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Jean Baptiste Lamarck proposed 2 mechanisms of evolution.
- Use and disuse
- Inheritance of acquired characteristics
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Darwin made 4 observations:
- 1) Members of a population vary in their traits
- 2) Traits are inherited from parents to offspring
- 3) All species produce more offspring than the environment can support
- 4) Many of the offspring do not survive
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Natural Selection
different survival and reproduction of individuals within a population
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Homology
Similarity resulting from common ancestry
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Homologous structures
- anatomical resemblances that represent variations on a structural theme present in a common ancestor
- (phalanges, metacarpals)
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Vestigial structures
Remnants of features that served important tunctions in the organism's ancestors
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Analgous
- structures that serve the same function in different species, but are NOT derived from a common ancestral sructure
- (wings, aerodynamic sharks/dolphins)
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