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15 Cards in this Set
- Front
- Back
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What is an ecosystem?
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An ecosystem consists of all species in a community, their interactions with one another, and their interaction with the abiotic factors in the environment.
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Why are ecosystems more complex than systems?
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Ecosystems are more complex than communities due to the input and output of energy and the input, transfer, and cycling of chemicals among trophic levels.
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Which physical laws must ecosystems obey?
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Ecosystems must obey the following physical laws:
Ecosystems require external energy and must transform it into a biologically useful form of energy. Energy is lost when it is transferred between trophic levels. Only some of the energy in consumed food is converted into new cells and tissues. Ecosystems require chemical inputs. |
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Which trophic levels contribute to bringing inorganic nutrients into an ecosystem?
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primary producers, some consumers
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Which trophic level introduces biologically-useful energy into their ecosystems?
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primary producers
(photosynthesis, chemosynthesis) |
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What source is required of ecosystems to act as co-factors for enzymatic reactions?
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chemicals
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What introduces biologically-available nitrogen into ecosystems?
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Nitrogen-fixing species introduce biologically-availbale nitrogen into ecosystems.
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Which 3 types of functional groups are necessary to maintain a sustainable ecosystem?
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Producers, decomposers, and Nitrogen-fixing species
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What role do decomposers play in an ecosystem?
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Decomposers release and recycle nutrients from dead organic matter.
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Which trophic level has the greatest number of individuals?
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primary producers
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Which trophic level has the greatest biomass (weight of cells and tissues)?
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primary producers
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Which trophic level has the greatest collective energy?
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primary producers
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What does the Green World Hypothesis state?
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The Green World Hypothesis states that ecosystems are stable because primary producer populations are stable.
Plants have impressive immune systems. Herbivore population size is stable due to-- plant (phyto) toxins calorically-poor plant tissues abiotic factors that limit their carrying capacity predation by higher-level consumers |
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Why are nitrogen-fixing species essential to ecosystems?
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Nitrogen-fixing species provide ecosystems with the raw material to make proteins and nucleic acids.
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How is biomagnification created in ecosystems?
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Trophic relationships cause lipid-soluble chemicals to increase and accumulate at each higher trophic level.
arsenic DDT mercury PCBs toxaphene |
