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Ecology
Vocabulary:
-
Ecology - The study of how organisms fit into their
environment.
- Community
- The organisms which live in a particular
environment.
- Habitat
- Physical location of a community
- Ecosystem
- Self-sustaining collection of organisms
& their physical environment.
- Diversity
- a measurement of the number of organisms
inhabiting an ecosystem
Energy in ecosystems:
- Life in any ecosystem is driven by the flow of energy.
- All energy entering the earth's Biome is from the sun.
- Living things are divided into 3 major categories based on how they obtain their energy
- Producers
- Obtain energy from their surroundings
(eg.light)
- Consumers
- Obtain energy from consuming other
organisms
- Decomposers
- Obtain energy from consuming wastes.
- Energy in an ecosystem always flows from producers to consumers
- Organisms are assigned "trophic
levels" according to how many "steps"
they are away from the source of their energy.
- Autotrophs
(like plants) occupy the first level
since they obtain their energy directly from the source
- Herbivores occupy the second level, since they obtain their energy from eating the
autotrophs.
- Carnivores
occupy all higher levels, since they
obtain energy from eating herbivores (and other carnivores)
- Omnivores
can occupy more than one trophic level
since they can eat all of the above.
Note: All organisms above the the first trophic level are known as
heterotrophs
since they cannot make their own food, but must obtain it by consuming other organisms.
- Energy flow across trophic levels is inefficient
- Energy is lost between each level.
- Only about 1/10 makes it from 1 level to the next.
Food Webs
Energy moves through an ecosystem in a complex pattern. The interactions of energy flow
is best viewed as a food web.
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Mr. Stanley
Last updated May 20, 2002