Evidence of Evolution

1. Evidence of Evolution How Scientists Determined that Living Things Change Over Time Video #3 – “How Do We Know Evolution Happens?”

2. Fossil Record • Fossil = remains of any living things or their prints • Fossils include: • Bones • Casts or molds • Impressions Top left – impression of a worm; center – cast of a mollusk; right – humerus bone of a turtle “Becoming a Fossil” – 2:34

3. Comparative Anatomy- body parts • Comparing the structures of organisms • Similarities indicate evolutionary relationships.

4. Comparative Anatomy, cont’d • Homologous structures – have similar insides • these have a similar structures and may or may not have a similar function • indicate common ancestry:

5. Comparative Anatomy, cont’d Analagous structures – have similar outsides these have a different structure but similar function indicate common environmental pressures:

6. Comparative Anatomy, cont’d • Vestigial structures – seem to have little or no importance in modern organisms • Indicates that the structures were useful (a long time ago) • The pelvis (and femur) of a whale is a vestigial structure; • it suggests that ancestors of whales had four legs • Humans also have vestigial structures • Tonsils & Appendix Whale Evolution – 5:09

7. Comparative Embryology • Closely related organisms appear to go through similar stages as embryos “Common Past, Different Paths” – 1:36

8. Comparative Biochemistry / Molecular Biology • There is a common genetic code DNA • Analyzing and comparing DNA sequences and proteins can show a relationship among species. “The Common Genetic Code” – 4:20

9. The genetic similarities between humans and primates indicates that we share a common ancestor – NOT that humans came from apes! • Humans are more similar (genetically) to chimpanzees than to gorillas or orangutans. This suggests that humans and chimpanzees split / branched off from our common ancestor more recently than gorillas and orangutans. “Human Chromosome 2” – 3:27