1. Evidence for Evolution
Homologous Structures- features similar in structure, but appear in different organisms with different functions.
Analogous structures- structures similar in function, but are not similar in origin.
Vestigial structures – remnants of organs or structures that had a function in early ancestor
Embryological Evidence –share common ancestry based on similarities during larvae/fetus stage.

2. Homologous Structures (same origin, different function)- Divergent Evolution
Evidence for common ancestry can be observed in the limbs of mammals.

3. Analogous structures (same function, different origin)- Convergent Evolution
All of these organisms have wings for flight but it is NOT due to recent common ancestor. It is due to similar environmental pressures under which flight was adaptive.

4. Had function in ancestor but no longer serves significant purpose
Vestigial structures
Had function in ancestor but no longer serves significant purpose

5. What do furry animals do when they are afraid?

6. It’s a reflex!

7. Pilomotor reflex
We aren’t intimidating anyone with our pilomotor reflex!

8. Other human vestigial structures
Tail bone
Appendix
Wisdom teeth– our ancestors with larger jaws could actually fit theses teeth in their mouth. With no access to dental care, it is also likely that they would be in great need of a back up set of molars. They just cause people problems today, with many having to have them surgically removed. Such a disadvantage would surely be selected against in the wild. Some humans (like Ms. D!) don’t ever grow wisdom teeth.

9. Kiwi bird has vestigial wings
Whales have femurs (thigh bones) suggesting ancestors walked on land… hmm… they also breathe oxygen!

10. Paleontology-the study of fossils or extinct organisms.

11. Embryological evidence
Note the similarities at early stages of development

12. Calculating Allele Frequency (ratio of one allele to the total # of the alleles for that gene in the gene pool.)
Count the number of times an allele occurs in a gene pool
Divide by total number of alleles