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4/4- The Australopithecines-approx. 4-1 million years ago-adaptive radiation- diverse group of species. “robusts & graciles”-some with dietary specializations-robust forms went extinct-through this period- not much change in brain size-successful for more than 3 million years- Trends-evolution of earliest hominids resulted in a diverse group of species-change in facial structure reflected dietary specialization-no large change in brain sizeAustralopithecus anamensisKenya. 4.2-3.9 MYAAustalopithecus afarensisbipedalism, sexual dimorphism (different size in male and female), and climbing adaptiondid they spend time climbing in trees? Curved hand and foot bones with marked muscle attachments.Australopithecus (Kenyanthropus) platyopsKenya, 3.5 MYAbroad face, small teethRobusts: megadontia (big teeth) and large chewing musclesAustralopithecus aethiopicusKenya, 2.5 MYAAustralopithecus boiseiEast Africa, 2.3-1.2 MYA4-5 feet tall, first specimen found by Mary Leakey. The teeth behind the canines are larger than any other hominids, faces are really flat.Australopithecus robustusSouth Africa, 2MYA.3-4 feet tall, weighed about 70-80 lbs. large brain size.Australopithecus garbiEthiopia, 2.5 MYA. First maker of tools. On other mammal bones they found in the same layer as these bones, they found cut marks, probable evidence of stone tool use. These monkeys made oldowan, first stone tools. Also used for digging.Significance of robust hominids specialized chewing adaptions:-successful for about 1 million years-selected for consuming difficult-to-process foodsBehavior: habitat: mixed grasslands, woodlands, forests-vegetarians- omnivores. Seeds, roots, nuts-tool maker? I.e. may have made stone tools. Not long fingers for climbing so maybe hands made for tool making. Spending less time in trees-social lifeAustralopithecus africanusSouth Africa, 3.0-2 MYA. Larger teeth than afrencis, body size similar to chimps, -“the taung child” found in 1924 by Raymond dart, down in the taung region. Described as a hominid based on features of the brain and the teeth. Other experts denied it being a hominid until 1950s. Bipedal. When first found thought it was 6 years old, but it is now known it is 4 years old. The Piltdown Hoax1912, Sussex, England. Ideology trumps science for 40 years.Believed to be missing link between humans and our ancestors. Brain looked like human brain, jaw was an ape jaw. Discovered it was a modern human cranium & orangutan jaw in 1953.Review: Australopithecus4-1 million years ago we had austropithecus. Adapted raditation- we have examples all over African continent. Very diverse group of species in this one genus. 2 primary shapes, robusts and graciles. Some dietary specialization. Robust ultimately became extinct. Successful and adaptive for more than 3 millionyears.4/9- Trends in early Homo & Homo erectus- -large jump in brain size-extensive meat eating-use of controlled fire-modern human body form-migration out of Africa -colonization of Asia- Homo habilisEast and South Africa, 2.0-1.6 MYAstone tools, name translates to “handy man”, smaller teeth, larger brain than Australopithecus. First found by Louis Leakey in tuzinia. - Oldowan toolseast and South Africa, 2.5 MYA-advent of biocultural evolution?- Homo erectus-morhologically diverse-smaller teeth than homo habilus-skeleton more robust--Africa -“nariokotome boy” 1.6 MYA. Some suggested his skeleton was more efficient at walking than modern humans are. - Homo rudolfensis. Originally considered to be a homo habilis but it has a larger braincase, longerface & larger molar & premolar teeth. 4/11, Film Notes- Fossils guarded in a vault in Kenya. One fossil found recently is of human ancestor like no other. Put together a skull, oldest human ancestor.- Some 100 MYA, apes lived in an ape’s paradise, then some 7-8 MYA apes disappeared. There a few survivors from planet of the apes in modern day.- Humans are way more intelligent than any other animals so we must have had a different evolution process than them. - Big-brained theory of human evolution: In the last 7 million years, an ape had evolved to have a slightly bigger brains, he produced apes with gradually bigger brains that evolved into humans.- Louis Leakey lived in Africa for 15 years looking for this big brained ape. He figured its brain size would be 600 cubic centimeters. When leakey got sick he passed his search down to Richard leakey- After 4 years searching, they found a few fossils. It put together a skull; it was skull of an ape likecreature, not an antelope like they thought. Skull was called “1470”- In 1974, another researcher Don Johansson found many pieces of bone, almost the entire skeleton of a 3 MYO ape like creature. They named the skeleton Lucy, after a song. Classified as an Australopithecus, after more research it became clear she was a human ancestor because of her one clear human characteristic: the way she walked, she walked on 2 legs not 4. They also found Lucy’s footprints in 1976. They are the same age as Lucy and the same size as her feet. The footprints showed us a Australopithecus walked on two legs, in a manner that was similar tohumans- But Lucy’s brain was too small, about the size of an American softball, about 1/3 size of a humanbrain. 1470’s brain was twice the size of Lucy’s, it was impossible for brain size to double in 100,000 years.- So the 2 skeletons were dated again. Lucy was over 3 million old, but it turns out 1470 was only 2 million years old. So 1470 could be descended from Lucy.- Killed idea that earliest ancestors would have a big brain- Stage one- by standing up our front legs became hands. To carry things, to use tools.- Larger brains lead to primitive culture and ways of better communication. - Evolution family tree- It seemed that Lucy had evolved without any adaptive radiation, no other fossils were found that walked on 2 legs- Weird thing about fossils form 6-8 MYA, the end of the planet of the apes. It seemed that there had been a radiation of new forms. At the end of the planet of the apes, there had been an ecological revolution. There had been a mass extinction, as forests were replaced by grassland; new species came who could adapt to the new world, the grass dwellers. - The reason Lucy was so special is because she had not evolved from the grass dwellers, it seemed like she evolved out of nothing which was absurd.- 3 ½ MYA there as only one possible human ancestor, Lucy. - A skull was


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NAU ANT 101 - The Australopithecines

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