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Notes – Evidence for Evolution Please add this title to your notes… Evolution • Definition: a change in the genetic information of a population over many generations Evidence for Evolution 1. Fossil evidence • • Fossils show gradual changes in the structures of organisms throughout Earth’s history Fossils show that many species have become extinct Evidence for Evolution 2. Evidence from artificial selection • Artificial selection shows changes in plants and animals due to humans breeding them 3. Evidence from Homologous structures • = Bones or other body parts that are similar between different species • Example: the limb bones of mammals Vestigial structures Vestigial structures Vestigial structures • = Homologous structures that are no longer useful but served important functions in the organism’s ancestors • Example: – Pelvic bones in whales – Appendix in humans Are these wings homologous? Analogous structures • = Similar structures in different organisms that have a different evolutionary history • Example: – Wings in bats and birds Analogous structures • = Similar structures in different organisms that have a different evolutionary history • Example: – Wings in bats and birds Challenge: Embryo Puzzle Embryo Puzzle: Answers 4. Evidence from embryos • Embryos show similar development, including structures that are not present in the adult 5. Molecular evidence for evolution • All living organisms use DNA to store genetic information. • DNA from one organism can be transferred to and used by another organism. • All living organisms use the same 20 amino acids to build their proteins.
