Monday, October 29, 2007

Well anways this is todays lesson.

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):

  • 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
  • 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

Hola, Well anways this is todays lesson.

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

Thursday, October 25, 2007


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)

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

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

Wednesday, October 24, 2007

Community Ecology

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:

  1. Competition-(-/-)

  2. Predation/ Parasitism

  3. Mutualism

  4. Commensalism

Monday, October 22, 2007

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

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.

Thursday, October 18, 2007


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".

Sunday, October 14, 2007

FUNGI: Domain Eukaryote

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.

Thursday, October 11, 2007

Plants Part II

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.
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.
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)

Just something ammusing

Wednesday, October 10, 2007

Plant Kingdom

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.
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.

Tuesday, October 2, 2007


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:
  1. protists
  2. plants
  3. fungi
  4. 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.