1. BIO 3220 COMPARATIVE VERTEBRATE ANATOMY Thank you to McGraw-Hill and Dr. Anil Rao (MSCD) for use of PowerPoint illustrations

2. Basic Definitions Anatomy Morphology

3. Phylogeny – Evolutionary History Paleontology Functional Adaptation Comparative Morphology Embryology

5. Homology Shared common ancestry Same embryonic precursor

7. Analogy Shared function Insect wings & bird wings Gills & lungs

10. Homoplasy/Homoplastic Organs Shared anatomy Generally, not homologous E.g. Insect wings vs. leaf

12. Key Points Homology Analogy Homoplasy

13. Form vs. Function Function, then form – Darwin’s Theory of Natural Selection – Adaptation Form, then function – Preadaptation

14. Evolution Random chance mutations, coupled with geographic isolation leads to… Change in gene frequency in a population

15. Divergent Evolution Related Present species evolved from common ancestor

17. Convergent Evolution Not closely related Dissimilar features evolved to become similar features

20. Parallel Evolution Related & Isolated Corresponding features undergo equivalent changes in isolated environments

21. Organic Evolution Present day species are descendants of previous species Changes that have taken place in plants & animals over time

22. Vestigial Structures Phylogenetic remnant Better developed in ancestor E.g. pelvic girdle in python

23. Key Point Can you think of a vestigial structure in humans?

24. Rudimentary Structure More developed in descendant E.g. neck, ear

25. Ontogeny An individual’s life history Fertilization to death Influenced by environment as well as genetics Structures earliest to develop are likely the oldest phylogenetically

26. Heterochrony Paedogenesis – Gonads develop quicikly Paedomorphosis – Immature features of ancestor become features of future SPECIES Neoteny – Immature features are retained as an adult in the INDIVIDUAL

27. paedomorphosis