Evidence for Evolution
Evidence from Living Species
- Vestigial structures: whale hind legs, human tail.
- Pseudogenes (no longer code for functional products): vitamin C, hemoglobin.
- Conservation of biochemical pathways: RNA, DNA, humans and flies share 90% of nucleotide sequence for an eye gene (pax6).
- Direct observation: English peppered moths, guppies, finches, insects pests, bacteria.
- Lack of fossils were a problem for Darwin.
- Since then fossils have been found showing transitional forms → species → species extinction.
- Classic examples: horse, whale
Evidence of Homology
- Homology - study of similarities arising from a common ancestor.
- Homologous bones (structures) can be determined in the limbs of humans, birds, horses, bats, seals and turtles.
- Homologous development of embryos.
- Homologous relationships are used to create phylogenies.
Evidence in Biogeography
- Closely related species are tend to be clustered geographically: Kaibab squirrel isolated from Abert's by Grand Canyon.