Sep 22 2010
Ecology
Today’s class was dedicated to ecology. We started class by defining the levels of life. Here is what we found (most inclusive is on the top and least inclusive on the bottom):
- 1. Biosphere: the sphere of life
2. Biome (*place): many different types of ecosystems; ex: desert, rainforest
3. Ecosystem: Place and community (and level of life) [Focus of ecology!]
4. Community (*not a place): a group of groups; all populations in an area
5. Population: all individuals of one species in one area
6. Organism (Species-one type of organism): can reproduce
7. Organ System: Related organs working together; ex: endocrine, cardiovascular
8. Organ: group of tissues to perform a specific task
9. Tissue: similar cells that form structural material (work together) (4 Types: connective, muscle, nervous, and epithelial)
10. Cell: building block of life
Next, we learned that an ecosystem is made up of two parts: biotic (living parts) and abiotic (non-living parts).
Biotic is the community aspect of an ecosystem (basically the interactions that take place).
Some abiotic factors include nutrients (both metals and nonmetals{nonmetals include Nitrogen, Sulfur, and Phosphorous}), light, temperature, water, and pH. These are called primary factors. Abiotic factors are non-living factors that affect the environment of an ecosystem.
Other abiotic factors in an ecosystem limiting factors, which govern growth and survival. This is because living things can only tolerate certain parameters. For example, the body can only tolerate a pH level of blood between about 6-8. Also, fish can only live in an environment with a pH of about 5-7. This is called the “Range of Tolerance”: A living thing can only tolerate certain limits.
Another thing we talked about were another was to divide an ecosystem: Habitat and Niche (with organism placed in the middle because they fit into both).
Habitat can be defined as where you live or your “address”. An ecosystem can have many of these. For example, the habitat of phytoplankton is on the top layer of the water because they need sunlight. The habitat of the cattail is on the edge of the water.
Niche can be defined as the “occupation” of something in an ecosystem.
Finally, we talked about the Ecological Pyramid. Here is a link to a picture:
Ecological Pyramid
http://mrskingsbioweb.com/ecology.html
On the bottom are primary producers, or autotrophs (make their own food). This is the only thing that can make biomass, or organic matter that can be used as energy. Autotrophs can do this because they make their food from the sun’s energy and don’t eat. The metaphor Mr. Willard used in class was saying you have a job in the government (not very specific). The rest of the levels are made up of heterotrophs, or organisms that make their own food. The first bottom level of the heterotrophs are the primary consumers (herbivores). Mr. Willard’s metaphor continues, and he relates primary consumers to saying you have a job in banking (slightly more specific). (The top two tiers of the pyramid are carnivores). Next is the secondary consumers, and Mr. Willard relates this to saying you have a job in investment banking. Lastly, there are tertiary consumers, which is like saying that you have a job in doing home loans. Basically Mr. Willard’s metaphor showed that as you go up in the pyramid, the more specific the title of the group of organisms in the trophic level gets. (Also, there are fewer animals in each trophic level as you go up, but that is due to the 2nd law of thermodynamics, not a concept in this lesson)
A good summary, but I don’t think my point with ecological pyramids was that jobs get more specific as you go up. I was saying that in a way, all consumers (levels 2,3,4,5) have “banking jobs,” but each of them has a more specific title (primary, secondary, teritiary) within their field. In general, there will be fewer organisms towards the top, but that is a different concept (due to the 2nd Law of Thermodynamics).