1. Evidence for Evolution
Evidence from dead organisms
Evidence from living organisms

2. Fossils – remains of dead organism
Preserved remains of organisms that lived a long time ago
Fossilized hard parts (most common) ex. Bones, teeth, shells, spores, seeds etc
Traces of fossils (indirect evidence), footprints, leaf prints, tracks, burrows.

3. How does Fossilization occur?
Organism becomes buried in ash or sediments
Rapid burial and a lack of oxygen aid in preservation
The organic remains become infused with metal and mineral ions

4. What Do Fossils Tell Us? Evidence for change through time
Oldest fossil found – heterotrophic bacteria 3.5 BYO
Older fossils in lower layers of rock
Ancestor of the whale walked on land
Younger fossils in higher layers

5. Evidence from Biogeography
Continental Drift
Idea that the continents were once joined and have since “drifted” apart
Pangea: theoretical supercontinent: Explains the worldwide distribution of more ancient life MYA
Laurasia and Gondwanaland: Explains why certain life forms exist in the northern land and some only in the southern lands MYA

6. Evidence from Biogeography
Antarctica has fossils of plants and animals that shows that is was once a warmer land
The continents in the south have unique life forms and fossils form that of the Northern continents
Why are kangaroos only found in Australia
Why are flightless birds only on S. America, Africa and Australia

7. Evidence from Living things Comparative Morphology
Homologous features
Analogous features
Vestigial structure

8. Morphological Divergence or Adaptive Radiation1 2
Morphological Divergence or
Adaptive Radiation 3
PTEROSARUR 4 1 2
CHICKEN 3
Homologous structures: evolved from a common ancestor (so similar in structure) but has changed (different environmental pressures) to serve different functions
STEM REPTILE 2 3
PENGUIN 1 2 3 4 1 5 2
PORPOISE 4 3 5 1 2
BAT 3 4 5 1 2 3 4
HUMAN 5

9. Morphological Convergence
Convergent evolution
Analogous structures: evolved from different ancestor (not similar in structure) but serves the same purpose (same environmental pressures)

10. Vestigial Structures
Structures that were present in the ancestor and had a function – but is no longer functional in the modern organism
Example snakes have tiny pelvic bones shows that the ancestor of the snake could walk
Humans have a tail bone, appendix which were functional in the ancestors

11. Comparative Development
During development, each animal or plant proceeds through a series of changes in form
Similarities in these stages are clues to evolutionary relationships

12. Comparative Development

13. Comparative Biochemistry
Kinds and numbers of biochemical traits that species share is a clue to how closely they are related
All life contains DNA, makes proteins using RNA and similar biochemical processes
More similarity means species are more closely related

14. Comparing Proteins
Compare amino acid sequence of proteins produced by the same gene
Human cytochrome c (a protein)
Identical amino acids in chimpanzee protein
Chicken protein differs by 18 amino acids
Yeast protein differs by 56

15. Speciation & Natural Selection
Natural selection can lead to speciation
Speciation can also occur as a result of other microevolutionary processes
Genetic drift
Mutation
“Species are groups of interbreeding natural populations that are reproductively isolated from other such groups.” Ernst Mayr