1. Evolution:
A change in a population over time

2. Causes of Evolution:
Natural Selection
Migration
Mutation

3. What is Natural Selection?
Survival of the ‘fittest’
Occurs through INHERITED adaptations

4. What is migration? Movement of animals from one area to another.
Usually a response to changes in temperature, food supply, or the amount of daylight
Two types: emigration and immigration

5. What is mutation?
Permanent alteration of the DNA or genetic material of an organism

6. How can we tell that populations are evolving?
Talk with your group…

7. How can we tell that populations are evolving
How can we tell that populations are evolving? 3 Evidences of Common Ancestry in Evolution:
1. Fossils
2. Anatomy
3. Biogeography

8. 3 Evidences of Evolution
1. Fossils- provide a record of early life even though fossil records are incomplete. The fossil record identifies organisms throughout the geologic time scale.

9. Archaeopteryx

10. Which fossil would be the oldest?
Which would be youngest, fossil 1 or fossil 2?

11. 2. Anatomy- structural similarities show organisms evolved from a common ancestor
Homologous structures- structural features with a common evolutionary origin. They are similar in arrangement and/or function
Analogous structures- structures that do not have a common ancestry, but have similar functions (not structure)
Vestigial structures- a structure that is still present, but is no longer needed or used. (tailbone, appendix)

13. Analogous Structures
The wings of pterosaurs (1), bats (2) and birds (3) are analogous: they serve the same function and are similar in structure, but each evolved independently.

14. Vestigial Structures Blind Cave Lizards The Human Appendix
Wisdom Teeth in Humans
Hind Leg Bones in Whales
The Wings on Flightless Birds

15. 3. Biogeography –geographical distribution of plants and animals
Geographical distribution of a species
Related organisms occur in the same geographic area
Most similar to nearest neighbor

17. Review: Comparing closely related organisms:
Dendrograms:
Which organisms would be most genetically similar?
Which organisms would have the most genetic differences?

18. Review: Comparing closely related organisms:
Cladograms:
What trait do Ray-finned fish share with Amphibians?
Create an example of a discovery that would challenge the validity of this cladogram.