach their destination. A loss of signal can cause Multiple Sclerosis, when the immune system attacks myelin sheath.

Due to the gaps between neurons, impulses have to jump the synapse as quickly as possible to get to other cells. A chemical charge is needed to jump the gaps, so chemicals stored in the vesicles release neurotransmitters. The diffusion of chemicals across the synpases carry the chemcial signal across the synapse.

Neurotransmitters:

-Acetylcholine: help in the contraction of muscles, transmit signals to skeletal muscle

-Epinephrine & Norepinephrine: fight or flight response

-Dopamine: help in getting people out of comas but too much of it can cause schizophrenia

-Serotonin: affects sleep, learning and attention

Our next sherpa will be Ashley Scavo.

Regulating The Internal Environment Part 2

2007-12-04T14:13:00.000-08:00

~Maintaining Homeostasis~

Homesostasis in the body is maintained through a series of different actions trigured by different internal and external stimuli.

The Negative Feedback Loop is one of the most essential actions. It starts with a stimulis, sensors within the body monitor these changes and immdeiately send information to the corresponding intergrating sensor such as an organ or a gland. From there chemicals are released to return the condition to its normal state. Once the response is complete sensors stop sending information and the chemical is stopped, thus allowing the system to enter a state of rest until it must perform its' function again.

An example of this is the action your body goes through when you are threatened or excited. The pituitary gland releases a hormone that causes your adrenal glands to release adrenaline which allows your body to perform basic functions at a heightened level. Adrenaline effects your heartrate and general awareness, giving you abilities that you don't normally have.

The endocrine system also plays a large role in regulating homeostasis. Blood pressure and osmolarity are regulalted by the endocrine system, specifically the brain and kidneys. The pituitary gland monitors these conditions and when something happens to the levels of either osmolarity or BP then action is immediately taken.

-If blood osmolarity rises to high meaning it becomes hypertonic the pituitary gland trigures the release of an anti-diuretic hormone a.k.a. ADH. This increases the permeability of the collecting ducks in the kidneys allowing for increased water absorption. This dilutes the blood bringing it back down to a more stable level.

-If blood pressure drops too low renin is released which removes part of the protein angiotensinogen already found in the blood exposing its' reaction site allowing it to cause the kidneys to release aldosterone. This causes increased water and salt absorption replacing missing components of the blood so pressure is restored.

The other key system to maintaining homeostasis is the

Nervous System.

The most important cell of the nervous system is the neuron. The neurons in the body work very similar to a line of dominoes. A signal starts the reaction like knocking over the first one. A wave is then sent through each single cell until it reaches its predetermined destination. The only way it can occur again is if you reset the axons in a neuron or the lines of dominoes.

Nerve cell live in a sea of charged ions. Ions with negative charges (anions) are found more within the cell, and ions with positive charges (cations) are more common outside the cell. When a nerve is stimulated Sodium channels in the cell membrane open allowing the diffusion of positively charged ions into the cell. At this point the charge on the cell is reversed. Following the first wave another wave of channels is opened this time allowing cations to move out of the cell causing the repolarization of the nerve cell. This is the way messages are sent from anywhere in your body to your brain within milliseconds. After all channels have been closed again and the cell is stabalized it is ready to fire again.

Monday Dec. 3

2007-12-03T19:37:00.000-08:00

Mammalian Kidney

-The 2 kidneys have 1,000,000 nephrons each inside them.
-The Nephron filter out urea and other solutes
-the blood leading to the kidneys is from the inferior vena cava
-an animals blood pressure forces the blood into the glomerulus forcing out the liquid and small solutes in the blood.
-too high of blood pressure in this region is hypertension which causes kidney damage
-the glomerulus is a ball of capilaries surrounded by the bowmans capsule which collects the liquid from the blood
-the bowmans capsule then leads to the loop of henle.
-the descending loop of henle reabsorbs h2o
-the ascending loop reabsorbs salts and pumps cl- that it followed by na+ due to unlike charge attraction.
-the collecting duct reabsorbs h2o and urea is passed through the bladder

-diffusion is used in the nephron whenever possible, water is never moved by active transport because it is unnecessary energy use

Whats left in the blood if all the liquid is squeezed out in the glomerulus?
-cells and proteins are too big to fit diffuse through the capillaries

Whats excreted?
-highly concentrated urea, excess h2o, excess solutes (salts and glucose)

Regulating The Internal enviorment

2007-12-02T22:30:00.000-08:00

Homeostasis is the tendency of the body to seek and maintain a condition of balance within its internal environment, even when faced with external changes. this includes cell growth ion balance temperature blood sugar levels energy production cell growth water balance and nutrients.

There are conformers and Regulators. Conformors change their internal conditions to what ever the external enviorment is. An example of a conformors are snakes.

Regulators maintain their interal conditions constant. Such as as body temperature, in humans the normal body temperatur is 98.6

Osmoregulation is the balance of fluids in order to maintain homeostasis.

Their are three conditions that are involved. For each of these conditions the kidney works in different ways.

Hypertonic is a solution with higher solute concentration (higher osmotic pressure) than another so water wants to move in.

Hypotonic is a solution with lower solute concentration (lower osmotic pressure) than another so water wants to move out of

Isotonic is solution with the same solute concentration (same osmotic pressure) as another no net movement of water.

fish that live in fresh water take up salt from the enviorment. Water will flow into the fish and the fish will excrete a low concentration urine to get rid of all of the extra water.

As for fish that live in salt water they tend to lose water and gain salt. They excrete salt from their gills. Water organisms excreteamonia they do not transform it.

Land animals need to conserve water and may need to conserve salt since they live in a dry enviormnent. When we digest foods we create waste products . when we consume nucleic acids we create amonia. Amonia is toxic an carcinogenic it is easily put into cells(soluble). Land animals change amonia into urea to make it less toxic and terrestrial. Uric acid is Eliminated in a pastelike form through the cloaca (mixed with feces) in birds and reptiles. Land animals must excrete it quickly, the longer that amonia is in our body the more problems we can encounter

Egg animals conserve as much water as possible. They create uric acid which is less soluble. it is not a liquid waste. To make something less soluble you make it bigger.

The kidney maintains homeostasis in the body by

removing waste products from the body
removing drugs form the body
balance the body's fluids
releases hormones that regulate blood pressure
produce an active form of vitamin D that promotes strong, healthy bones
control the production of red blood cells.

The kidney works in 4 steps

Filtration- body fluids are collected (blood).

Water and soluble material are removed.

Reabsorption- reabsorb needed substances back in the blood

Secretion- pump out unwanted substances to urine.

Excretion-remove excess substances and toxins from body.

Movement Across the cell membrane

2007-11-29T17:35:00.000-08:00

So in class we learned about diffusion, and the channels within the cell membrane. The definition of Diffusion is the movement of high to low concentration.

CELL MEMBRANE
The cell membrane is a buffer zone between the internal cell, and the outside of the cell. Cells need to get material in, and wastes out. The cell membrane allows for things such as food, carbohydrates, sugars, proteins, amino acids, lipids, salts, oxygen, and water. The cells need to get wastes such as ammonia, salts, carbon dioxide, water, extra sugar, and other products out of the cell. They are stern. Stern but fair. They must be tough.

As you can see the membrane surrounds the cell, and makes sure only necessary materials get in and out.
DIFFUSION THROUGH A PHOSPHOLIPID BILAYER
Since the middle of the phospholipid bilayer is non polar, only other non-polar molecules can get through, such as Fats and other lipids. Water, other polar molecules, ions, and large molecules cant get though. It's like a hip Hollywood party. Only the coolest celebrities get access, Fats, and other lipids. Polar molecules, ions, and large molecules aren't "cool" enough to get into this party.
CHANNELS THROUGH CELL MEMBRANE
Protein Channels make a membrane semi-permeable. Certain channels allow certain membranes across into the cell.

FACILITATED DIFFUSION
This is just simple diffusion through a membrane channel. When a channel and a molecule are right for each other, the channel moves a specific molecule across the channel into the cell. This doesn't require any energy.
ACTIVE TRANSPORT
Sometimes high to low concentration just isn't the cool thing to do. Therefore molecules must succumb to peer pressure and go against the concentration gradient. The protein pump, changes its shape to transport the molecules from one side to another. What does this cost you may ask? ATP. Energy. you know.LARGE MOLECULES
Large molecules need loving to. You know what I'm saying. They can move in through vesicles, and vacuoles. There is endocytosis, and exocytosis.

Endocytosis has two parts.
-Phagocytosis is "cellular eating". I mean cells get hungry too. It is a process where cells absorb material ( molecules such as proteins) from the outside by engulfing it with the cell membrane. -pinocytosis is "cellular drinking". is a form of endocytosis in which small particles are brought into the cell suspended within small vesicles which subsequently fuse with lysosomes to hydrolyze, or to break down, the particles.
Exocytosis is the process in which a cell directs secretory vesicles to the cell membrane.
that should be sufficient

REGULATING THE INTERNAL ENVIORNMENT

2007-11-29T14:19:00.001-08:00

Regulating the Internal Environment

Conforemers vs. Regulators
There are two evolutionary paths for organisms, they can either regulate their internal enviornment or conform to their external environment. When organisms regulate thier internal enviornment they are able to maintain a relatively constant internal condition, when they conform they allow their internal conditions to fluctuate along with
any external changes.

Water Balance and Nitrogenous Waster Removal
As there was a change from unicellular to mutlicellular organisms the syestems within animal had to evolve in order to support all multicellular life.One can see this through the respitory system, digestive system and circulatroy system all working together. Through entry ways foods and other materials are entered into the body but at the same time both extra cellular waste and intrecellular waste are being removed. Another example is systems built inside larger cells. Becasue the cells have divided and therefor created a larger surface area the cells inside are not exposed to water and there for are not able to diffuse items into them, but becasue
these cells have systems that creates entry ways into them they are able to gain materials no matter what their location maybe.

Solving Exchange Problems
In order to over come the limitations of diffusion certain systems much have evolved.Exchange systemes are of use in distributing nutrients by the circulatory system and removing of wastes through the excrectory system.

Osmoregulation
We were also introduced to the beginnings of osmoregulation or the balancing of water.Osomoregulation is determined by where you live and the amount of water in your surronding areas.Organims found in fresh water will regulate their water systems differently then let say those found on land due to the amount and the type of water that is availible to them.

pardon the lack of pictures, but the system doesn't seem to be working in my favor today
and our next report will be delivered by Alex.
Enjoy! =)

Diffusion 101

2007-11-28T10:12:00.000-08:00

For the past few days we have learning the basics of diffusion.

But what is diffusion?

Diffusion refers to the process by which molecules intermingle as a result of their kinetc energy of random motion.

We having been trying to figure out why cells can not get infinetly large. This is because the rate of diffusion will always remain the same; therefore if the cell gets too big the middle out the cell with die because it will not get nutrients fast enough or waste out fast enough. In order words the surface area to violume ratio will work against the cell.

In the cell races lab, six teams compete to make the cell with the most mass and the smallest diffusion time. Congrats to Muskan's group for winning in our class!

In our labs we also tested to see what elements would diffuse across the cell membrane. We set up an experiment with one beakers. In the beaker we placed water and a tester and in the diffusion tube we placed water starch and glucose.

In conclusion we found that the tester, water, and glucose diffused in and out of the cell; however starch did not because the molecule was to big.

Starch looks like this:

or like this:

Theme 8: SCIENCE, TECHNOLOGY & SOCIETY

2007-11-21T09:38:00.000-08:00

Theme 8: SCIENCE, TECHNOLOGY & SOCIETY
Explanation: Scientific research often leads to technological advances that can have positive and/or negative impacts upon society as a whole.
Clarification: You would post here examples of how technological innovations have helped advance science whil ethose technolical accomplishments may have also had either beneficial or deleterious impacts on human society.

Theme 7: INTERDEPENDENCE IN NATURE

2007-11-21T09:34:00.000-08:00

Theme 7: INTERDEPENDENCE IN NATURE
Explanation: Living organisms rarely exist alone in nature.
Clarification: You would post here examples of how organisms must interact together to live successfully.

