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Aristotle and early Judeo-Christian culture believed...
that species were fixed and designed by a creator, but there were exceptions
Two main features of Darwin's theory of evolution:
1. diverse forms of life have arisen by descent with modification
2. natural selection
Darwin observed that organisms:
- vary in many characteristics that can be inherited
- produce more offspring than the environment can support
Evolution by Natural Selection:
1. Individuals don't evolve, populations evolve from generation to generation
2. Natural selection can amplify or diminish certain heritable traits
3. Evolution is not goal-directed
Key Points About Natural Selection:
1. more of an editing process than a creative mechanism
2. contingent on time and place
3. significant evolutionary change can occur in a short amount of time
Evidence Supporting Evolution:
fossils, the fossil record, intermediate forms, birds, comparative anatomy, evolutionary trees
features that often have different structures but are structurally similar because of common ancestry
the geographic distribution of species suggest that organisms evolve from common ancestors
comparisons of DNA and amino acid sequences between different organisms reveal evolutionary relationships
occurs when individuals with certain traits are more likely to survive and reproduce compared to individuals with other traits
the transfer of alleles from one population to another, as a result of movement of individuals or their gametes
Natural selection can alter variation in a population in three ways..
1. stabilizing selection
2. directional selection
3. disruptive selection
differential reproductive success owing to variation in the ability to obtain mates
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