EESC 1174 Lecture 11: EESC117401 (3-16-2016)
20 Jun 2016
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Past climate and humans: human evolution, started in east africa, evolutionary tree. Common ancestor of chimps and bonobos hominids split 6-8 million yeas ago. Australopithecus afarensis 4 million: small chimp size brains and projecting jaw. C. 1. long sharp canine teeth: emergence of genus homo (2. 9-2. 6) Homo habilis first maker of stone tools: 1. 9 homo erectus larger brains anatomically similar adapted to long distance running shoulder capable hand axes 1. 6. F: 600-20000, 3000-40 neanderthalensis, homo sapiens 200,000 years. How did african climate change through time: forest c3 photosynthesis - lower 13c/12c, grassland c4 photosynthesis - higher 13c/12c. C: long term drying in africa over last 3 million years tells you how tree filled or savanna grass like the landscape was. D. 1. more dust blowing off africa suggesting drying trend. Drying in africa in response to global cooling and ice ages: shorter term 20,000 year wet dry monsoon cycles due to orbital precession.