Theme 6: REGULATION

2007-11-21T09:27:00.000-08:00

Theme 6: REGULATION
Explanation: Everything from cells to organisms to ecosystems is in a state of dynamic balance that must be controlled by positive or negative feedback mechanisms.
Clarification: You would post here examples of how a dynamic equilibrium is maintained at different levels of life, from homesostatic control of cellular and body conditions to maintenance of population levels in ecosystems.

Theme 5: RELATIONSHIP OF STRUCTURE & FUNCTION

2007-11-21T09:13:00.000-08:00

Theme 5: RELATIONSHIP OF STRUCTURE & FUNCTION
Explanation: The structural levels from molecules to organisms ensure successful functioning in all living organisms and living systems.
Clarification: You would post here examples of structure-function relationships in living organisms. How specific molecules, organelles, cells, tissues, organs, and body structures are structured to support the functions that they perform. (Don't forget plants!)

Theme 4: CONTINUITY & CHANGE

2007-11-21T09:08:00.000-08:00

Theme 4: CONTINUITY & CHANGE
Explanation: All species tend to maintain themselves from generation to generation using the same genetic code. However, there are genetic mechanisms that lead to change over time, or evolution.
Clarification: You would post here examples of how organisms reproduce while maintaining the same genetic information from generation to generation AND also examples of how organisms reproduce while accumulating changes to their genetic information from generation to generation.

Theme 3: ENERGY TRANSFER

2007-11-21T09:04:00.000-08:00

Theme 3: ENERGY TRANSFER
Description: Energy is the capacity to do work. All living organisms are active (living) because of their abilities to link energy reactions to the biochemical reactions that take place within their cells.
Clarification: You would post here examples of how organisms are able to capture energy and utilize it to do the work that supports life.

Theme 2: EVOLUTION

2007-11-21T09:01:00.000-08:00

Theme 2: EVOLUTION
Description: Biological change of organisms that occurs over time. Which is driven by the process of natural selection. Evolution accounts for the diversity of life on Earth.
Clarification: You would post here examples of evolutionary change in populations of organisms that we have been able to observe or have evidence of.

Theme 1: SCIENCE AS A PROCESS

2007-11-21T08:59:00.001-08:00

SCIENCE AS A PROCESS
Description: Science is a way of knowing. It can involve a discovery process using inductive reasoning, or it can be a process of hypothesis testing.
Clarification: You would post here examples of how the scientific process has been used to develop our knowledge about how the biological world works.

Our Grand Tour of the Cell

2007-11-19T12:12:00.000-08:00

okay, so now that we're done with Biochemistry, we've moved on to learning about the cell and it's structure. So, let's get started.

The first thing we talked about today was the three types of cells. The three types of cells are prokaryotic, eukaryotic animal, and eukaryotic plant cells.

The main difference between prokaryotic cells and eukaryotic cells is that eukaryotic cells have organelles and are compartmentalized whil prokaryotic cells are not.

Why Organelles?

-Organelles are important because they are specialized structures that carry out specific functions. Also, they act as containers that separate different parts of the cell so they do not affect each other. If there was not this compartmentalization, then the environments of each organelle would mix with the others, and most of the organelles would be damaged and unable to perform their designated function. Lastly, organelles are important because the membranes serve as sites for chemical reactions to take place.

Jobs of Cells

-Cells have three basic jobs that they must do. First, they must build proteins. They need proteins because proteins control every function of the cell. Proteins are the things that actually create new cells from DNA. As fillmore said today, DNA gets the glory, but proteins do all the work. Second, cells need to make energy, or ATP. The cell needs this energy to do everyday processes and for growth. Third, the cell needs to build more cells for growth, repair, and reproduction.

Building Proteins

-There are many organelles involved in building proteins. The production of proteins starts at the nucleus, where DNA is changed into RNA for transport to the ribosomes in the endoplasmic reticulum. The ribosomes then use the RNA to make proteins, which are then transported from the ER to the golgi apparatus by a transport vesicle. The golgi apparatus pretty much acts like a little UPS truck. It basically figures out where the protein needs to go, and sends it there in another vesicle.

Making Energy

-Why do cells make energy? Cells make energy because they need power. Without it, the cell would not be able to perform many of its daily tasks. On a daily basis, cells need to take in and digest food, take in oxygen, make ATP, and remove waste.

Lysosomes

-Lysosomes are the "little stomach" of the cell. They digest macromolecules and old organelles in the cell to help keep it clean. Without them, the cell would keep accumulating waste with no way to get rid of it, and would eventually be filled with wastes and be unable to perform any life processes. This is why it becomes so fatal when lysosomes do not work properly. When your lysosomes do not function properly, you can develop a lysosomal storage disease. There are over 40 different kinds of this disease, the most common being tay-sachs disease and hunters disease. Most often, people with these diseases die young and do not live past the age of three. This is why the proper function of lysosomes is extremely important.

That's it for today, today's lesson will be continued tomorrow by Jess.

Nucleic Acids

2007-11-17T10:45:00.000-08:00

Hey guys. I know today was the happiest day for everyone because today we finally finished biochemistry. We are finally over with chemistry!!!!!!!!!!!!!!!!!!!!!!!!

Today we finished off biochemistry with Nucleic acids. Nucleic acids are the information storage devices of our cells. Not only do nucleic acids store information but they also transmit hereditary information to the next generations. Nucleic acids are able to serve as templates to produce precise copies of themselves, so that the information that specifies what an organism is can be copied and passed down to its descendants. The information that is being passed on between generations of organisms is the ability to produce the correct proteins. There are two varieties of nucleic acids that aid in the process passing on this information to the next generation: DNA and RNA. The DNA encodes the information that is used to assemble proteins while the cells use RNA to read the cell's DNA encoded information and direct the synthesis of proteins. The RNA then passes out into the rest of the cell, where it serves as a blueprint specifying a protein's amino acid sequence.

Nucleic acids are made out of monomers which are called nucleotides. There are three parts to nucleotides: a nitrogen base (C-N ring), pentose sugar (5C), and a phosphate group. The pentose sugar is different in both DNA and RNA in that RNA has ribose while DNA has deoxyribose which means without sugar. Now the phosphate group is highly electronegative because it has oxygen and is a charged particle. So nucleic acids are highly charged molecules making them hydrophilic and not fearing water. Now there are two types of nucleotides: purines and pyrimidines. Purines are large, double ring molecules found in both DNA and RNA. Purines are adenine and guanine. Pyrimidines are smaller, single-ring molecules and they are cytosine, thymine, and uracil.

Before we go on to the building of the polymer, we should talk a little about DNA and RNA. DNA is a double nucleotide chain in that the N bases bond in pairs across chains. The double chains in DNA wind around each other and create a double helix. RNA on the other hand is a single nucleotide chain in where the nitrogen base dangle offs and is not connected to another nitrogen base. DNA and RNA both contain adenine, guanine, and cytosine but DNA has thymine while RNA has uracil.

Now we should talk about the nucleic polymer. The backbone of the nucleic acids contains a sugar to phosphate bond. When new bases are added to the sugar of the previous bases, a phosphodiester bond forms between them. To made the bond we need the enzyme called DNA or RNA polymerase. The nitrogen bases hangs off the sugar-phosphate backbone and this is important because this allows us to make compliments from the nitrogen base that is exposed; allows us to have a template. Nucleotides bond between the DNA strands in specific pairings. A purine bonds with a pyrimidine and a hydrogen bond forms between them. Now there is a specific pairing in that adenine bonds to thymine in DNA or adenine bonds to uracil in RNA, and guanine bonds to cytosine. A 2 hydrogen bonds forms between adenine and thymine and a 3 hydrogen bond forms between guanine and cytosine. The hydrogen bonds between the nucleotides join the 2 strands together. Ratio of A-T::G-C affects the stability of the DNA molecule like in higher temperature there are more G-C than A-T because G-C contains and 3 hydrogen bond which is stronger than 2 bonds.

Well we are finally finished with biochemistry but we are not finished with sherpa reports and our next sherpa is Sarah.

"I did my homework and became who I am today because I did my homework." (yea right)

Protein's Cont'd

2007-11-16T17:15:00.000-08:00

Hey guys, well I know the structure of proteins is kind of difficult to learn, but I will try to do the best I can to help you guys understand this.

The primary structure is basically the order of amino acids in chains. Even a slight change in the amino acid can affect a protein's structure and then FUNCTION. One protein can determine the difference between sickle cell anemia and the normal red blood cells.

The secondary structure is local folding. This folds along short sections of polypeptide. They are hydrogen bonds between each R groups.

The dotted lines between the diagram are hydrogen bonds.

The tertiary structure is also known as whole molecule folding. This is determined by interactions between R groups. Hydrophobic bonds want to stay away from water so they cluster together so that the hydrophobic bonds are next to each other, clustered together. This is important in the structure of the the cell membrane. The hydrophobic tails basically face each other in a cell membrane, away from the water and cluster together, while the heads are hydrophylic and face the water. This forms a phospholipid bilayer.

The quaternary structure is when more than one polypeptide chain is joined together. However, it is important to note that not all proteins have subunits and more than one polypeptide. This polypeptide take different shapes and this then determines their functions. Its basically HYDROPHOBIC INTERACTIONS.

The unfolding of a protein has a fancy name for it called denaturing. When a protein unfolds, the tertiary structure, or 3' structure is disrupted. The pH, otherwise the acidity, is one of the factors. Another is salty environment, as well as temperature. Size doesn't matter, shape matters. Denaturing of proteins disrupts the H bonds, ionic bonds, and disulfide bridges. Ms. Foglia had boiled milk and added vinegar. Vinegar is an acid which disrupting the shape of the proteins. And believe it or not, it is the process of making cheese!!!

Proteins

2007-11-14T18:22:00.000-08:00

Proteins

The most important job of a cell is to make proteins. Proteins are made in the ribosomes of a cell. Protiens are used for almost anything. They have many different structures, with each different structure having a different function. They are also known as multipurpose molecules.

Some examples of proteins are keratin and collagen which makes up hair nails and skin.

Proteins are made of two structures monomers and polymers. Monomers are amino acids, and there are 20 different ones. Polymers are polypeptides. Proteins can be one or more polypeptide chains that are folded and bonded together. They are large and complex molecules.

The structure of amino acids have a central carbon, and amino acid groups. The carboxyl group are acids. The R group is a side chain. This is a variable group confers unique chemical properties of the amino acids.

Nonpolar amino acids are nonpolar and hydrophobic. Nonpolar meaning there are carbons in it. Hydrophobic means that it does not like water so it tends to try and push the water away. On the other hand amino acids can be polar and hydrophilic. By polar it means that it has a nitrogen in it. Hydrophilic means that it likes water and wants to be in or as near as possible to water as it can. They are polar and hydrophilic because they fold in order to make a protein.

Sulfur containing amino acids allow a link between sulfers and amino acids to be created called disulfide bridges. It smells like rotten eggs or permed hair.

Peptide bonda are building proteins that link the NH2 of one amino acid to COOH of another. Part of the buildin proteins are polypeptide chains that involve N-terminus= NH2 end and the C- terminus which ends in a COOH.

One of the four levels of structure is primary (1 degree) stucture pattern. The DNA of the gene decides the amino acid sequence and even a slight change in the sequence can make it a change in the protein's stucture and funtion. The perfect example of this is Sickle Cell Anemia, where the structure of the cell of hemoglobin goes from a 'doughnut' shape to one that looks like a 'sickle' or 'cresant moon'.

Carbohydrates !

2007-11-12T18:43:00.001-08:00

Ahhh yes Per. 1&2
It is time to unveil my most devious plan everr, preparations A through G were complete failures... but now it is time to initiate.... Preparation H.

On Friday we had the wonderful opportunity of learning all about my good friend, the standard Carbohydrate. Now mah boy "carbohydrate" means a "hydrate of carbon.” Back in college him hydrogen and oxygen were near inseparable with a 1:2:1 ratio..

