HED 1: Adaptation by Natural Selection
- Created by: spambeth12
- Created on: 31-03-20 14:24
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- Ch1: Adaptation by Natural Selection
- Explaining Adaptation before Darwin
- No scientific explanation
- Natural Theology, William Paley (1802)
- Darwin's Theory of Adaptation
- 1.Competition 2. Variation 3. Inheritance
- E.g. Finches on the Galápagos
- The Grants'
- Selection preserves status quo when most common type = best adapted
- Evolution doesn't always lead to change in the same direction
- Species are populations of varied individuals that may or may not change over time
- Adaptation results from competition among individuals, not between entire population species
- The Evolution of Complex Adaptations
- Variation is continuous or discontinuous
- Discontinuous variation is NOT important for complex adaptations because they are unlikely to arise in one jump
- Complex adaptations arise from accumulation of small random variations by natural selection
- Requires all intermediate steps to be favoured by natural selection
- Convergence:Unrelated species independently evolve the same complex adaptations, suggests complex adaptations are not just chance
- Rates of Evolutionary Change
- Natural selection can cause change that is more rapid than observed in the fossil record
- Darwin's Difficulties Explaining Variation
- Couldn't explain how variation is maintained
- Explaining Adaptation before Darwin
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