Chapter 8, Processes of Macroevolution The Human Place in the Organic world Principles of Classification Definition of Species Vertebrate Evolutionary History

Chapter 8, Processes of Macroevolution Mammalian Evolution Early Primate Evolution Miocene Fossil Hominoids Processes of Macroevolution

The Human Place in the Organic World Classification into categories that show evolutionary relationships. Example - human classification – Kingdom: Animalia – Subkingdom: Metazoan – Phyla: Chordata – Subphyla: Vertebrata – Class: Mammalia

Processes of Speciation Allopatric -complete reproductive isolation Parapatric -partial reproductive isolation Sympatric - speciation occurs within a population with no necessary reproductive isolation.

Vertebrate Evolutionary History Paleozoic – First vertebrates appeared 500 m.y.a. Mesozoic – Reptiles were dominant land vertebrates. – Placental mammals appeared 70 m.y.a.

Vertebrate Evolutionary History Cenozoic Divided into two periods: – Tertiary and Quaternary Divided into 7 epochs: – Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene and Holocene.

Mammalian Evolution Cenozoic era is the Age of Mammals. Adaptations: Neocortex, controls higher brain functions, enlarged resulting in greater ability to learn. Heterodont dentition allowed mammals to process a wide variety of foods. Constant body temperature

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

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.

Miocene Fossil Hominoids 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.).

Miocene Hominoid Fossils: Conclusions 1. More closely related to ape-human lineage than Old World monkeys. 2. Mostly large-bodied hominids. 3. Improbable ancestors of any living form. 4. One lineage suggests a close evolutionary link to the modern orangutan.

Adaptive Radiation A species or group of species will diverge into as many variations as two factors allow: 1. Adaptive potential 2. Adaptive opportunities of the available zones.