While we can learn alot about our evolutionary heritage by studying the anatomy, genetics and behavior of living primates and ourselves, only the fossil record can provide:

• direct evidence of life in the past, including extinct species with no living counterparts
• documentation of the sequence and patterns of evolutionary changes
• evidence for timing of evolutionary events, and therefore the rates of evolution

What are fossils? Mineralized remains or impressions of ancient lifeforms, including hardparts (e.g. petrified wood and bone) and softparts (e.g. brain endocasts, footprints, leaf impressions)

Burial in undisturbed sediments is necessary for fossilization... sedimentary environments include river and lake basins, and airborn sediments such as dust, volcanic ash etc

How to date fossils?

• Relative dating techniques, based on uniformitarian principles of geology (e.g., stratigraphy, superposition)
• Absolute dating techniques (e.g. radiometric techniques such as K/Ar dating (to date volcanic sediments, half-life 1.3 billion years old)

Geological Time Scale: (WWW links to UC Berkeley paleontology museum exhibits)

Geological Era	Geological Epoch	Time periods	Evolutionary Event
Cenozoic "Age of Mammals"	Holocene	10,000 years ago to present	spread of agriculture and rise of civilizations
	Pleistocene	1.8 million years ago to 10,000 years ago	hominids leave Africa modern humans evolve complex societies develop
	Pliocene	5-1.8 mya	first hominid fossils and first artifact sites
	Miocene	22.5-5 mya	abundant fossil apes in Old World hominid split from apes in Africa
	Oligocene	37-22.5 mya	Fayum site
	Eocene	53-37 mya	abundant fossil evidence for early primates, including Prosimians and Anthropoids
	Paleocene	65-53 mya	? primate origins?
Mesozoic "Age of Dinosaurs"		65-225 mya	first mammals
Paleozoic		570-225 mya
Pre-Cambrian		before 570 mya	early life

Earth History & Primate Fossil Record:

Plate tectonics drives continental drift. Evolutionary implications:

• separation of continents causes changes in climate (global cooling)
• first primate fossils found in North America and Europe in Eocene when these areas were tropical (close to equator)
• South America isolated and colonized by Anthropoid monkeys in Eoceneonly after they first evolve in Africa... Old World and New World monkeys separated for over 37 million years
• late Eocene and early Oligocene fossils mark origins of Prosimian lineages, and first Anthropoid primates
• Fayum site, Egypt (33-35 mya) contains several species of early Anthropoid, including Aegyptopithecus, which may be ancestral to both monkeys and apes. Site was tropical swamp forest at the time.

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WWW links to climatic change and earth history:

• A Virtual Field Trip (400 million years of geological change)
• Ice Age Climate
• Greenhouse Lessons from the Geologic Record
• Ocean and Ice Cores:
• The Ocean Drilling Program (ODP)
• The GISP2 ice core record--paleoclimate highlights
• General climatology sites:
• Global Change - Electronic Edition
• Climate and Radiation - NASA/Goddard Space Flight
• Smithsonian Hologlobe

WWW links to fossil primate sites:

• UC Berkeley Paleontology Museum
• Tree of Life

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Last updated: 1 March 2000
URL: http://www.indiana.edu/~origins/teach/A105/lectures/A105L12L13.html
Comments: sept@indiana.edu
Copyright 1995, 1996, 1997 Jeanne Sept

do not reproduce without prior written permission