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Early Hominids

8. Early Hominids. Anthropology: The Exploration of Human Diversity 11 th Edition Conrad Phillip Kottak. Early Hominids. Chronology of Hominid Evolution The Earliest Hominids The Varied Australopithecines The Australopithecines and Early Homo Oldowan Tools.

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Early Hominids

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  1. 8 Early Hominids Anthropology:The Exploration of Human Diversity 11th Edition Conrad Phillip Kottak

  2. Early Hominids • Chronology of Hominid Evolution • The Earliest Hominids • The Varied Australopithecines • The Australopithecines and Early Homo • Oldowan Tools

  3. Chronology of Hominid Evolution • Lower Pleistocene (2 to 1 m.y.a.): late Australopithecus; early Homo • Middle Pleistocene (1 m.y.a. to 130,000 B.P.): Homo erectus • Upper Pleistocene (130,000 to 10,000 B.P.): modern Homo sapiens • The Pleistocene (2 m.y.a. to 10,000 B.P.) the epoch of human life

  4. Chronology of Hominid Evolution • Glacials separated by warm periods called interglacials • Ice sheets advanced and receded several times during the last glacial, The Würm (75,000 to 12,000 B.P.) • Several ice ages, or glacials, during Pleistocene

  5. The Earliest Hominids • Lived during late Miocene, between 5 and 5.8 million years ago • Eventually evolved into Pleistocene hominids known as australopithecines and, ultimately, to Homo • Ardipithecus and Kenyanthropus • Ardipithecus Apelike in size, anatomy, and habitat, living in a wooded area

  6. The Earliest Hominids • Views Kenyanthropus as an entirely new branch to the early human family tree. • Lucy may not be a direct human ancestor • Flattened face and small molars • Ardipithecus and Kenyanthropus • Complicating picture is discovery, which Maeve Leakey named Kenyantropus playtops • This species was identified in 1999 based on fossils from northern Kenya

  7. The Earliest Hominids • Dates and Geographic Distribution of the Major Hominid Fossil Groups • Insert Table 8.1

  8. The Earliest Hominids • Phylogenetic Tree for African Apes and Hominids • Insert Figure 8.1

  9. The Varied Australopithecus • A. afarensis (3.8? to 3.0 m.y.a.) • A. africanus (3.0? to 2.5? m.y.a.) • A. robustus (2.6 to 2.0 m.y.a.) • A. boisei (2.6? to 1.2 m.y.a.) • A. anamensis (4.2 m.y.a.)

  10. The Varied Australopithecus • Brain case is very small • Below neck, unquestionably human • Fossils indicate bipedalism • Australopithecus afarensis • A. afarensis lived between 3.8 and 3.0 m.y.a. • Similar in many ways to chimps and gorillas • Indicates common ancestry with African apes must be recent

  11. The Varied Australopithecus • Mixture of apelike and hominid features • Young probably depended on their parents for a relatively long time • May indicate a rudimentary cultural life • Australopithecus afarensis

  12. The Varied Australopithecus • Comparison of Dentition in Ape, Human, and A. afarensis Palates • Insert Figure 8.2

  13. The Varied Australopithecus • Comparison of Homo sapiens and Pan troglodytes (the Common Chimp) • Insert Figure 8.3

  14. The Varied Australopithecus • A Comparison of Human and Chimpanzee Pelvises • Insert Figure 8.4

  15. The Varied Australopithecus • A Comparison of the Skull and Dentition (Upper Jaw) of Homo and the Chimpanzees • Insert Figure 8.5

  16. The Varied Australopithecus • Facts about the Australopithecines Compared with Chimps and Homo • Insert Table 8.2

  17. The Varied Australopithecus • Most widely accepted theories stress advantages provided by bipedalism in a habitat increasingly dominated by drier, savanna-like conditions

  18. The Varied Australopithecus • Bipedalism is more energy efficient and therefore advantageous in a grassland, where resources are more dispersed than in forests. • Bipedalism exposes less body surface area to solar radiation • Bipedalism allowed them to see over long grass

  19. The Varied Australopithecus • Debate about relationship between graciles and robusts • Some argue graciles lived before (3 to 2.5? m.y.a.) and were ancestral to robusts (2.6? to 2.0? m.y.a.) • Others contend graciles and robusts were separate species that may have overlapped • Third model has both groups as part of a single polytypic species representing opposite extremes of variation • Gracile and Robust Australopithecines

