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 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 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 Teacher

4. Evidence from embryos Embryos show similar development, including structures that are not present in the adult “At some point in their development, all vertebrate embryos have a post-anal tail, as well as structures called pharyngeal (throat) pouches. These homologous throat pouches ultimately develop into structures with very different functions, such as gills in fishes and parts of the ears and throat in humans and other mammals.” –Campbell, 9e

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.