Chapter 5

1. Chapter 5 Macroevolution: Processes of Vertebrate and Mammalian Evolution

2. Chapter Outline • The Human Place in the Organic World • Principles of Classification • Definition of Species • Vertebrate Evolutionary History: A Brief Summary

3. Chapter Outline • Mammalian Evolution • The Emergence of Major Mammalian Groups • Processes of Macroevolution

4. The Human Place in the Organic World • Classification groups life forms into categories showing evolutionary relationships. • Example - human classification • Kingdom: Animalia • Subkingdom: Metazoan • Phyla: Chordata • Subphyla: Vertebrata • Class: Mammalia

5. Taxonomic Concepts • Homologies - structures shared through descent from a common ancestor. • Analogies - structures used for the same function that developed independently and are not the result of common descent. • Homoplasy - the process by which similarities can develop in different groups of organisms.

6. Cladistic Taxonomy Groups species according to shared derived characteristics: • Primitive traits reflect the ancestral condition. • Shared derivedcharacteristics are shared traits that weren’t present before the group's appearance.

7. Approaches to the Definition of Species

8. Evolutionary “Trees” Showing Development of Vehicles

9. Cladogram of Relationships of Birds, Dinosaurs, and Other Terrestrial Vertebrates

10. Evolutionary Relationshipsof Birds and Dinosaurs

11. 2 Approaches to Interpretations of Evolutionary Relationships

12. Speciation Model: Branching Evolution

13. Geological Time Scale

14. Geological Time Scale

15. Continental Drift

16. Geological Eras • Paleozoic • The first vertebrates appeared 500 m.m.y.a. • Mesozoic • Reptiles were dominant land vertebrates. • Placental mammals appeared 70 m.Y.A. • Cenozoic • Divided into two periods: Tertiary and Quaternary and 7 epochs: Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene and Holocene.

17. Mammalian Evolution • The Cenozoic era is known as the Age of Mammals. • After dinosaurs became extinct, mammals underwent adaptive radiation, resulting in rapid expansion and diversification. • The neocortex, which controls higher brain functions, comprised the majority of brain volume, resulting in greater ability to learn.

18. Major Mammalian Groups • Monotremes • Primitive, egg laying mammals • Marsupials • Infants complete development in an eternal pouch • Placental • Longer gestation allows the central nervous system to develop more completely

19. Early Primate Evolution • Primate origins began in the placental mammal radiation 65 m.y.a. • The earliest undoubted primates appear in the Eocene epoch. • Most of our knowledge of primate Oligocene evolution comes from a site in Egypt, the Fayum.

20. Fayum Forms: Possible Roots of Anthropoid Evolution • Apidium • Small, primate that may lie near or before the evolutionary divergence of Old and New World anthropoids. • Aegyptopithecus • Largest of the Fayum primates with a small brain, large snout, and none of the traits of Old World monkeys or the hominoids.

21. Miocene Fossil Hominoids • Marked by a spectacular hominoid radiation and could be called “the golden age of hominoids”. • Grouped geographically: • African forms (23-14 m.y.a.) • European forms (13-11 m.y.a.) • Asian forms (16-7 m.y.a.)

23. Lateral View of the Brain

24. Reptilian andMammalian Teeth

25. Genus and Species • Species is the most precise taxonomic level. • Genus is a group of species more closely related to each other than to species from another genus. • Members of the same genus share derived characteristics not seen in other genera.