1. Comparative Anatomy Notes

2. Comparative Anatomy
- is the study of similarities and differences among structures of living species.

3. Homologous Structures
- are body parts of organisms that are similar in structure and position but different in function.

4. Look at what is the same and what is different…

5. Analogous Structures
- are body parts that perform a similar function but differ in structure.

6. Notice the wings are very different, but both are used to fly…

7. Vestigial Structures
- are body parts that have lost their original function through biologic evolution.

8. Whales have a number of vestigial structures that would have been fully functional in their land-living ancestors. These include the pelvic girdle, hind limbs and finger muscles.

9. Vestigial Structures in Whales
Whales have a number of vestigial structures that would have been fully functional in their land-living ancestors.
These include the pelvic girdle, hind limbs and finger muscles.

10. Vestigial Structures in Humans
Charles Darwin listed a number of human vestigial features in his book The Decent of Man (1890).
Muscles of the ear
Appendix
The tail bone
Body hair
Wisdom teeth

11. Q.1 Infer: What is the function of the bones in bats that are homologous to finger bones in humans?
Q.2 Infer: Why does a vestigial pelvis show that the ancestors of the modern whale once had legs?
Q.3 How do Homologous Structures and Vestigial Structures provide evidence for biologic evolution?

12. Q.4 Infer: Based on these notes and the evidence you see here, which animal do you think we (humans) are most closely related to – the chicken or the bat?