"I’d say they were pretty tight"

Now the general formula of carbohydrate Cx (H2O) y - x and y may or may not be equal and range in value from 3 to 12 or more.

For example glucose is: C6 (H2O) 6 or is more commonly written, C6H12O6.The chemistry of carbohydrates most closely resembles that of alcohol, aldehyde, and ketone functional groups. The chemistry of carbohydrates is complicated by the fact that there is a functional group (alcohol) on almost every carbon. In addition, the carbohydrate may exist in either a straight chain or a ring structure.
A major part of the carbon cycle occurs as carbon dioxide is converted to carbohydrates through photosynthesis. Carbohydrates are utilized by animals and humans in metabolism to produce energy and other compounds.

Carbohydrate Functions:
Carbohydrates are initially synthesized in plants from a complex series of reactions involving photosynthesis.
-Store energy in the form of starch (photosynthesis in plants) or glycogen (in animals and humans).
-Provide energy through metabolism pathways and cycles.
-Supply carbon for synthesis of other compounds.
-Form structural components in cells and tissues.

Photosynthesis:
Is a complex series of reactions carried out by algae, phytoplankton, and the leaves in plants, which utilize the energy from the sun. The simplified version of this chemical reaction is to utilize carbon dioxide molecules from the air and water molecules and the energy from the sun to produce a simple sugar such as glucose and oxygen molecules as a by product. The simple sugars are then converted into other molecules such as starch, fats, proteins, enzymes, and DNA/RNA i.e. all of the other molecules in living plants. All of the "matter/stuff" of a plant ultimately is produced as a result of this photosynthesis reaction.

Metabolism:
Metabolism occurs in animals and humans after the ingestion of organic plant or animal foods. In the cells a series of complex reactions occurs with oxygen to convert for example glucose sugar into the products of carbon dioxide and water and ENERGY. This reaction is also carried out by bacteria in the decomposition/decay of waste materials on land and in the water.
Combustion occurs when any organic material is reacted in the presence of oxygen to give off the products of carbon dioxide and water and ENERGY. The organic material can be any fossil fuel such as natural gas oil, or coal. Other organic materials that combust are wood, paper, plastics, and cloth.

The whole purpose of both processes is to convert chemical energy into other forms of energy such as heat.

The monomers of carbohydrates are called monosaccharides and are also called simple sugars. They are usually ring-like and are composed of five or six carbons. They are either a polyhydroxy aldehyde or a polyhydroxy ketone, which means they have more than one hydroxide group (-OH) and one carbonyl group (C=O). Some popular monosaccharides are glucose, fructose, and galactose.However, some very important carbohydrates are composed of thousands of monomers and are called polysaccharides. Here are the main important polysaccharides:- starch: Plants store their energy as starch using photosynthesis. We eat plants, breaking down the starch into its monomers and putting it to good use.- cellulose: The cell walls around plants are composed of cellulose. Cellulose is a very important structural component of plants and it's what makes them snap when you rip them apart. Err, I mean - they provide support for the plant.- glycogen: Animals store energy as glycogen. It's stored in the liver.

A carbonyl group is a functional group composed of a carbon atom double bonded to an oxygen atom : C=O.

An aldehyde is an organic compound containing a terminal carbonyl group. This functional group which consists of a carbon atom which is bonded to a hydrogen atom and double bonded to an oxygen atom (chemical formula O=CH-), is called the aldehyde group.

A ketone (pronounced as key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group. A ketone can be generally represented by the formula:
R1(CO)R2.

Cellulose:
The major component in the rigid cell walls in plants is cellulose
(Fat B@$tard also seems to be composed of a similar substance)

Cellulose is a linear polysaccharide polymer with many glucose monosaccharide units. The acetal linkage is beta which makes it different from starch. This peculiar difference in acetal linkages results in a major difference in digestibility in humans. Humans are unable to digest cellulose because the appropriate enzymes to breakdown the beta acetal linkages are lacking. Indigestible cellulose is the fiber which aids in the smooth working of the intestinal tract.
Animals such as cows, horses, sheep, goats, and termites have symbiotic bacteria in the intestinal tract. These symbiotic bacteria possess the necessary enzymes to digest cellulose in the GI tract. They have the required enzymes for the breakdown or hydrolysis of the cellulose; the animals do not, not even termites, have the correct enzymes. No vertebrate can digest cellulose directly.

Compare Cellulose & Starch Structures:
Cellulose: Beta glucose is the monomer unit in cellulose. As a result of the bond angles in the beta acetal linkage, cellulose is mostly a linear chain.
Starch: Alpha glucose is the monomer unit in starch. As a result of the bond angles in the alpha acetal linkage, starch-amylose actually forms a spiral much like a coiled spring.

I leave you with the mugshots of two alleged carb jackers

(Known only as Moonshine the Hippie & Lil Red) previously taken into custody for posession of carbs with intent to distribute.

Although uneasy on the eys I urge to look beyond the mundane and horror to identify these criminals for whoever does... would most worthy of tomorrows sherpa report!

Chemistry of Carbon

2007-11-08T13:02:00.000-08:00

Today we learned about Carbon, which just reinforces the idea presented in Paiges post about how terrible Chemistry really is.

- All life is built on carbon. Cells are made up of 72% water, 25% carbon, and 3% Salt.

That is us, mostly made of water.
- And thats the carbon we're made of!

First off theres the BIG 4: Carbohydrates, Lipids, Proteins, and Nucleic Acids

Carbon atoms are very versatile building blocks because they equally share electrons with hydrogen. They have 4 stable covalent bonds.

Hydrocarbons are combinations of carbon and hydrogen. They are non-polar, hydrophobic (fear of water), stable, and are gases at room temperatures. They are gases because there is no close attraction between the molecules so therefore they stay far apart.

Isomers: are molecules with the same molecular formula but different structures or shapes.

*Form affects function!*
Small structural differences can create important functional significance. For example the amino acid alanine has an L-version and a D-version. They are mirror images of each other and are called stereoisomers. In medicine, only the L-version is active and this is important to know because of tragic effects such as in the case of Thalidomide. It was intended to reduce morning sickness but instead caused severe birth defects in limb development.

Diversity of Molecules :
Substitute other atoms or groups around the carbon. Ethane can become Ethanol (alcohol) when an H is replaced by a hydroxyl group (-OH). This change makes ethane non-polar, and ethanol polar, and ethane a gas while ethanol is a liquid. Below is an example of what ethanol can do to you and your belly.

Functional Groups are parts of organic molecules that are involved in chemical reactions. These groups are hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, and phosphate. These groups are all the difference in the case of female and males. They have the same carbon skeleton but different functional groups are attached and one becomes estrogen while the other is testosterone.

Macromolecules- smaller organic molecules join together to form larger molecules. The big 4 are the major classes of macromolecules.
-Polymers are long molecules built by linking repeating building blocks in a chain.
-Monomers are small building blocks.

Building Polymers

Dehydration (Condensation) Synthesis: a water molecule is removed
- one monomer donates OH- and another donates H+, these two combine to form H2O

Breaking down Polymers

Digestion (Hydrolysis) - use H2O to break down polymers. The water is split into H+ and OH-
Requires Enzymes

Carbon are the building blocks of life, so I guess I dont hate them after all<3 Tom and the lunchbox are the next sherpas.

2007-11-07T18:09:00.001-08:00

the Good, the Bad, and the BIOCHEMISTRY!
We all took chemistry over the past two years and it was terrible and its back.

We spent the entire period studying the properties of water which are super important because all life occurs in water, inside and outside of the cell.

COHESION AND ADHESION
COHESION: H bonding between water molecules

-just like Tom and his girl pictured above, water likes to stick together. That’s why we can suck it up through a straw.

- water has an extremely high surface tension, so that’s why not a lot of organisms can walk on it, except for Jesus and insects like the water strider of course. The strider’s impact on the water is less than H2O’s surface tension so they don’t sink.

ADHESION: H bonding with H2O and other substances
Ex: capillary action, meniscus, water on paper towel

SO LETS APPLY THESE TO REAL LIFE: trees.
Trees are built on cohesion and adhesion. The stomates on the tree’s leaves open to allow water molecules to evaporate. As one molecule leaves the leaf, it pulls another water molecule along, and it continues.

-polarity makes H2O a stellar solvent because water molecules surround positive and negative ions.
-hydrophilic and polar: DISSOLVE IN WATER
-hydrophobic and non-polar: SEPERATES FROM WATER (no attraction)

ICE ICE BABYYY.

All substances are denser as a solid right? NOPE, not water. Ice floats!
-At 4 degrees Celsius, water is at its densest.

So why is floating ice so important in real living things?
When lakes freeze over, the surface ice insulates the water below it making it possible for fish and other organisms to live through winter. Floating Ice also attributes to the cycling of nutrients.

FOGLIA ICE TIP OF THE DAY:
Make sure you always mix your drinks at the bar,

this way you never have to drink a weak mix, and you save cash!

SPECIFIC HEAT: how much energy is required to heat a substance
-water has a very high specific heat. It takes more to heat up and cool down water than anything else.
-specific heat’s important because H2O moderates all temperatures on earth.
-areas surrounded by land: extremes (super hot in summer, freezing in winter)
-areas near water: moderate temperatures year round

IONIZATION OF WATER AND pH
1. if H+ = -OH then water is neutral
2. if H+ > -OH then water is acidic
3. if H+ < -OH then water is basic

These three points make up the base of the pH scale

pH Scale- how acidic or basic a solution is measured on a 1 through 14 scale

1 being super acidic, 14 being super basic, 7 is neutral

Buffers- chemicals that allow control of pH measure

Lastly, here are a couple of lameo macaques

2007-11-06T18:52:00.001-08:00

On Monday, we learned about the chemistry of life. Although this is an AP Biology class, we study chemistry because it is the foundation of Biology.

As many of us have learned across the hall in the Chemistry rooms, everything is made of matter. Matter is made of atoms that are made up of electrons, protons and neutrons.
In this biology course, we only need to worry about ten elements on the periodic table: hydrogen, magnesium, potasium, sodium, calcium, carbon, nitrogen, oxygen, phosphorus and sulfate. Hydrogen, carbon, nitrogen, and oxygen are the key elements that our human body is made up of. Phosphorus is in DNA and ATP.

We also went on to learn about the bonding properties and the effect of electrons. Electrons determine the chemical behavior of an atom, depending on the the number of electrons in an atom's outermost shell. The valence shell is nonactive.
Atoms with many electrons in its valence shell have high electronegativity and tend to want to "steal" electrons from other atoms while atoms with fewer electrons have low electronegativity in their valence shell and tend to want to "donate" to other atoms. These atoms with fewer electrons donate bececause they cannot hold that many electrons themselves. These tendencies drive chemical reactions and create bonds. A chief principle that we learned Monday was that when we think of weak bonds, hydrogen bonds should be the very first thing we think of while when strong bonds are mentioned, covalent bonds should be thought of immediately. Covalent bonds are strong because two atoms share a pair of electons and both atoms hold onto the electrons, making them very stable. This forms molecules. The more pairs of electrons shared, the stronger the bond. More is better!

PAGEMASTER will be our next sherpaaaaa!

And That's The Way The Cookie Crumbles!

2007-11-01T13:46:00.001-07:00

IMPORTANT NOTE: The following post does not reflect the views of it's author. It is simply reflective of what we learned in class, and the information provided is not supported by it's provider.

Welcome folks, to another exciting round of Biology Jeapordy with your host....

The wonderfully talented (and good looking!) Alex Trebek!

So basically, today in class we covered Critical Periods, Various Animal Behaviors (operant and classical conditioning), Social Behaviors, and BioMagnification. So our categories will be.....

1) Critical Periods 2) Various Animal Behaviors 3) Social Behaviors and.....

4) BioMagnification-----surprise!

CRITICAL PERIODS

So, what are these things anyway?

Critical periods are just what they sound like: critical periods of time in which an organism is expected to learn something, which can usually only be learned within the critical period.

