BIOL 112 Lecture 2

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Descent with Modification

Mechanism of evolution is natural selection

different populations change over a long time (many generations) into different species

Before Darwin

1. Aristotle
   • Scala Naturae put forth that organisms were unchanging—no evolution
   • Arranged organisms by increasing complexity (with something visible to naked eye—fungi perhaps—, and humans on top, of course)
2. Genesis: creation, unchanging
3. Carolus Linneaus
   • "father of taxonomy"
   • developed nested classification into groups (Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species) based on shared characteristics (morphology)
   • Darwin viewed shared characteristics in terms of a common ancestry
4. George Cuvier
   • "father of paleotology"
   • Thought fossils indicated extinction and repopulation by other species (catastrophism)
5. Hutton (geologist)
   • Gradualism: change occurs slowly, and "many smaller changes bring about profound change."
   • Analogous to evolution.
6. Lyell (another geologist)
   • Uniformitarianism: Change is slow, and rate is roughly constant.
   • Earth is very old; old enough for evolution to have occurred
7. Lamarck
   • Organisms adapt to environment and acquire characteristics
   • Proposed that those characteristics are passed to offspring (WRONG!)