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| Unit 8: Demos |
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Absolute vs. relative dating (1c) Continental
drift (2a) Conditions
necessary for species dispersal (3a/c) Convergent
evolution (5c) "Evolution in the Everyday World" from Scientific American (optional; see Blackboard for link) Primates (8a) Characteristics
that differ between apes and humans (9b) Latitudinal
trends in species diversity (12f) Go to Blackboard to access the "Rapid
Climate Change" article (courtesy of American
Scientist) Lake
turnover (download a .pdf file) |
Early Anthropoids: A Change of Environment Our anthropoid ancestors of 30-35 million years ago were still tree dwellers. But then about 20 million years ago, the Indian plate collided with Asia and thrust up the Himalayan range. The climate became drier and the forests of what is now Africa and Asia contracted. The result was an increased area of savanna habitat with fewer trees. Some of the major evolutionary changes leading to the origin of our species may have occurred as our ancestors came to live less in the trees. There was then an evolutionary modification of arboreal adaptations to a new way of life, walking on the ground in more open habitats. Based on the fossil record and comparisons of DNA between humans and chimpanzees, most researchers now agree that humans and apes diverged from a common hominoid ancestor only about 5-7 million years ago. From Campbell and Reece, Biology, 6th edition, 2002. |
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