For example, language in humans is learned during a critical period. Children who don't learn to speak within this critical period aren't usually able to grasp the complexity of our language.

Critical periods are interesting, aren't they? Why can an organism learn to do something at one period in their life, but not after that? Like they say, you can't teach an old trick a new dog. Or something like that.

Various Animal Behaviors

To easily understand how and why animals act the way they do, it's best to split the topic up into two sections:

1) Innate Behaviors (or instinctive behaviors)
2) Learned Behaviors

While I would love to take the time to explain both to you, I'm not going to! We learned about learned behaviors today, and innate behavior yesterday. So if you need help on innate, consult Sean's post.

--Learned Behaviors--

Learned behaviors are behaviors that organisms learn throughout their lives. For example, most species of birds learn their song from their parents and the birds around them.

When studying learned behaviors, it is imperative that you know the following terms.

Associative Learning-learning to associate one feature of the environment with another.

Operant Conditioning-trial and error learning; associating behavior with reward or punishment.

Classical Conditioning-Associating a "neutral stimulus" with a "significant stimulus"

Operant Conditioning is easy enough to remember. Just think about Skinner's box, and the mouse's repeated action of pressing the lever to get food.

After pushing the lever for the first time (and every time after that), the mouse gets a piece of food. The mouse then learns to associate the act of pushing the lever with a reward.

The ingenious man who came up with this experiment was B.F. Skinner.

Classical Conditioning should be no problem for us AP students either! Just think about Ivan Pavlov and his experiments with the dog and the bell.

Before each time Pavlov fed the dog, he rang a bell. Then, by just ringing a bell, he could get the dog to salivate, expecting food. This experiment demonstrates classical conditioning because the dog is connecting a reflex behavior (salivating at the sight of food) to associated stimulus (the ringing bell).

Let's give it up for Ivan Pavlov!

(Ivan Pavlov)^^^

Next we should talk about Social Behaviors.

Social Behaviors

To understand the social behaviors of animals, we should know:

Habituation-loss of response to stimulus (think of "The Boy Who Cried Wolf", in which animals learn not to repond to repeated occurrences of stimulus).

--Language--
Many animals use some form of language to communicate. Communication between individuals is necessary for mating, protection, and finding food.

Examples of language in animals are the songs birds use to find mates, and the honey bee's waggle dance.

--Agonistic Behaviors--
Agonistic behaviors are behaviors that animals perform to outcompete others. These behaviors are generally not threatening, but are instead ritualistic behaviors performed to impress mates, and to establish a social rank.

--Altruistic Behaviors--
Altruistic behaviors are behaviors which are performed which reduces individual fitness but increases fitness of recipient.

A perfect example of this is found in the Belding ground squirrel. These crazy squirrels make noise when predators are near, endangering themselves but incresing the chance of survival of their families and offspring.

The next important thing to understand is the concept of pheromones.

--Pheromones--
Pheromones are chemical substances that stimulate a response from other individuals. The most common pheromone types are alarm pheromones and sex pheromones.

These are vital to the animals success, protection, and reproduction.

So the next time that sweaty person stting next to you smells of bad B.O., just think....

...is this disgusting, or seductive?

--Cooperation--

Some animals cooperate with eachother to help get food, protection, or resources. This can best be associated with a mutualistic symbiotic relationship, because both individuals benefit.

Examples of cooperation include:

1) African dogs who hunt together in packs to help bring dow prey more quickly.

2) White pelican and dolphins who "herd" fish to make it easier for the whole group to eat.

--Colonial Mammals--

Colonial mammals are those who have a queen, breeding and non-breeding workers, and a whole social heirarchy.

Some examples of these include:

1) Bees

2) Ants

3) Termites

4) Mole Rats

And since mole rats are all your favorite animals to look at.....

And now....... (finally)

BioMagnification

BioMagnification is a pretty easy concept to grasp. Basically, it's just the idea that if a substance is introduced to an organism on the bottom of the food chain, then it will increase in concentration as it travels up the food chain. This is due to the fact that a secondary consumers eat several primary consumers, and get more of a concentration of the substance. In turn, tertiary consumers eat more than one of the secondary consumers, and obtain an even greater concentration of the substance.

So the overall lesson of this post? There is a reason why animals act the way they do, and it's important to know the reason.

HOWS MY POSTING??

CALL 1-800-GUD-POST

All those in favor of having Mrs. Foglia dress up as a witch everyday post "I."

All those in favor of having Mrs. Foglia dress up as a pirate everyday post "Aye."

Let me end this post with a quote: "Mo money, mo money, MO MONEY!"

Well anways this is todays lesson.

2007-10-29T18:47:00.001-07:00

Ecological Succession

What is Ecological Succession you ask? Well i guess i will answer your question for kicks. Ecological Succession is the changes or sequences a community goes through naturally. This is why we like to mow our lawns (not sure if i said that right) because if we did not, a forest would grow in your backyard, literally (although you must be really lazy and not mow it for about 50+ years). There are two types of Ecological succession:

Primary succession

This is when an ecosystem is forming life (plants) from all inorganic material (no soil).

In this succession life must begin from Pioneer species such as, bacteria (a.k.a. beasties), lichens, and mosses, which can break down the lifeless material such as sedimentary rock and use its compounds to release nutrients into the ground making soil and setting the stage for other organisms such as grass.

Secondary succession

This succession takes place where their had previously been life, usually having been wiped out by some type of disturbance such as Forest fires, and tsunamis.
This is usually taken place on soil with an abundance in nutrients, making plants grow more quickly.

Order of succession

First ones to come into play are the pioneer species including lichens, and mosses which can start on both primary and secondary succession. These start releasing nutrients, making soil and initially starting a whole living ecosystem.
Next are grasses which can tolerate high sunlight, and also set the stage for other plants changing soil pH, and fertility.
After are shrubs and small trees which are more tolerant to shade and starts to out-compete grass for sunlight.
The final stage in succession is climax forest, this creates a very stable community, containing tall trees. Once a disturbance such as a forest fire occurs (which eventually must happen because of the lack of available nutrients)

Only if this family had been given Sherpa for todays lesson maybe they would have realized their situation and prevented a tragedy such as this.

Earth's biomes

For starters, a biome is defined as an area of similar environmental factors and ecosystems. This includes abiotic factors such as climate, water, light, temperature, and nutrients, and biotic factors such as animals, plants, and biodiversity. There are many different biomes on earth such as (important biomes):

Marine

Aquatic Biome
Intertidal zone, where the tide allows for immense biodiversity.
Shallow water where Coral reefs strive, and aquatic flora (plant life).
Benthic zone, bottom of ocean where organisms are able to strive without the use of sunlight but by the use of sulfur .

Tropical forest

High Rainfall
Supports large amounts of Fauna (animal life) and Flora, supporting up to 2/3 of all these organisms.
Large leave trees, broad, woody flanges at trunk
Tall trees allow for layers of different ecosystems

Temperate Deciduous Forest

North hemisphere, mid-latitude
Broad leaf trees, (Oaks, Beeches, Maples, and Birches).
Warm and rainy climates

Taiga

Coniferous forests (woody plants, gymnosperms( needle trees))
large temperature range between summer and winter
low precipitation
Fauna consists of mostly herbivores, not enough energy to support numerous carnivores

Arctic Tundra

Impossible for growth of trees because of low temperatures, and short seasons
permafrost soil ( permanently frozen soil)
supports low ground Flora such as liverworts,moss, and lichens.
low biodiversity
few species with large populations

http://youtube.com/watch?v=tWS7sWKT9Uo

Hola, Well anways this is todays lesson.

2007-10-29T18:47:00.000-07:00

Ecological Succession

What is Ecological Succession you ask? Well i guess i will answer your question for kicks.

Symbiosis

2007-10-25T19:55:00.000-07:00

Symbiosis: two or more kinds of organisms interact in often elaborate relationships

Types of Symbiosis
1. Competition (-/-): organisms compete for limited resources, when they compete there is less to go around for everyone
Example: Brown-Headed Cowbird & other birds' nest

2. Parasitism(-/+): one species benefits but the other is harmed
*parasites sometimes kill the host thus becoming predation
Example: tapeworm & human

3. Mutualism (+/+): both participating species benefit
Example: clown fish & anemone

4. Commensialism (+/0): one species benefits while the other neither benefits nor is harmed;
*it is often difficult to be certain whether or not the second partner receives a benefit or not, there is no clear cut boundary between commensalism & mutualism
Example: epiphyte

Animal Defense against Predators
Predation drives evolution

(provides strong selective pressure on both predator side and prey side)
Predator adaptations lead to prey adaptations

Predator adaptations: to locate & subdue
Ex: talons, speed, coloration, horns

Prey adaptations: to elude & defend
Ex: spines, thorns, coloration, & toxins

Cryptic coloration (blend in with background)
Aposematic coloration (bright warning to predators)

Mimicry
Batesian: harmless species mimics a harmful model
*convergent evolution: two species on different paths evolve to have the same
structures

Mullerian: two or more protected species look like each other
*predators evolve an innate avoidance (group defense) like people to bees

Community Ecology

2007-10-24T17:46:00.000-07:00

A community consists of all the organisms that live together in one place. To be a community these organisms have to interact with one another. Whether its by competition or predation. Community ecology by it self is the study of interactions among all populations in one area.

A common mistake made is the confusion between a niche and a habitat. So what exactly is the difference? A habitat is the place in which an organism lives. On the other hand a niche is the specific job that an organism does within a habitat.

In the diagram above it shows competition within a niche. If the species on the bottom was removed then the smaller (darker species in the picture) species on top will take over and occupy the entire tidal zone. Although at lower depth the species on the bottom will out -compete the species on the top excluding it from the niche.

Competitive exclusion is when no two similar species can occupy the same niche during the same time (as shown in the diagram above).

For example: This is why lions and tigers do not occupy the same habitat as one another. Because they both have the same niche.

A micro habitat is a small habitat within a much lager one... for example, in the rain forest each lizard has the same niche. But because they live in different levels of the rain forest there is no competitive exclusion occurring.

There are four different types of symbiotic interactions within a habitat. These interactions affect what goes on in the ecological community. These are the four symbiotic interactions:

Competition-(-/-)

Predation/ Parasitism

Mutualism

Commensalism

2007-10-22T13:49:00.000-07:00

Heyya Period 1&2,
this is what today’s lesson was all about!

We talked about the growth of populations on Earth and the effect they have on our planet. We learned that the Logistic rate of growth can grow exponentially but it is it impossible for it to increase exponentially forever. The logistic rate of growth illustrates the # of organisms in a given environment over time. The variable (K) is used to represent the Carrying Capacity (maximum population the environment can support with no degradation of habitat) and the variable (N), to show the number of individuals in a population. Without natural factors the population would keep increasing exponentially thus exceeding the carrying capacity and devastating the environment and ecosystem. Factors reducing rate of growth as an environment approaches the carrying capacity are but not limited to, competition for resources, mates, nesting sites, disease etc.

The Carrying Capacity (K) can also be altered through changes in an environment. Population Cycles and good years of vegetation or prey can yield increase in population of other organisms. Also this could be reversed. For example in years of drought and lack of resources populations can drop effecting predator prey interaction.

We then proceeded to talk about Human Population growth.

Population growth of humans can be attributed to advances in science and medicine as well as technology and industry. In the year 2005 there were over 6 Billion people on earth and alone china and India held 1/3 of the world’s population. If we continue on like this(82million per year) it is my belief we will reach our carrying capacity.

Developing countries have a higher fertility rate than that of developed countries (90% of births are in these developing countries) to lessen this increase we can educate people to make the decision to not have as many kids.

If people were educated I believe we could curb this increase and

even lessen population growth in the years to come.

An Ecological Footprint (EF) is how much an individual effects the environment.

It compares human consumption of natural resources with planet Earth's ecological capacity to regenerate them.

Finally in response to todays lesson I feel that its our duty as individuals

on this green earth to help stop the injustices done to the enviorment..

As Captain Planet and the Planeteers say "The Power Is Yours!"

