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| Unit 8: Demos |
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Absolute vs. relative dating (1c) Continental drift (2a) Intermittent land bridges (2d) Did cracking continent trigger a deep freeze?: The break-up of a supercontinent may have caused a 'Snowball Earth'. (optional) Conditions necessary for species dispersal The Law of the Minimum and the Law of Tolerance (3b) Convergent evolution (5b) Confused by evolutionary trees? Check out Understanding Evolution. Primates (8a) Hominoid divergence (8d) A recent split of humans and chimps? (optional) (New!) Unique characteristics of primates (optional) Characteristics that differ between apes and humans (9b) Latitudinal trends in species diversity (12f) Life is faster in the temperate zones (optional) (New!) Rapid climate change article (courtesy of American Scientist) More on rapid global warming (optional) 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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