1. Notes – Evidence for Evolution
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2. Evolution
Definition: a change in the genetic information of a population over many generations

3. 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

4. Evidence for Evolution
Evidence from artificial selection
Artificial selection shows changes in plants and animals due to humans breeding them

5. 3. Evidence from Homologous structures
= Bones or other body parts that are similar between different species
Example: the limb bones of mammals

6. Vestigial structures

7. Vestigial structures

8. 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

9. Are these wings homologous?

10. Analogous structures
= Similar structures in different organisms that have a different evolutionary history
Example:
Wings in bats and birds

11. Analogous structures
= Similar structures in different organisms that have a different evolutionary history
Example:
Wings in bats and birds

12. Challenge: Embryo Puzzle

13. Embryo Puzzle: Answers
Teacher

14. 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

15. 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.