Ecology Part II

2007-10-22T13:24:00.000-07:00

Ecology Part II

Population Growth

Change in population= births-deaths
Today we were indroduced to the exponential model of population growth. The exponential model is based upon having ideal conditions within population growth.

The exponential model has five variables:

N= number of individuals

r= rate of growth

ri= intrisic rate (maximum rate of growth)

t= time

d= rate of change

the formual is: dN/dt=riN

If a pair reproduces two offspring no population growth will be seen because those two offspring will only be replacing that one pair. If a pair produces four offspring not only will there be a replacement for the pair but an added two more into the population, thus increases the population size.

Exponential Growth Rate

- characteristics of a population without any factors limiting it.

- Some factors that may limit a population are an organisim being introduced to a new enviorment or it having to rebound from a catastrophe.

- Exponential Growth Rate can be seen through the growth in population of both the African Elephant and the Whooping crane which barely survived exctintion, but are slowly fighting there way back.

Regulation of Population Size

There are factors in which limit the regualtion of a population size. These factors can be categorized in to two selections; density dependent and density independent or biotic and abiotic factors.The density dependent factors are food suppy, competition, predetors and disease.The density independent factors are sunlight, temperature, and rainfall.

Introduced New Species

-Non native species are when a population is put into and new area and the population exponentially grows
- When these non native species are put into this new area, though it may seem benifical, at times placing a species to a new surronding backfires. These species now no longer have there native predetors such as diseases or other organisims, they now lack competitors, and there is a lack of natural controls leaving them to do as they please since there is no longer anything that can hinder their growth or activites. There also becomes a reduction in diversity again due to the fact that there usually are no other organisims to surpress their activites.

A good example of this are the zebra mussels which after being introduced to a new enviorment very rapidly spread and cling on to any found objects.

The purple loosestrife is a very good example of how introductiong a new species in to an enviornment can also reduced diversity. Overtime the loosestrife spreads itself and seems to over take its surronding areas.

Ecology

2007-10-18T17:03:00.000-07:00

Today, we learned how to read and interpret demographics. Demography is used to measure factors that affect the growth and decline of a certain population. These factors are used to measure risk and are used to impliment laws such as restrictions on land use, ect.

The diagram to the left shows the average life expectancy of each cohort, or group that travels through life together, of male and female belding ground squirrels. Females generally live longer lives than males and produce mor offspring than can survive, a theory introduced by Darwin.

The graph to the right shows the maximum life spans of the human, the hydra, the oyster. Humans are generally type 1 ( high death rate in post-reproductive years). Hydra are type two (constant mortality rate throughout the life span). Oysters are type 3 (very high early mortality but the few survivors then live long and stay reproductive). Because of this situation, oysters make a ton of babies but do not provide any care for them while humans make few babies and yet invest a lot in raising them. We call the behavior of the oysters "r-selected' and the humans "k-selected".

FUNGI: Domain Eukaryote

2007-10-14T19:08:00.000-07:00

There are classification criteria’s for every domain group
whether its bacteria, archaea, and eukarya. The characteristics for the eukarya is mostly made of multicellular organisms, except for unicellular yeasts. There are two types or reproduction preformed by this group. They are asexual, and sexual. An important part of the structure of fungi is the cell wall. The fungi contain the read-like cells also known as filamentous. There are multi nuclei in the cells.
The fungi actually live in the food that they eat. They paralyze their prey, feeds on living organisms, and breaks down dead remains. The fungal group is made of four diverse sub-groups. They are chytridiomycota, zygomycota, basidiomycota, and ascomycota.

Fungals are decomposers, and work to recycle nutrients. Throughout this group are symbiotic relationships such as fungi and algae. As well as fungi and plants. These relationships enable plants to obtain water into the roots, and put species in ecosystems. Mycorrhizae is the name of an important role in plant growth made by the symbiotic relationship of fungi and plants. A plant is able to grow at larger extents, and more rapidly. Yeast is an example of a fungal that uses budding to create asexual reproduction. Haploid spores go together with + and - for sexual reproduction. Wind is a contributor of sexual reproduction by spreading of spores.

This diagram is an example of the life cycle creating bread mold.

This diagram shows basidiomycete life cycle.

http://www.youtube.com/watch?v=oDt271wfLe4&mode=related&search

Plants Part II

2007-10-11T18:22:00.000-07:00

In Greek Angiosperm means "enclosed seed".
Angiosperms are the most complex, efficient and colorful out of all of the plants
Unlike the other plants Angiosperms protect their embryo with a hard outer coating.
Angiosperms are flowers, and fruit.
Flowers
4 parts of a flower
Petals- Surround the reproductive organs. Often brightly colored to attract insects.
Sepals- Surround and protect the flower bud. They serve as an extra protection in between the petal divisions.
Stamens- The male organ of a flower which contains pollen.Pollen contains male gametes, which fertilize the carpels in other flowers. Adaptations such as prevention of self pollination have increased diversity and have allowed for more change.
Carpel-Female organ of a flower which contains the stigma,style and the ovary.
Flower Variations
There are over 250,000 species of flowering plants.
There are so many different variations. Variations attract different pollinators.
Yellows, reds and blues attract bees.
White with a nice scent attract bats.
http://www.youtube.com/watch?v=zYFcXlex3ds
This clip shows bees going into a flower and feeding on its sweet nectar.
Not only are the bees benefiting off this flower, but the flower is benefiting off them too. While these bees are feasting they are getting pollen(male gametes) all over their coat now when they go to the next flower the gametes will go into the carpel and fertilize the egg of another flower.Another interpertation maybe that these bees have already feasted and now are just getting a snack plus fertilizing this flowers egg. This is a symbiotic relationship(mutually benneficial).Because of the insects/animals plants do not have to make as much pollen because they provide a more direct and efficient way for fertilization.
If its got seeds its a fruit
Fruits spread and protect seeds.
The next generation is in that seed.
There are two classes of Angeosperms. This depends on the number of cotyledons an Angiosperm has.
Cotyledon- the first leaf or leaves of a seedling.
Seedling- A young plant developing out of a plant embryo of a seed.
These are found in all fruits but some may contain one cotyledon(seed leaf)
and others contain two.
Monocot- one cotyledon seed leaf
Dicot- two cotyledon seed leaves
Monocots Vs. Dicots
Monocots Dicots
Embryos with a single cotyledon Embryos with two cotyledons
Floral parts in threes Floral parts in fours or fives
Parallel leaf vains Net like leaf veins
pollen grains has one pore or furrow Pollen grains has three pores or furrows
Vascular bundles throughout stem's Stem vascular bundles arranged in a ring
ground tissue Examples are (woody plants,trees
Examples are (grasses, palms and and beans)
lillies)

Just something ammusing http://www.youtube.com/watch?v=ByHh5_t_rAg

Plant Kingdom

2007-10-10T11:42:00.000-07:00

Plants are members of the Domain Eukarya.

For a large part of the earth's past the land was barren and no life existed. It wasn't until about 500 million years ago that land plants evolved.

Some of the earliest plants evolved from ancient protists like the "Chara" shown below.

Plants fall under four smaller categories Bryophytes, Pteridophytes, Gymnosperm, and Angiosperm.

Bryophytes- Are land plants that don't have a vascualr system like moss. This means that they have to live very close to water and they can't grow very tall, as water and nutrients could not be transported to the upper parts of the plant.

Pteridophytes- Are Vascular plants that lack seeds. Although these plants can grow taller they still must remain fairly close to water as their sperm are transported through water(swimming sperm) just like Bryophytes.

Gymnosperm- Are the conifers, these plants have pollen and "naked" seeds meaning they do not have a fruit covering the seed. Pollen allows conifers to colonize almost any enviornment because their seeds can now travel through the air and do not rely on water for transport.

Angiosperm- Are the flowering trees that are most prevelant in our area. Angiosperms have flowers and fruit to cover their seeds. Flowers are used to attract birds and insects to help spread their pollen.

Life Cycles- Unlike humans and all other mammals plants spend much more of their life cycle as haploid organisms. This means at any given moment a plant could have only one pair of chromosomes while in humans there are two.

This video explains the life cycle of a fern very nicely. I apologize for not being able to embed the video.

http://video.google.com/videoplay?docid=2342399186796367569
Due to the lack of time i cannot cover all life cycles of each group of plants but the concept between them is very similar.

Classification

2007-10-02T16:51:00.000-07:00

In the old classification system, there was the:

Monera
protists
plants
fungi
animals

There is now a Three Domain system which includes:

Bacteria
Archaebacteria
Eukaryote - which includes:

protists
plants
fungi
animals

-In this new classification, the Monera has split into the bacteria and archaebacteria which are more different than humans and plants.

- We learned that bacteria are everywhere! which means they are on our and animals bodies, in our bodies, in the soil, in the ocean depths, in extreme environments, and on the dead as well as the living.
This is a volcanic vent in the ocean; an example of one of the extreme conditions bacteria live in. They form colonies on the vents and get energy from the sulfur gas being released.

- The main bacterial shapes are rods, spheres, and spirals.

-Prokaryotes are unicellular and lack internal organization. They possess no endoplasmic reticulum, vesicles, mitochondria, or chloroplasts. They do however have ribosomes.
- Prokaryote cells are 1/10 the size of eukaryotes and have a "naked" DNA. Their DNA is not wrapped around proteins like ours.

Variations in Cell Interior
- In Cyanobacterium bacterium or photosynthetic bacterium, there is an enfolding of the external membrane. The enzymes involved in photosynthesis are located in the membranes, so with the more enfolding, the more photosynthesis and energy and sugar will be produced.
- In Aerobic bacterium the membrane contains enzymes involved in respiration. Therefore, the more enfolding the more energy will be produced.

Prokaryote Cell Wall Structure
- Gram Positive Bacteria's cell wall is made of peptidoglycan which is polysaccharides (sugars) and amino acid chains together which form a rigid cell wall. These bacteria will take up a stain and turn purple.
- Gram Negative Bacteria's cell wall is made of lipopolysaccharides which is lipids (fats) and polysaccharides (sugars) together. Due to the fats, the gram negative bacteria will not soak up the stain and will turn red.
- Why is this important?
-The difference in gram negative and positive bacteria is crucial for doctors when treating an illness. The gram negative bacteria are more resistant to antibiotics because of the fats. This is important for doctors to determine in order to know how much of or what kind of antibiotic to give a patient.

Prokaryotic Metabolism

Photoautotrophs- photosynthetic bacteria. Using power of the sun.
Chemoautotrophs- oxidize inorganic compounds such as nitrogen, sulfur, and hydrogen. Do not need the sun.
Heterotrophs- live on plant and animal matter. They live on creatures that have made the food already. They are decomposers and pathogens.

- Mutations
- Bacteria reproduce every 20 minutes by binary fission.
- They can reproduce asexually
- There is a 1 in 200 error rate in copying DNA. The high resistance to antibiotics is due to this error rate and the rapid pace at which bacteria reproduce.
- Bacteria can mix genes. They have lots of plasmids which are supplemental circles of DNA (genomic). The bacteria can send out these circles of DNA and others can pick them up thus further spreading the mutation.
-This is both advantageous and detrimental to us. Because of their quick reproduction it is easy for doctors to get the genes they want in the cells and to get them to reproduce these genes. However, it is detrimental because it spreads resistance.

- Pathogens are disease causing microbes. In Plants they cause wilting, fruit rot and blights.
In Animals they can cause tooth decay, ulcers, anthrax, botulism, STDS, plague, leprosy, Lyme disease, and pneumonia among many others.

- Bacteria are good too!
- Bacteria act as decomposers and recycle the nutrients from the dead to the living.
- Bacteria are the only organisms that can fix nitrogen from atmosphere which is essential for synthesis of proteins and nucleic acids.
- They help in digestion by digesting cellulose for herbivores.
- They produce vitamins K which clots blood and B12. This is a mutual symbiotic relationship. As the bacteria gets to eat, we are getting vitamin K.
- They can produce foods like yogurt and medicines like insulin.

