03 Population Ecology

03 Population Ecology - Populations, Communities, and...

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Populations, Communities, and Species Interaction I. Critical Factors and Tolerance Limits A. Critical Factor-single factor in shortest supply relative to demand B. Tolerance Limits-min and max levels beyond which a species cannot survive/reproduce C. Many species exhibit tolerance limits that are narrower for young than adults II. Adaptation: Groups of traits are concentrated, allowing a population to survive & reproduce A. Individuals with advantageous traits survive (natural selection) B. Occurrence of traits increase each generation C. New traits may arise through mutation D. Leads to slow change in a species: Evolution III. Natural Selection: better competitors survive and reproduce more successfully A. Random mutations create genetic diversity B. Limited resources or environmental cond. may exert selective pressure 1. Physiological stress due to environmental levels of a critical factor. 2. Moisture, Light, pH, nutrient availability 3. Predation 4. Parasitism, Disease 5. Competition IV. Speciation : In time, mutations collectively allow a species to become better suited to new conditions A. Divergent - Separation of one species into new species B. Convergent - Unrelated organisms evolve to look and act alike V. Taxonomic Naming System-binomial system
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This note was uploaded on 05/25/2011 for the course BIO 105 taught by Professor Staff during the Spring '08 term at Grand Valley State.

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03 Population Ecology - Populations, Communities, and...

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