  20. The Varied Australopithecus • Might have hunted small and slow-moving game • Gracile and Robust Australopithecines • Trend toward enlarged back teeth, chewing muscles, and facial buttressing, already noticeable in A. afarensis, continues in South African australopithecines Diet mainly vegetarian

  21. The Varied Australopithecus • In Robust australopithecines, chewing muscles strong enough to produce sagittal crest • Brain size increased only slightly between A. afarensis (430 cm3), A. Africanus (490 cm3), and A. robustus (540 cm3) • Gracile and Robust Australopithecines • Contrasts with Homo in front teeth less marked

  22. The Varied Australopithecus • Gracile and Robust Australopithecines • Australopithecine endocranial casts more human than apelike • Relied on rudimentary cultural means of adaptation

  23. The Varied Australopithecus • Skulls of Robust (left) and Gracile (Right) Australopithecines Showing Chewing Muscles • Insert Figure 8.6

  24. The Varied Australopithecus • Insert Figure 8.7

  25. The Varied Australopithecus • Palates of Homo sapiens and A. boisei • Insert Figure 8.8

  26. The Australopithecines and Early Homo • Ancestors of Homo split off and became reproductively isolated from later australopithecines between 3 and 2 m.y.a. Two clearly different sizes of teeth

  27. The Australopithecines and Early Homo • H erectus hunted and gathered, made sophisticated tools, and eventually displaced its sole surviving cousin species, A. boisei • Johanson and White propose that A. afarensis effectively produced two populations, one of which evolved into the other australopithecines, the other evolving into Homo habilis • Homo erectus had larger brain and re-proportioned skull

  28. The Australopithecines and Early Homo • 1985 discovery of the black skull (dated 2.5 m.y.a.), apparently an early A. robustus, made for more possible models of the divergence between Homo and Australopithecus

  29. The Australopithecines and Early Homo • Apelike jaw and relatively small brain (primitive features) • Sagittal crest on the top of the skull (previously associated with the relatively modern hyperrobusts, thus surprising to be found on a skull so old) • Surprising mixture of australopithecine features, particularly given its relatively early date

  30. The Australopitheciens and Early Homo • Shows that some anatomical features of hyperrobust australopithecines did not change very much • Black Skull Interpretations

  31. The Australopithecines and Early Homo • Richard Leakey found skull KNM-ER 1470 at site of Koobi Fora in 1972 • The skull exhibits a mixture of Homo and australopithecine features • Unusual combination of large brain and very large molars • Some researchers date the skull to 1.8 m.y.a; others date it to 2.4 m.y.a. • H. Rudolfensis and H. Hablis

  32. The Australopitheciens and Early Homo • Some scholars believe KNM-ER 1470 belongs to its own species, Homo rudolfensis • Others argue that KNM-ER 1470 belongs to H. habilis • Some researchers believe KNM-ER 1470 lived earlier than H. habilis • H. Rudolfensis and H. Hablis • KNM-ER 1470 Interpretations

  33. The Australopithecines and Early Homo • Others think that they lived at the same time. • Only sure conclusion is several different kinds of hominid lived in Africa before and after the advent of Homo • H. Rudolfensis and H. Hablis • KNM-ER 1470 Interpretations

  34. Oldowan Tools • Stone tools consist of cores and flakes • Core-piece of rock from which flakes are removed • Chopper-tool made by flaking the edge of such a core on one side • Oldest tools from Olduvai are about 1.8 million years old Oldowan pebble tools represent world’s oldest formally recognized stone tools

  35. Oldowan Tools • Anthropologists debate the identity of earliest stone tool makers Very likely that one kind of australopithecine made and habitually used stone tools along with Homo habilis

  36. Oldowan Tools • In 1999, a new hominid species, A. garhi, found in Ethiopia associated with stone tools and the remains of butchered animals • Added new species to human family tree • Demonstrated the thigh bone elongated one million years before the forearm shortened to create current human proportions • Showed early stone tools designed at getting meat and marrow from big game • A. Garhi and Early Stone Tools

  37. Oldowan Tools • By 1 m.y.a. single species of hominid (H. erectus) rendered other hominid forms extinct and expanded the hominid range to Asia and Europe • A. Garhi and Early Stone Tools • Cultural abilities developed exponentially with Homo’s appearance and expansion

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