Wednesday, September 26, 2007

Ah Yes, The Origin Of Life

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?


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:
(sorry I couldn't embed it!)


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!

Tuesday, September 25, 2007

The Origin of Species

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.

Monday, September 24, 2007

Evidence of Evolution by Natural Selection (cont.)

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???

Friday, September 21, 2007

Hardy Weinberg Lab

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

(Group 1)=.125

(Group 2)=.1875
(Group 3)= .1875

(Group 1).25

(Group 2)=.0625
(Group 3)=.1875

Frequency of alleles:

p(A)(Group 1)= .875
(Group 2).4375
(Group 3)=.5625

(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.

Thursday, September 20, 2007

Measuring Evolution of Populations

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 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.

Wednesday, September 19, 2007

The Evolution of Populations

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.

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:

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

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

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.

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.

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

Tuesday, September 18, 2007

Evidence of Evolution

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!

Monday, September 17, 2007

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

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- )

Wednesday, September 12, 2007

Natural selection

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!!

Tuesday, September 11, 2007


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.
  1. Correlations of species to food source:

    1. Correlation between different species and food types

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

    3. 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

  2. Darwin’s Finches:

    1. 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.

  3. Correlation of species to food source:

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

    2. 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.

  4. 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

  5. Artificial Selection:

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

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

  6. Selective Breeding

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

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

  7. A reluctant revolutionary

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

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

    3. Wanted his wife to publish his essay when he dies

    4. 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

  8. Wallace’s Letter to Darwin

    1. 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

  9. The time was ripe for the idea

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

  10. Essence of Darwin’s ideas

    1. 5 characteristics

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

      2. More offspring are born than can possibly survive

      3. As a result of overpopulation struggle for existence or competition

      4. 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

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

  11. Natural Selection

    1. All of the five characteristics refer to natural selection

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

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

  12. LaMarckian vs. Darwinian view:

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

      1. 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

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

  13. Effects of Selection:

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

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

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

  14. Natural selection

    1. Selection happens on any trait that effects survival and reproduction

    2. 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.


Monday, September 10, 2007

Evolution by Natural Selection

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.

Sunday, September 9, 2007

How to Blog Safely

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.

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.

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:
  1. 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.

  2. 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.

  3. 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.

  4. 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"!



Tuesday, September 4, 2007

Cycle 2 Sherpa Guide List

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


Monday, September 3, 2007

Welcome to Our Virtual Classroom

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?
  1. Summarize the day's lesson.
  2. Highlight the important points of the lesson -- especially highlighting concepts exemplifying the 8 themes of biology (more about these later).
  3. Highlight any unanswered questions left after the class.
  4. Help clarify any points of confusion left after class.
  5. 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.