The History of Our Tribe Hominini Textbook Part IV Pleistocene Epoch Chapter 16 Paranthropines

PART IV EPOCH THE EPOCH ( kya ) Figure East African grassland and a local . Photo by the author . The Epoch is commonly known as the Ice Age . The climate of Africa continued on the trajectory that began in the late and continued throughout the ( see Figures and ) While the was characterized as a period of global cooling , glacial advances , and dropping sea levels . the cold periods were interspersed with interglacial periods when the ice retreated and sea levels rose ( see , and IVA ) Even within glacial periods , the climate varied . Animals in northern areas that were not adapted to arctic conditions went extinct or moved south when temperatures dropped and vice versa . They pushed in and out of Africa . in response to those climatic pulses . i a ! It . Five Million Years of 45 Climate Change 30 From Sediment Cores i I I ' Millions of Years Ago Figure Global temperature fluctuations from ( through ( to present . Climate Change by Robert is licensed under . Elizabeth claims that there was a turnover in faunal populations in East Africa at , in response to climatic change . her Turnover Pulse Hypothesis , she finds evidence of an increase in ( animals like wildebeests and water buffalo ) and their predators and a decrease in 113

Ice Age Temperature Changes ) co I ( Low High 450 400 350 360 250 260 150 160 50 Thousands of Years Ago Figure Antarctic temperature changes during the last several glacial and cycles of the present ice age arid a comparison to changes in global ice volume . Ice Age Temperature by Robert is licensed under dwelling , corresponding to an increase in dry savanna environment ( see 1985 and publications ) Based on deep sea cores , we know that by , there was a definite increase in the of environment . Thus evidence from past flora and fauna supports the more robust dental anatomy of species that lived during the early , Au . Au . and . They would have needed stronger chewing abilities and thicker molar enamel to process more vegetation . Once the more gracile ( in term of their masticatory apparatus ) Homo species came on the scene , the East African would come to represent an example of niche ing . Fossil sites suggest that , habilis , and could have been sympatric ( overlapping geographic ranges ) Thus while Au . and survived by what might be termed masticatory brawn , the more Homo species used their brains and tools to consume a diet . We can thus see that were some of the colonizing species of the African savanna . 114

Temperature Difference ( Figure IVA Temperature reductions during last glacial maximum 18 kya . Robert is licensed under . 115 16 . The are three species of fossil that exhibited masticatory apparatus , as evidenced by their heavy faces and mandibles , huge molars , and muscle . They were included in the genus for many years , but the original genus invented by Robert Broom for the South African form , has been revived for at least two of the species . Chronologically , the earliest species was , and some researchers still assign them to . The second oldest is , and both Au . and are from East African sites . The South African and youngest species is . The last of the died out , after Au . first appearance in the fossil record . They were a very interesting and apparently ful group of animals that adapted to the changing African landscape by expanding their dietary niche . The geographic range of the eastern species stretched down the corridor from Ethiopia to , whereas the South African form is known only from South Africa . While it is thought that their preferred foods were similar to the more gracile forms , they could fall back on tougher and harder foods when resources became scarce . 117