HUMAN EVOLUTION: GENUS HOMO

1. HUMAN EVOLUTION: GENUS HOMO

2. Time-Line of Hominid Evolution:5 Adaptive Radiations • First Adaptive Radiation: 6-7 mya in the late Miocene, potential last common ancestors • Second Adaptive Radiation: 4-5 mya in early Pliocene, first true hominids • Third Adaptive Radiation: 3-4 mya in middle Pliocene, more hominids • Fourth Adaptive Radiation: 2-3 mya in late Pliocene, more & “robust” hominids • Fifth Adaptive Radiation: 2-1.8 mya in late Pliocene & early ice age, genus Homo

3. Rise of the genus Homo • Earliest fossils from same African sites as Australopithecines • Most date between 2.4 and 1.8 mya • Homo habilis means “handy man” • Growing consensus that there may have been 2 or more species of Homo living at the same time by about 2 mya

4. 6 SPECIES OF GENUS HOMO • Homo habilis • Homo ergaster • Homo erectus • Homo antecessor (“archaic” Homo sapiens) • Homo heidelbergensis (“archaic” Homo sapiens) • Homo neanderthalensis

5. Cranial capacity for Genus Homo

6. Homo habilis http://www.archaeologyinfo.com/homohabilis.htm

7. 1. Homo habilis • 2.3-1.5 mya • East Africa (Kenya, Tanzania, Ethiopia) & southern Africa • Increased brain size (680-800ml) • Stone tools

8. Homo habilis

9. Homo habilis at Olduvai Gorge, Tanzania Skeletal remains discovered at Olduvai Gorge in 1986 by Don Johanson revealed limb sizes and proportions nearly identical to australopithecines Brain size & face showed advances towards more human-like form

10. Homo ergaster http://www.archaeologyinfo.com/homoergaster.htm

11. 2. Homo ergaster • 1.8-1.6 mya • Lake Turkana, Kenya • Increased Brain Size (800-880 ml) • Thinner Skull with smaller facial bones (than Homo erectus)

12. Turkana Boy Skeleton • 90% of skeleton of adolescent male found west of Lake Turkana in the mid 1980s • 1.6 mya, very modern skeleton, similar to that of fully modern human

13. Homo erectus http://www.archaeologyinfo.com/homoerectus.htm

14. 3. Homo erectus • 1.8 mya – 33,000 ya • First hominid to migrate out of Africa! Africa, then Russia, China, Java, Italy, etc. (p. 270-71) • 50% increased brain size (900-1600 ml) • Fire, clothing, shelters, cooking

15. Homo erectus Facial Morphology

16. EXAMPLE: Peking Man Reconstruction

17. Archaic Homo sapiens • Hominids with larger brains & more modern cranial features than classic H. erectus • Recently divided into Homo antecessor & heidelbergensis • Taxonomy is problematic: some fossils could be H. erectus, others could be direct ancestors of later Neanderthals or pre-modern forms of H. sapiens AFRICAN ARCHAICS Kabwe, Zambia Bodo, Ethiopia EUROPEAN ARCHAICS Arago, France Petroloma, Greece

18. 4. Homo antecessor • 780,000 ya • Gran Dolina, Spain (oldest fossil humans in EU!) • Increased Brain Size (1000 ml) • Direct ancestor of H. heidelbergensis & H. neanderthalensis (?)

19. Homo antecessor • Mixture of "archaic" and "modern" traits, with especially modern-looking mid-face • Other features are not unique & could be considered a form of European H. erectus

20. 5. Homo heidelbergensis • 130,000 ya – 700,000 ya • Germany, China, Ethiopia, Greece, Hungary, Zambia, etc. (p.289) • Increased Brain Size (1000-1400 ml) • “Prepared Core” tools, wooden spears, dealt with changing environments

21. The Steinheim Cranium The Steinheim specimen excavated in the 1930s from Germany 1st archaic cranium discovered in Europe

22. Homo neanderthalensis http://www.archaeologyinfo.com/homoneaderthalensis.htm

23. 6. Homo neanderthalensis • 28,000 ya – 225,000 ya • Belgium, Croatia, Germany, France, Iraq, Israel, Italy (p.297) • Increased Brain Size (1200-1700 ml) • “Retouched flakes” (tool use), big game hunters, buried dead, cave art, early language?, compassion

24. Original Neanderthal Skullcap

25. Neanderthal Features

26. Neanderthal Adaptations

27. Modern Human Regional Variation African European-SW Asian East Asian Australian

30. Out of Africa (Single Region) • About 130,000 years ago, the first anatomically modern Homo sapiens evolved in East Africa (probably from H. erectus) • then migrated out of Africa to Europe, Asia, and the rest of the world. • At this point, H. sapiensmay have interbred with or out-competed other existing species, such as H. erectus and H. neanderthalensis.

32. Multiregional Hypothesis • 1.8 mya, Homo erectus evolved in East Africa and then began to migrate to Europe and Asia (due to lack of water and shelter) • A very successful species, H. erectus survived until 33,000 years ago! So…the Multiregional hypothesis argues that modern H. sapiens evolved from the differentH. erectus stocks in different regions (continents) at the same time. • After H. sapiens evolved in these different regions, may have been interbreeding, thus sharing of genes.

34. Compromise (Mostly Out of Africa) • About 130,000 years ago, the first anatomically modern Homo sapiens evolved in East Africa (probably from H. erectus) and then migrated out of Africa to Europe, Asia, & rest of world. • At this point, H. sapiens did interbreed with members of other species (H. erectus & H. Neanderthalensis)

42. Recent Research: “Mungo Man” • Part of mDNA extracted recently from bones of a 60,000 year old modern Homo sapiens skeleton found in 1974 on the shores of Lake Mungo in Australia • Oldest DNA extracted from a human so far! • Comparison of this DNA with that of 9 other ancient Australian skeletons, 2 Neanderthals, and 3,453 contemporary people from around the world indicates: "Mungo Man" had a unique genetic marker • Indicates that a now lost genetic line of modern Homo sapiens existed in Australia BEFORE arrival of later Australian Aborigines • This evidence provides significant support for rejecting the "out of Africa" complete replacement model of modern Homo sapiens evolution