4.1
SPECIES, COMMUNITIES, AND ECOSYSTEMS
Essential Idea: The continued survival of living organisms, including humans, depends on sustainable communities.
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Nature of Science: Looking for patterns, trends, and discrepancies: plants and algae are mostly autotrophic but some are not.
UNDERSTANDINGS:
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Species are groups of organisms that can potentially interbreed to produce fertile offspring.
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Members of a species may be reproductively isolated in separate populations.
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Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods).
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Consumers are heterotrophs that feed on living organisms by ingestion.
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Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.
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Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion.
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A community is formed by populations of different species living together and interacting with each other.
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A community forms an ecosystem by its interactions with the abiotic environment.
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Autotrophs obtain inorganic nutrients from the abiotic environment.
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The supply of inorganic nutrients is maintained by nutrient cycling.
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Ecosystems have the potential to be sustainable over long periods of time.
APPLICATIONS & SKILLS:
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Skill: Classifying species as autotrophs, consumers, detritivores, or saprotrophs from a knowledge of their model of nutrition.
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Skill: Setting up sealed mesocosms to try to establish sustainability.
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Skill: Testing for association between two species using the chi-squared test with data obtained by quadrat sampling.
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Skill: Recognizing and interpreting statistical significance.
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