Ah Yes, The Origin Of Life

2007-09-26T12:13:00.000-07:00

Life as we know it is great, isn't it? I mean, we pay $1.75 for lunch everyday, we get hot chocolates in between periods 1 and 2, and we get do have.....well.....we get to engage in some controversial acts of impurity during AP Bio. But how did humans, and all animals for that matter come to be as they are today? We know evolution by Natural Selection has influenced the inhabitants of the world immensely, but where did these "common ancestors" that we talk about every day come from? How did cells come to be as they are today? And why does Sean fall asleep everyday in first period? All of these questions will be answered in this post.

What is Life?
Before we discuss how life came to be, we should first understand what life is.

Living things will always:
1) be comprised of cells
2) respond to stimuli (though not always to the same stimuli, nor in the same way)
3) maintain homeostasis
4) use energy to grow
5) change and mature
6) reproduce

So every living thing we know of obeys all of the "rules of life" as listed above, right?

WRONG!!!!

As we learned today, viruses are made of protein, and use animals to reproduce. These six rules of life apply to most animals. And for those planning to use number 6 as an excuse to "hop on the good foot and do the bad thing", living things only have to have the ability to reproduce. Those who dont "get busy" are still deemed alive!

So, how did life come to be?

How Life Came To Be
There is no proven theory about how life began, but there are several hypotheses.

One hypothesis is one which is supported mainly by the Bible and believers in God.

Special Creation suggests that life began simply when God made it.

This hypothesis is NOT TESTABLE, and we can never be sure if this hypothesis is correct. This is obviously not the only hypothesis.

Extraterrestrial Origin suggests that organic materials came from comets and meteorites striking the Earth.

The important thing to remember about this theory is that it does not suggest that we descended from this guy....

It merely suggests that organic molecules arrived on Earth in comets and meteors that struck the Earth.

Spontaneous Abiotic Origin, which is the theory that suggests that the Big Bang occurred, states that life spontaneously evolved from inorganic molecules.

To see a video (only the first 40 seconds or so are really relevant) about the big bang, go here:
http://www.youtube.com/watch?v=igLaWRgpn5w&mode=related&search
(sorry I couldn't embed it!)

Anyway....

The Condition Of Earth In It's Early Stages
When the Earth was first..."boomed" into existence, the atmosphere was completely unfit for humans and organisms like us.

Oceans were boiling...

.....Free oxygen was missing from the atmosphere....

....And lightning, UV radiation, and Volcanoes were the sources of energy.

So which Hypothesis Of The Origins Of Life is most likely???

Well, scientists Miller and Urey (with an "assist" by scientists Oparin and Haldane) modeled the conditions of early life as described above, and concluded that Spontaneous Abiotic Origin was possible. This is also the theory that is most widely accepted in the science community.

Origin Of Genetics
RNA stands for Ribonucleic Acid. RNA is like DNA, only without the sugars.
RNA is believed to be the first genetic material, as it encodes information, is able to replicate itself, supports evolution and inheritance, and has enzyme functions.
Some scientists opposed this idea by suggesting that the first genetic materials were proteins (enzymes). They argue that RNA, or anything for that matter, could not reproduce without enzymes.

BUT THE PROTEIN THEORY, as it has come to be known as, IS NOT BELIEVED TO BE CORRECT! So don't let that confuse you.

Key Events In The Origin Of Life
First off, the Earth....

...into existence 3.5-4 BILLION YEARS AGO!!!

Prokaryotes were great in number on Earth between 3.5 to 2 billion years ago.

The image on the left is what we should focus on here. It is an image of a 3.5 billion year old fossil of bacteria.

Free Oxygen was finally found on Earth 2.7 billion years ago. Photosynthetic bacteria probably produced this oxygen. This oxygen made aerobic respiration possible, which in turn made us and other animals possible.

The first Eukaryotes, who evolved from Prokaryotes, were then present on Earth. Essentially, Eukaryotes were organisms that had cells which contained a nucleus and other cell structures.

The first appearance of an organelle was that of Endoplasmic Reticulum.

Endoplasmic Reticulum is said to have formed when the plasma membrane of early cells folded into itself, and created the passageways which are now found in cells.

Similarly, cells did not originally have a source of energy. Cells were said to have engulfed a photosynthetic bacterium, which would, if not eaten, provide the cell with energy. In return, the cell provided protection and food for the bacterium. Eventually, the bacteria became mitochondria in cells. This is believed because the mitochondria resembles bacteria. The relationship between the cell and the bacterium is called endosymbiosis.

Endosymbiosis is the process of having an internal, mutual relationship with another organism.

Another important event in the developing world was the Cambrian explosion, which was a period of 10-20 million years in which most of the major phyla of animals appeared in the fossil record. This happened 543 million years ago, and heavily supports the theory of punctuated equilibrum, but that's a different story!!!

Other events include the Permian mass extinction, and the Cretaceous mass extinction, which was when all of the dinosaurs were wiped out.

Evolution of early mammals FINALLY began 125 million years ago, and became dominant and most abundant on the Earth.

The last thing we discussed in class today was how scientists classify life. Basically, there are currently 3 domain systems, into which all organisms are organized and sorted. In the domain Eukarya, there are 4 divisions: Fungi, Plantae, Animalia, and Protista.

This was a long class!!! But worth it! Living things are found all around us, and it is important to know where they came from, how they evolved, and how we organize and study them.

I'll leave you off with a quote:

"If God put me in your plans or not, I'm trippin', this drink got me sayin' alot, But I know that God put you in front of me." Kanye West (Stronger)

So what hypothesis of life does Kanye believe???

Thankyou for reading. I hope it was informative enough!

The Origin of Species

2007-09-25T13:47:00.000-07:00

Species: a species is a population whose members are able to interbreed wih each other and create viable(survivable) and fertile offspring. The members of a species must also be reproductively compatible. Although some organisms may be a part of the same species, they may not look alike. And some members of the same species may be prevented from breeding due to certain factors.

The images above show an eastern and a western meadowlark, which although they are in the same species, do not mate due to differences in songs and behavior.

Species originate by many different evolutionary processes. Populations can become geographically and reproductively isolated. If populations are isolated, they evolve independently from one another. In order for a new species to originate, a population has to be separated from other populations. This isolation can occur in different countries (allopatric isolation) or in the same country (sympatric isolation).

There are many pre-reproduction barriers that can prevent mating or fertilization in a species. These six barriers are geographic isolation, ecological isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation.

-Geographic Isolation: When there is a physical barrier that causes the species to occur in seperate areas. This is an allopatric or "different country" isolation.

-Ecological Isolation: When species occur in the same area but live in different environments, so they rarely come into contact and get the chance to reproduce. For example, lions and tigers are biologically able to reproduce and create viable, fertile offspring, but since lions live in the grasslands and tigers live in rainforests, they rarely come into contact with each other and do not get the chance to mate.

-Temporal (time based) Isolation: When species breed at different times of the day, different seasons, or different years and do not mate. This is a sympatric or "same country" isolation. For example, in certain species of cicadas, some cicadas reproduce every 13 years while others reproduce every 17 years, so the two groups never cross paths and reproduce.

-Behavioral Isolation: When unique behavioral patterns and rituals isolate species. These unique behaviors help identify members of a species and attract mates of the same species. For example, Ms.Foglia's favorite birds, the blue-footed boobies, have a courtship display that is unique to their species, and they will not mate until that courtship display is completed.

-Mechanical Isolation: When structural differences prevent successful mating. For example, in many closely related species of plants, there are certain differences, such as differences in color, that help attract different kinds of pollinators.

-Gametic Isolation: When the sperm of one species may not be able to fertilize the eggs of another species. This can be due to chemical incompatibility or a biochemical barrier that prevents the sperm from entering the egg. For example, some sea urchins may release their sperm and eggs at the same time, but the gametes of different species may be unable to fuse.

Post-Reproduction Barriers: These barriers can prevent hybrid offspring from developing into a fertile, survivable adult.

-Reduced Hybrid Viability: Genes of different parent species could interact and impair the hybrid offspring's development.

-Reduced Hybrid Fertility: No matter how strong a hybrid offspring is, they may still be unable to reproduce due to differences in structure or number of chromosomes of parents that may impair the offspring's ability to produce normal gametes. For example, mules, which are a hybrid of a horse and a donkey, are unable to reproduce because they have 63 chromosomes and cannot make normal gametes.

-Hybrid Breakdown: Although hybrids may be fertile in the first generation, when they mate their offspring can become weak or sterile.

Rate of Speciation

There is a debate about whether speciation happens gradually or rapidly over time. In the theory of gradualism by Charles Darwin and Charles Lyell, they believe that new traits emerge gradually over long spans of time, and that big changes are due to the accumulation of many small changes over a long period of time. They believe that the rate of change is constant. In the theory of punctuated equilibrium by Stephen Jay Gould and Niles Eldredge, they believe that the rate of speciation is not constant and that changes take place over hundreds of thousands of years rather than millions. They also believe that there are long periods of time with little or no change.

That basically sums up the origin of species that we learned about today in class. If you have any questions, just ask and I'll try to help.

Evidence of Evolution by Natural Selection (cont.)

2007-09-24T16:53:00.000-07:00

Evidence of Evolution by Natural Selection

Homologous Structures:

Homologous structures are bones with similar structures and similar developments but different functions. They have different niches, or jobs due to variations in the population that accumulated over time and served as adaptions.

In the picture above, there is a homologous structure in all six individuals most likely because they all have a common ancestor and over time have evolved from their ancestor to carry out different functions.

Comparative Embryology:

Comparative embryology is the similar development of embryos in closely related species.

At different stages of development, there are similar structures that exist in vertebrate embryos. In the individuals above, there is a gill pouch present in each vertebrate. However, that does not mean that humans have gills because we don't. It is really thyroid glands, not gills that is in humans. Comparative embryology shows species with similar ancestors.

Molecular Record:

Molecular record is comparing DNA and protein structures. All organisms have the genetic codes DNA and RNA. The sequences are more similar in species that are closely related than those that are distantly related.

The further apart species are, the more protein structure changes. DNA changes as protein structure changes because of agents such as mutation.

"Family Trees":

Closely related species branched off from the same ancestor and share same line of descent. This was also one of Darwin's theories.

Testable Hypotheses

Peppered Moths:

In the year 1848, 5% of the population was dark colored moths while 95% was light colored.

In the year 1895, 98% was dark colored while 2% was light colored.

In the year 1995, 19% was dark colored while 81% was light colored.

What was the reason for the changes in the number of dark and light colored moths?

In the early 1800s, England was not so industrialized yet and pollution was still low. The trees had light colored bark so the light colored moths had a better advantage and a better survival rate than dark colored ones.
In the late 1800s, England started to become more industrialized and factories increases. These factories caused trees to become soot coated, the bark was darker. The dark colored moths were then camouflaged and survived more than light colored ones.
Then in the mid 1900s, the air started to become cleaner due to clean air laws. Trees began to have lgiht colored barks and once again light colored moths increased in the population.

Industrial melanism- melanin is the brown color in all organisms.

Genome Sequencing:

Are humans closely related to monkeys???

Genome sequencing shows us the evolution of humans and how we share a common ancestor with apes.

Orangutans, gorillas, and chimpanzees have 48 chromosomes while humans have only 46. So where's the missing chromosomes?

In order to prove that humans are related to apes then humans must have a fused chromosome, 23 pairs. A chromosome must be found that is in the middle and another one that is inactived.

Well that is exactly what was found in humans. Chromosome 2 shows the fusion that took place. In chromosome 2, there are telomeres at the ends and two that have fused together in the middle. One inactive centromere also exists in chromosome 2.

Here is proof that apes and humans really are related.

Need any more proof???

Hardy Weinberg Lab

2007-09-21T09:39:00.000-07:00

On Friday September 21st we went over the Population Genetics Lab. In this lab we had four cases. Each case represented one of the agents of evolution. It was supposed to represent Hardy Weinber's theory of equilibrium but our population wasn't big enough to correctly test whether or not his theory of evolution is accurate or not. In case #4 it represented the evolution agent of genetic drift, because we were only allowed to mate with our population and not migrate anywhere to reproduce. This agent went against Hardy's theory because he saw that evolution happened through migrating with different individuals and not just individuals in your population.

