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5 modern evolutionary ideas
- 1. central dogma of genetic info
- 2. Evolution most often measured by change in population over many generations
- 3. Evolutionary history resembles a tree
- 4. Evolution NOT teleological
- 5. Adaptation favored & maintained by natural selection
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central dogma of genetic info
- 1. DNA self replication (DNA dep. DNA polymerase)
- 2. transcription of DNA-->RNA (DNA dep. RNA pol.)
- 3. translation of RNA-->protein (ribosomes)
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How is evolution measured in a molecular way
- nucleic acids evolve - thru mutations
- cells evolve - thru aquiring NEW DNA
- individuals evolve - new cells/tissues
- populations evolve - new genotypes
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Evolutionary history tree - Fission
- ends in >2 descendents
- cladogenesis
- Adaptive radiation
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Evolutionary history tree - Fusion
- hybrid speciation
- polyploidy
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Evolutionary history tree - non-branching
- entire population evolved
- anagenesis (one ancestory, one descendent ie: horses)- Darwin's thought to be most common
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Lamarck evolution vs Darwin
- Lamarck coming from a democratic state of the french revolution believed in adaptive change, that every being has the same abilities but will evolve through each generation the same (giraffe)
- Darwin had the aristocratic view of only the fit survive, not everyone has the same chance
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Adaptation w/example
- Adaptation arises by mutations and only is retained if it is favored by the selecting forces
- ie: the white fur of polar bears was adaptation that is retained for survival in the arctic
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