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Evolution and Biodiversity: Origins, Niches, and Adaptation

Evolution and Biodiversity: Origins, Niches, and Adaptation. G. Tyler Miller, Jr.’s Environmental Science 10 th Edition Chapter 5. Key Concepts. Origins of life. Evolution and Evolutionary processes. Ecological niches. Species formation. Species extinction.

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Evolution and Biodiversity: Origins, Niches, and Adaptation

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  1. Evolution and Biodiversity: Origins, Niches, and Adaptation G. Tyler Miller, Jr.’s Environmental Science 10th Edition Chapter 5

  2. Key Concepts • Origins of life • Evolution and Evolutionary processes • Ecological niches • Species formation • Species extinction

  3. Earth: Just-right Resilient Planet • Temperature • Liquid water • Rotation • Size and gravity • Ozone layer • Life Fig. 5-1, p. 92 DO NOT POST TO INTERNET

  4. Origins and Early Evolution of Life • Chemical evolution • Biological evolution Fig. 5-2 p. 93

  5. Modern humans (Homo sapiens) appear about 2 seconds before midnight Recorded human history begins 1/4 second before midnight Age of mammals Age of reptiles midnight Insects and amphibians invade the land Origin of life (3.6–3.8 billion years ago) Plants invade the land First fossil record of animals Plants begin invading land noon Evolution and expansion of life Biological Evolution Over Geologic Time Fig. 5-3, p. 94

  6. Biological Evolution • Evolution • Theory of Evolution • Microevolution • Macroevolution

  7. Microevolution • Gene pool • Alleles • Mutations • Natural selection

  8. Natural Selection • Differential reproduction • Adaptive trait (adaptation) • Artificial selection • Coevolution

  9. Peppered Moths and Adaptation Fig. 5-4, p. 96

  10. Directional Natural Selection Natural selection Average New average Previous average Snail coloration best adapted to conditions Number of individuals Number of individuals Average shifts Coloration of snails Coloration of snails Proportion of light-colored snails in population increases Figure 5-5a, p. 97

  11. Stabilizing Natural Selection Natural selection Dark snails eliminated Light snails eliminated Snails with extreme coloration are eliminated Number of individuals Number of individuals Coloration of snails Coloration of snails Average remains the same, but the number of individuals with intermediate coloration increases Fig. 5-5b, p. 97

  12. Diversifying Natural Selection Intermediate-colored snails are selected against Snails with light and dark colors dominate Natural selection Light coloration is favored Dark coloration is favored Number of individuals Number of individuals Coloration of snails Coloration of snails Number of individuals with light and dark coloration increases, and the number with intermediate coloration decreases Fig. 5-5c, p. 97

  13. Ecological Niches and Adaptation • Ecological niche • Fundamental niche • Habitat • Realized niche Fig. 5-6 p. 98

  14. Broad and Narrow Niches and the Limits of Adaptation • Generalist species • Specialist species • Limits of Adaptation Refer to Spotlight p. 99

  15. Specialized Feeding Niches for Birds Herring gull is a tireless scavenger Brown pelican dives for fish, which it locates from the air Black skimmer seizes small fish at water surface Ruddy turnstone searches under shells and pebbles for small invertebrates Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation Flamingo feeds on minute organisms in mud Knot (a sandpiper) picks up worms and small crustaceans left by receding tide Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Piping plover feeds on insects and tiny crustaceans on sandy beaches Louisiana heron wades into water to seize small fish Fig. 5-7, p. 100-101

  16. Misconceptions about Evolution • “Survival of the fittest” • “Progress to perfection”

  17. Speciation, Extinction, and Biodiversity • Speciation • Geographic isolation • Reproductive isolation Fig. 5-8, p.100

  18. Factors Affecting Speciation and Extinction • Plate tectonics • Climate changes over time • Natural catastrophes • Human Impacts

  19. Extinction and Recovery • Background extinction • Mass extinction • Mass depletion • Adaptive radiation • Human Impacts

  20. “Continental Drift” (Plate Tectonics): The Breakup of Pangaea LAURASIA LAURASIA PANGAEA PANGAEA 120° 80° 40° 80° 120° 120° 80° 80° 120° GONDWANALAND GONDWANALAND 135 million years ago 225 million years ago NORTH AMERICA NORTH AMERICA EURASIA AFRICA 120° 80° 120° 120° 0° 40° 120° INDIA SOUTH AMERICA MADA- GASCAR MADA- GASCAR AUSTRALIA AUSTRALIA ANTARCTICA ANTARCTICA 65 million years ago Present Fig. 5-9, p. 101

  21. Impact of Speciation and Extinction on Biodiversity “Biodiversity = Speciation – Extinction” Human impacts on extinction and biodiversity Recovery of biodiversity Genetic engineering

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