-- This website explains Hardy Weinberg's theory and what agents of evolution make it false, which is what we discussed while going through this lab: Hardy Weinberg

For the first 3 cases we had 23 individuals which meant 46 alleles, and then for the last case we had 8 individuals and 16 alleles. After collecting your individual data we combined the whole classes data together and calculated the frequency of the genotypes.

For the ones that were absent here are the frequencies:

Formula used to calculate this data:

Case #1:
Generation# :
p2 (AA)- parental=.25 F5=.04

2pq(Aa)- parental=.5 F5=.43

q2(aa)- parental=.25 F5=.52

Frequency of alleles:
p(A)-.5 q(a)-.5

p(A)-.26 q(a)-.74

Case #2:
Generation# :
p2 (AA)- parental=.25 F5=.78
2pq(Aa)- parental=.5 F5=.22
q2(aa)- parental=.25 F5=.0

Frequency of alleles:
p(A)-.5 q(a)-.5
p(A)-..89 q(a)-.11

Case #3:
Generation# :
p2 (AA)- parental=.25 F5=.30
2pq(Aa)- parental=.5 F5=.70
q2(aa)- parental=.25 F5=.0

Frequency of alleles:
p(A)-parental=.5 q(a)-parental= .5
p(A)-F5= .65 q(a)-F5= .30 (didn't do F10)

Case #4:
Generation# :
p2 (AA)-
parental=.25 F5

(Group 1)=.375
(Group 2)=.125
(Group 3)=.0

2pq(Aa)-
parental=.5
F5
(Group 1)=.125
(Group 2)=.1875

(Group 3)= .1875

q2(aa)-
parental=.25
F5
(Group 1).25
(Group 2)=.0625

(Group 3)=.1875

Frequency of alleles:
p(A)-.5
q(a)-.5
p(A)(Group 1)= .875

(Group 2).4375
(Group 3)=.5625

q(a)
(Group 1)=.125

(Group 2)=.5625
(Group 3)=.25

In this lab the change in allele frequency wasn't representing that the white homozygous recessive cats died but representing evolution making white homozygous recessive cats less common than black cats. There were white cats made but they didn't get to live to the age of mating. Alleles determine the type of genes a creature has, whether the parents pass on dominanttraits so that the offspring survives in their environment or a parent passes on a recessive trait which gives that offspring a less percentage for survival.

- A cute cartoon on the evolution of cats.

Measuring Evolution of Populations

2007-09-20T18:52:00.001-07:00

Measuring Evolution of Populations.

Hardy-Weinberg formulas:

The formula for alleles is p+q=1. We must assume that there are two alleles. p is the frequency of the dominant allele, and q is the frequency of the recessive allele. The frequencies must add to one, therefore p+q must equal one. The formula for individuals is p²+2pq+q²=1. p² is the homozygous dominant frequency. q² is the homozygous recessive frequency, and 2pq is the heterozygotes frequency. The frequencies must add to 1, so p²+2pq+q² will equal one.

Sickle cell anemia:

Sickle cell anemia is very painful as well as it can be fatal. It strikes 1 in 400 African Americans, which is a lot! Sickle cell anemia is a mutation in the gene coding for hemoglobin, which is what carries oxygen in red blood cells. The recessive allele is H^s H^s, and the normal allele is H^b. When a person has sickle cell, what is happening is the red blood cells are breaking down, and instead of being round cells they become crescent like shapes and cannot flow smoothly. Therefore, blood vessels get clogged and organ damage occurs. This can be very painful.

Sickle cell has the highest frequency in heterozygotes(H^b H^s). 1 in 5 central Africans, which is a huge number, are heterozygotes. 1 in 100 are homozygous. They usually die before their reproductive age. Since the H^s allele has such a high level in the African population, it suggests that there was an advantage of being heterozygous.

Malaria:
Malaria is also common in Africa. It is caused by a mosquito bite which contains a single celled eukaryote parasite, that spends part of its life in red blood cells. It basically goes from the mosquito into the humans blood stream, it then goes to the liver to mature and reproduce, and then goes to the red blood cells where it eventually bursts them open. The person will those thousands of blood cells, get a high fever, and can sometimes die.

Advantage for Heterozygotes:
In Africa, homozygous dominant (H^b H^b) die of malaria, homozygous recessive (H^s H^s) die of sickle cell anemia, and heterozygote carriers (H^b H^s) are mostly free of both. This gives a huge advantage to heterozygotes, and could be good explanation for an excessive amount of heterozygotes in Africa. They are the ones surviving.

This is what we went over today. It wasn't too hard, but if you need help just ask.

The Evolution of Populations

2007-09-19T20:46:00.000-07:00

September 19th- AP Bio Lesson
The Evolution of Populations

First, it’s important to emphasize that individuals do NOT evolve, populations evolve.
When an individual is born with a variation beneficial for survival and aiding in their reproduction, that varying trait will get passed down from generation to generation. With that, it’s necessary to remember that variation is the raw material of evolution.

So what causes this change? Sure, by this point, we know all about selection, but what else? There must be other things, right? Right, there are 5 agents of evolutionary change.

1. MUTATION
a. Mutations can come about by both DNA mishaps in mitosis (cell division) and meiosis (gamete division) or by environmental influences such as UV light rays.
b. The likelihood of a particular mutation is not affected by natural selection. Mutations do not occur more frequently in situations in which they would help the organism survive and reproduce.
c. Here’s a pretty informative youtube video on mutations:

2. GENE FLOW
a. Gene flow is the movement of alleles from one population to another.

3. NONRANDOM MATING
a. individuals with certain genotypes sometimes mate with another more commonly than would be expected on a random basis
b. assortative mating: type of nonrandom mating in which phenotypically similar that causes the frequencies of particular genotypes to differ greatly from Hardy Weinberg principle (I’ll discuss that later)
disassortative mating: phenotypically different individuals mate producing a lot more heterozygotes

4. GENETIC DRIFT
a. frequencies of particular alleles may change drastically by chance alone as if the frequency was drifting.
b. two types: founder effect and bottleneck effect
Founder effect- the effect by which rare alleles and combinations of alleles may be enhanced in new populations
-Not rare in nature, new populations could be started with a single seed (albino deer)
Bottleneck effect- when a population size is dramatically reduced- may it be because of flooding, disease, the actions of human beings, etc.- and several alterations and losses of genetic variability in that population.

4. SELECTION
We know this one, super easy but to review:
a. Natural selection to occur: variation must exist, variation among individuals results in differences in the number of surviving offspring to the next generation, variation must be genetically inherited.
b. Selection passed on helps to: avoid predators, match climatic conditions, for pesticide resistance, for sexual advances, increase survival and in turn reproduction
So we understand all that stellar selection info but what makes a change due to natural selection favorable? Biologists measure success on quantity of surviving offspring or fitness. Good fitness is passed on from parent to offspring and those possessing the trait will have greater reproductive success.

Now for the tough part, math in biology, boooo.

THE HARDY WEINBERG EQUATION
p +q = 1
(p+q)² = p²+2pq+q²
P= homozygous dominant q= homozygous recessive 2pq= heterozygous
Used to calculate genetic frequencies in decimal form
Hardy and Weinberg pointed out tat the population will remain constant from generation to generation if:
1. the population size is very large
2. random mating is occurring
3. no mutation takes place
4. no genes are input from other sources (no immigration)
5. no selection occurs
If no other forces are working against it, the process of sexual reproduction (meiosis and fertilization) alone will not change the Hardy- Weinberg proportions.
If the proportions do not change, the genotypes are said to be in Hardy- Weinberg equilibrium.

although at first hard to grasp, the math thing is pretty simple if you look at examples, like the one on page 436 of the textbook and the one in our “Measuring Evolution of Populations” powerpoint

Evidence of Evolution

2007-09-18T15:39:00.000-07:00

Hi, here are some key points we should have picked up from today's lecture

-Evolution is among us and there is alot of proof
-Fossil records of transition species
-Similar embryologic developement
-Similar protien and DNA sequences
-Fossil records show us the ancestral species to today's organisms and how adaptations have slowly changed the population
-They can also show common ansestry in extremely different organisms today, The wrist bone in several mammals are the same to show relation

-Analogous structures
-similar parts of organisms in terms of use but have different internal structure and origin
-NO evolutionary relationship, the species just had similar solutions for similar problems

-Parallel Evolution
-a species fills similar ecological roles in similar environments, so similar adaptations were selected
-not closely related
ex: marsupials in australia and placental mammals elsewhere
-Common ancester millions of years ago, but once separated evolved differently

Hope this helps clear things up!

2007-09-17T18:32:00.001-07:00

Chuck Norris is the peak of evolution

"There is no theory of Evolution Just a list of creatures Chuck Norris has allowed to live."

Sexual Selection

2007-09-17T16:57:00.002-07:00

Hello there. This is Ryan and I'm going to teach you about sexual selection. Sexual Selection is a part of natural selection. Sexual selection is one way that nature weeds out those unfit to live. Those who are best fit to live will survive, and go on to reproduce. First how a mate is picked. The female usually picks the mate. Why you might ask? Well the female has to sit home and nurture the young, while in many cases the male is planting his seed in other places (if you know What I mean) They protect the young , and if its an egg they sit on it, or if it is a placental organism they also have to give it nutrients. The males of the animal kingdom have many features that can make them attractive to women. As shown in the image above from "The Descent of Man and Selection in Relation to Sex" by Charles Darwin the ornate Tufted Coquette on the right is the male, and he is trying to attract the female. Charles Darwin...What a guy.

A classic sample of the "pretty" males in animal society is the Peacock. The Peahen will choose the Peacock with the most beautiful plumage. This is an example of Koinophilia. Koinophilia is when sexually active organisms prefer mates with a preponderance of common or average features. Another reason for the fancy train on the peacock is to distract predators. Predators see the fancy feathers and think they are a weak female, and when they see the drab brown peahen they mistake them for males.

The lion's mane is another sexual attractant. In the lion kingdom Mane's are the main thing. A female will pick her mate based on a lion's mane. At first when females picked the lion's with the biggest mane's it wasn't if that lion would be a good food survivor, or would it be good in protecting the family. It just so happened that it worked out. The longer, thicker and darker a males mane was correlates with the testosterone levels in that lion. It also mean the lion has good health, more muscles and aggression, better(more fertile) sperm, and a longer life. This made them much better mates.

One species that live in Panama, and other parts of South America is the Jacanas. The female Jacanas is a pimp in the animal world. She has many males impregnate her and she lays eggs all over ponds. She must do this so that the species will live on because the ponds were they lay eggs are swarming with crocodiles. So she has all the fathers sit on the eggs. and eventually many will hatch.

The offspring gets the behavior and morphology, and the traits that get you mate passed on from the parents. So if your parents are ugly troll-like creatures you most likely belong under a bridge.

Here are some pictures of other animals with features that make them sexy

These fiddler crabs are chosen by the size of there claws. During mating season the male crab will either pick his claw up in the air and wave or slam it on the ground to attract females.

HOLY ANOLE!!!!!!!!!!!!!!!!! This bad boy makes his throat look like a strawberry, and the females would like to get a piece of that if you know what I mean.

"Violence is my last option."
--Chuck Norris

The School of Hard knocks

(1940- )

Natural selection

2007-09-12T08:19:00.000-07:00

Hi guys, yesterday in class we learned about natural selection. Well what is natural selection? It is the process by which favorable traits are inherited and passed down from generation to generation. In other words, it helps them to survive better, hence the phrase "survival of the fittest." Well natural selection is helpful in predation, physiology, and sexual selction.

Predation selection

The preying mantis is a perfect example of predation selection. The preying mantis has blended in with the leaves. This enables it to remain hidden so it can catch prey easier. Isn't that amazing!!

The fastness of a cheetah is also due to natural selection. By running fast, it is able to catch its prey. The extremely long legs also help it to run fast enough.

