Evolution Biodiversity

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  • 1. Evolution: The change in species over time Charles Darwin: Theory of Natural Selection
  • 2. Theory of Natural Selection
    • Overproduction of offspring : species produce far more offspring than are needed.
    • Competition : space and food are limited so competition occurs for resources. Only fraction can survive
    • Variation among offspring : individuals in a species vary and these are inheritable
  • 3. Theory of Natural Selection
    • Struggle for survival: result of competiton
    • Adaptations due to variations, some individuals are better adapted to survive and reproduce.
    • Natural Selection : environmental factors will select the optimal traits. The “best fit” will survive and reproduce.
    • Speciation : Over many generations, favorable adaptations accumulate and many changes lead to new species.
  • 4. What is the source of Variation? Mutations: Changes in the DNA Sexual Reproduction: Recombination of chromosomes
  • 5. Why is variation important to evolution? Variations within a species increases the chance of survival when conditions change. cichlid fish
  • 6. Fossil Evidence shows Evolutions progresses without set direction. What does it indicate when branches end?
  • 7. How should the finches at the top compare to each other? Why?
  • 8. Observed Natural Selection
    • Insect resistance to insecticides
    • Bacterial resistance to antibiotics
    Explain how this occurs? Variation (mutation) Environmental factor (pesticide) Reproductive success Survival of Fittest Population changes
  • 9. How do we determine which organisms are more closely related?
    • Compare anatomy
    • Compare development
    • Compare biochemistry
    • Compare cells
    Similarity implies relationship!
  • 10. Homologous structures are a clues to determine evolutionary relationships. What could be the reason for similarity in structure?
  • 11. Molecular data is the best way to compare organisms to relatedness. Compare genes, proteins, Which animal is most and least related to the human?