BIOLOGY 1M03 Lecture : 1MO3_Chapter 10.docx
11 Jun 2013
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Document Summary
During the miocene, the earth"s temperature began to fall. This global cooling caused two important changes in the climate of the african tropics. The total amount of rain that fell each year declined: rainfall became more seasonal, so there were several months each year when no rain fell. As the tropical regions of africa became drier, moist tropical forests shrank and woodlands and grasslands expanded. Changes brought about through generations of natural selection allowed a few species to move down from the trees, out of the rain forests, and into the woodlands and savannahs. Six m. y. a, climate and geographic change led to the evolution of hominins. Cooling, less rain, rain seasonality, woodland and savannah spread. These creatures were different from any of the miocene apes in two ways. This shift to bipedal locomotion led to major morphological changes in their bodies and new food became available.