Physiological selection

When the Antarctic ocean had frozen over, some of the fish had developed an anti-freeze like chemical in their body. This helped them to survive in the cold waters of the Antarctic Ocean. This anti-freeze like, ice-binding chemical was then passed on to the next generation.

Sexual Selection

This is the ability to attract mate and maintain a successful rearing of offspring. Males in the animal kingdom show spectacular displays to attract female mates. Lets have a look:

Ever wonder what a lion's mane is for? It for attracting females duh!!

The peacock is another example. The peacock is using his beautiful display of feathers to attract mate. Its so beautiful!!

This was yesterday's lesson. Well if you guys have any questions feel free to ask me!!

Evolution

2007-09-11T12:58:00.000-07:00

Hi. Well today during class we finished up the PowerPoint from yesterday and we also did about 2 slides from today’s PowerPoint. Then during second period we finished up our lab and went over the summary questions with Mrs. Foglia.
Here are the highlights from today’s notes: (the Roman numeral is the slide name and the letters are some of the main points of the slide.

Correlations of species to food source:

Correlation between different species and food types

A lot of behavior is genetically controlled what you eat, etc.

Adaptive Radiation: when a species arises in a new area, it has the adaptation to live in a new niche because they have successful inheritance or successful traits

Darwin’s Finches:

The beak differences between the finches allowed them to survive in their specific environment and allowed them to pass on those successful traits to their offspring.

Correlation of species to food source:

Darwin had noticed that among the tortoises, the shape of the shell corresponds to different habitats

This shows that depending on the environment and the availability of food, or in this case where the food is, adaptations can occur throughout a species to help them survive in that environment, just like the finches.

Many islands locally show variation in tortoise morphology: which is the shape of the body and through this evidence Darwin questioned that this is the reason why there was splitting of one species into several

Artificial Selection:

In this selection, nature does not select who gets to reproduce, but humans do like in agriculture.

We saw in class some examples of artificial selection in plants how they all were from the same species or ancestor but were different

Selective Breeding

On the slide we see a breed of pigeons which went through artificial selection. All of these pigeons came from the same ancestor.

This is further evidence to the fact that parents pass on traits to their offspring

A reluctant revolutionary

Darwin returns to England in 1836 with his idea of evolution and natural selection

He wrote papers describing his journey and he had finished his draft of species formation in 1844

Wanted his wife to publish his essay when he dies

He was scared to tell the world of his ideas because his ideas went against he science of the time and he did not want to ruin his career

Wallace’s Letter to Darwin

Wallace wrote a letter to Darwin asking him to review the letter he had wrote about the same idea Darwin wrote about but was reluctant to publish

The time was ripe for the idea

They both agreed to publish the their essays simultaneously that way they both can get the credit for their founding

Essence of Darwin’s ideas

5 characteristics

Variation: any group of organisms in a population must have differences

More offspring are born than can possibly survive

As a result of overpopulation struggle for existence or competition

Characteristics that benefit the species and allow them to survive and reproduce, will be passed on to the offspring and soon that characteristic will be common in the population, changing the average characteristics of the population and this is called adaptations

Over a period of time, new variation comes in population and these processes lead to the emergence of new species

Natural Selection

All of the five characteristics refer to natural selection

Variation, overpopulation, competition, and differential survival based on traits

Successful traits leads to adaptations adaptations must be genetic to pass on to offspring

LaMarckian vs. Darwinian view:

LaMarck believed that since giraffes were stretching their necks to reach the food, that acquired long neck got passed on to their offspring

Problem: traits are determined by genes and that how they are passed on. He did not involve genes, he said that it just got passed on without genes

Darwin believed that longer necked giraffes were surviving better and therefore getting to reproduce and pass on their traits to their offspring through genes

Effects of Selection:

Directional selection natural selection pushed the population to one extreme side of variations variations lead to one of the tail or the edge

Stabilizing selection natural selection pushes the population to the middle of the population.

Disruptive Selection over time each extreme gets selected, over time no one is really in the middle and this is the beginning of speciation

Natural selection

Selection happens on any trait that effects survival and reproduction

Predation selection, physiological selection(how bodies work), sexual selection(the traits that allow you to get a mate)

Well that’s what we learned today and please do forgive me if I left something out or if my outline did not help you. If you have any questions or comments please post it on the blog or just reach me at school, in the classroom and you can ask me there.

Navneet

This site will give you a better definition and example of artificial selection

This site will give you more details about the Galapagos tortoises

History of Alfred Wallace

The whole LaMarck and Darwin view of the Giraffes neck

This video shows a Galapagos tortoise walking:

Evolution by Natural Selection

2007-09-10T16:46:00.000-07:00

Today we learned about Evolution by natural selection.

I have called this principle, by which term Natural each slight variation, if useful, is preserved, by the Selection.

-- Charles Darwin, The Origin of Species

We learned:

-- Species have been evolving since the beginning of time and that the earth was not the same now as it was billions of years ago.

-- The fossil record is a clear indication of evolution and natural selection because the fossils show that there are differences between the dead species and the living species, and the advantages that the living species had over the dead species.

-- LaMarck, a contemporary of Darwin, believed that species acquire traits during their life time. NOT TRUE!! It takes a species many generations to evolve and acquired adaptations! That is why if you get a nose job in your life time, your children will still inherit your original nose.

-- Lastly, we talked about the endemic species on the Galapagos Islands. The finches were of great importance because through study of these birds, Darwin was able to conclude and support his theory of evolution and natural selection. This is because the finches all had evolved to eat different foods and survive differently.

Vegetarian Finches

Here is a video from YouTube about a man who actually camped out on the Galapagos Islands for two years and documented his stay there:

That’s about it. This was the first blog so I wasn’t to sure how to go about it but I hope I was helpful. If anyone has any questions, comments, corrections, or anything please feel free to comment and I will get back to you when I can.

Addition Websites that can be helpful:

Toward the middle of the page there is a section that illustrates the four main parts of Darwin’s Theory:
Evolution and Natural Selection

This is actually a website where you can plan a trip to the Galapagos Island. The website has a lot of interesting pictures as well as prices and travel packages: Galapagos Tours

Look Mrs. Foglia: A Red-footed Booby!

PS. If any one has any trouble posting photos, let me know and I'll show you how.

How to Blog Safely

2007-09-09T17:53:00.001-07:00

Blogging is a very public activity. Anything that is posted on the Internet stays there. FOREVER! Deleting a post simply removes it from the blog it was posted to. Copies of the post may exist scattered all over the Internet. That is why we need to be careful and follow some simple, clear, safety rules.

FIRST RULE:
To protect your privacy, you need to set up your account using ONLY your first name. This means that many of you need to go in and change your profile. If you have the same first name as another classmate, then let's add only your last initial to your first name, like KimF.

SECOND RULE:
We do not use pictures of ourselves in our profiles. If you really want a graphic image associated with your posting use an avatar -- a picture of something that represents you but IS NOT of you.

Other teachers who have blogged with their classes have come up with a list of guidelines for student bloggers.

One of them, Bud Hunt, has these suggestions, among others:

Students using blogs are expected to treat blogspaces as classroom spaces. Speech that is inappropriate for class is not appropriate for our blog. While we encourage you to engage in debate and conversation with other bloggers, we also expect that you will conduct yourself in a manner reflective of a representative of this school.

Never EVER EVER give out or record personal information on our blog. Our blog exists as a public space on the Internet. Don’t share anything that you don’t want the world to know. For your safety, be careful what you say, too. Don’t give out your phone number or home address. This is particularly important to remember if you have a personal online journal or blog elsewhere.

Again, your blog is a public space. And if you put it on the Internet, odds are really good that it will stay on the Internet. Always. That means ten years from now when you are looking for a job, it might be possible for an employer to discover some really hateful and immature things you said when you were younger and more prone to foolish things. Be sure that anything you write you are proud of. It can come back to haunt you if you don’t.

Never link to something you haven’t read. While it isn’t your job to police the Internet, when you link to something, you should make sure it is something that you really want to be associated with. If a link contains material that might be creepy or make some people uncomfortable, you should probably try a different source.

Look over the guidelines and add any ones you'd like to suggest in the comments section below this post. I think Bud's suggestions are excellent -- clear and easy to follow. We'll be using these from now on as the basis for how we will create our blogs.

You've got to pay attention to the list of "What Not To Do"!

Regards,

KBF

Cycle 2 Sherpa Guide List

2007-09-04T14:11:00.000-07:00

This is the list of possible Sherpa Guides for Cycle 1 of blogging. Pick our next Sherpa from this list. If a classmate has served as a Sherpa Guide then their name will be crossed off. Choose one of the names that hasn't been crossed off.

updated Nov. 20, 2007

Alexander
Ashley
~~Courtney~~
~~Daniel~~
Deeba
Jaclyn
Jennifer
Jessica
~~Lauren~~
Lisa
Melissa
MichaelM
~~MichaelV~~
~~Muskan~~
~~Navneet~~
Nick
~~Paige~~
RyanG
RyanR
~~Sarah~~
Sean
StephenM
StephenS
~~Thomas~~

Welcome to Our Virtual Classroom

2007-09-03T14:08:00.000-07:00

We started blogging this summer, but now we are going to take it to the next level. This will be your blog for AP Biology (Period 1 & 2) for the whole year. Let me make that clear -- this isn't MY blog; this is OUR blog. This blog is what you'll make of it. I'll prod a bit to get you started, but you can then take it as far as you want, to make it a helpful learning environment for all of you.

Since I strongly believe that you don't really learn something until you have to teach it to someone else, we will use this blog for students to teach students. Each day a student in class will be assigned to be the class sherpa -- our guide who will show us the clear path up the mountain of knowledge. I will appoint the first sherpa, but after that... today's sherpa will pass their baton on to the next sherpa of their choosing. This will serve as 50% of your participation mark for the quarter.

What will the sherpa do here?

Summarize the day's lesson.
Highlight the important points of the lesson -- especially highlighting concepts exemplifying the 8 themes of biology (more about these later).
Highlight any unanswered questions left after the class.
Help clarify any points of confusion left after class.
Point us to resources that help learn today's lesson -- like animations, videos, diagrams, photos, other teacher's Web sites that illustrate concepts we've been learning.

AP Biology 2007 (Period 1&2)

Science Debate 2008

Immune system

HORMONES

Better to breathe like a camel than look like one...

Immune System

Circulation in Animals

Jan. 10

Digestion continued...

Digestion

Nutrition

What is the point? TO MAKE ATP

Activators and Inhibitors

Metabolism and Enzymes

The Nervous System

Regulating The Internal Environment Part 2

Monday Dec. 3

Regulating The Internal enviorment

Movement Across the cell membrane

REGULATING THE INTERNAL ENVIORNMENT

Diffusion 101

Theme 8: SCIENCE, TECHNOLOGY & SOCIETY

Theme 7: INTERDEPENDENCE IN NATURE

Theme 6: REGULATION

Theme 5: RELATIONSHIP OF STRUCTURE & FUNCTION

Theme 4: CONTINUITY & CHANGE

Theme 3: ENERGY TRANSFER

Theme 2: EVOLUTION

Theme 1: SCIENCE AS A PROCESS

Our Grand Tour of the Cell

Nucleic Acids

Protein's Cont'd

Proteins

Carbohydrates !

Chemistry of Carbon

And That's The Way The Cookie Crumbles!

Well anways this is todays lesson.

Hola, Well anways this is todays lesson.

Symbiosis

Community Ecology

Ecology Part II

*Ecology*

FUNGI: Domain Eukaryote

Plants Part II

Plant Kingdom

Classification

Ah Yes, The Origin Of Life

The Origin of Species

Evidence of Evolution by Natural Selection (cont.)

Hardy Weinberg Lab

Measuring Evolution of Populations

The Evolution of Populations

Evidence of Evolution

Sexual Selection

Natural selection

Evolution

Evolution by Natural Selection

How to Blog Safely

Cycle 2 Sherpa Guide List

Welcome to Our Virtual Classroom

Ecology