Human Evolution

1. Human Evolution

2. The Evolutionary Path to Humans Begins with Early Primates • The story of human evolution begins around 65 M.Y.A. • This time marks the explosive radiation of a group of small, arboreal mammals called the Archonta • they were likely nocturnal and were arboreal and insectivorous • their radiation gave rise to different types of mammals, including • bats, tree shrews, and primates • primates are the order of mammals that includes humans

3. The Evolutionary Path to Humans Begins with Early Primates • Primates are mammals with two distinctive features that allowed them to succeed in the arboreal, insect-eating environment • grasping fingers and toes • the first digit in many primates is opposable and at least some of the digits have nails • binocular vision • this permits the brain to judge distance precisely

4. Origin of Anthropoids • Anthropoids are higher primates and include monkeys, apes and humans. • Almost all diurnal (active during the day). • Evolution: • Eye changes; • Larger brains; • Social interactions; • Long-term tending of their young to improve learning and brain development.

5. Early Primates - Traits • Common physical primate traits: • Dense hair or fur covering • Warm-blooded • Live young • Suckle • Infant dependence • Common social primate traits: • Social life • Play • Observation and imitation • Pecking order Common Primate Traits

6. The Evolutionary Path to Humans Begins with Early Primates • About 40 M.Y.A. the earliest primates split into two groups • prosimians • surviving representatives today include the tarsiers, lemurs, and lorises • most are nocturnal • anthropoids • these higher primates included monkeys, apes, and humans • the early anthropoids, now extinct, likely evolved in Africa

7. Figure 27.1 A primate evolutionary tree

8. Hominin Diversity: Fossil Sites in the Old World

9. The Evolutionary Path to Humans Begins with Early Primates • The monkeys are a very successful group of primates • New World monkeys • South American descendants of African ancestors • all are arboreal, have flat spreading noses, and prehensile tails • Old World monkeys • descendants of the ancestral anthropoids that remained in Africa • none have prehensile tails • include both ground-dwelling and arboreal species

10. How the Apes Evolved • Hominoids evolved from anthropoid ancestors • hominoids are comprised of the apes and the hominids (humans and their direct ancestors)

11. 27.2 How the Apes Evolved • Studies of ape DNA have revealed much about how living apes evolved • Asian apes evolved first • gibbons diverged from other apes about 15 M.Y.A. • orangutans split off about 10 M.Y.A. • neither are closely related to humans • African apes evolved more recently (between 6 to 10 M.Y.A.) • these apes are the closest living relatives to humans

12. 27.2 How the Apes Evolved • Chimpanzees are more closely related to humans than gorillas are • chimpanzees diverged from the ape line less than 6 M.Y.A. • the genes of humans and chimpanzees have not had time to evolve many differences • humans and chimpanzees share 98.6% of their nuclear DNA • gorilla DNA differs from human DNA by about 2.3% • gorillas split off from the ape line around 8 M.Y.A.

13. How the Apes Evolved • The common ancestor of apes and hominids is thought to have been an arboreal climber • Much of the subsequent evolution of the hominoids differs with respect to locomotion • hominids evolved bipedal walking • anatomical features include S-shaped spine, bowl-shaped pelvis, lower limbs larger than upper limbs • apes evolved knuckle-walking • anatomical features include slightly curved spine, long pelvis, upper limbs larger than lower limbs

14. Evolution of Bipedalism • Anatomical changes • Neck (1), chest (2), lower back (3), hips and pelvis (4), thighs (5), knees (6), feet (7) • Theories • Tool use and bipedalism (Darwin/Washburn) • Energy efficiency and bipedalism (Isbell/Young) • Radiator theory (Falk) • Body temperature and bipedalism (Wheeler) • Habitat variability and bipedalism (Potts) • Reproduction and bipedalism (Lovejoy) • Canine reduction and bipedalism (Jolly) (Click for interactive skeleton)

15. Figure 27.3 Walking upright has evolved many times among vertebrates

16. A comparison of ape and hominid skeletons

17. The first of our genus: Early Homo

18. Hominin Evolution • Major Homo advances: • Brain size • Better bipedalism • Hunting • Fire (H. erectus) • Tools • Oldowon (H. habilis) • Acheulean (H. erectus) • Mousterian (H. heidelbergensis) • Solutrean (H. sapiens) • Built shelters (H. heidelbergensis) • Clothing (H. neandertalensis) • Language (Neandertals?)

19. 27.5 African Origin: Early Homo • The first humans evolved from australopithecine ancestors about 2 million years ago • Homo habilis • it had a larger brain volume than Australopithecus but was similarly short in stature • called “handy man” because of its association with tools.

20. Figure 27.6 Homo habilis

21. Homo habilis • 612 cc brain • 2.3 - 1.6 mya • first toolmaker • prognathic face, brow ridge • probable meat-eater • possibly arboreal • discovered in 1960 by Leakeys Artist rendition of H. habilis. ER-1813 – Homo habilis

22. Oldowan Tool Industry The Oldowan is the first known industrial complex in prehistory. It takes its name from Olduvai Gorge, Tanzania Oldowan tool use is estimated to have begun about 2.5 million years ago (mya), lasting to as late as 0.5 mya. It is thought that Oldowan tools were produced by several species of hominids ranging from Australopithecus to early Homo. • Chopper with simple edge • Chopping tool • Unretouched biface

23. H. habilis vs. H. erectus • Finds in east Africa indicate that Homo habilis was not very different from the australopithecines in terms of body size and shape. • The earliest Homo erectus remains indicate rapid biological change. • H. erectus was considerably taller and had a larger brain than H. habilis.

24. Figure 27.7 Homo ergaster

25. 27.5 African Origin: Early Homo • Too few fossils have been found of early Homo to explain with certainty the evolution of Homo • if two species are accepted, then it would appear Homo underwent an adaptive radiation • because of its modern skeleton, Homo ergaster is thought to be the most likely ancestor to later species of Homo and is often lumped with Homo erectus

26. 27.6 Out of Africa: Homo erectus • Homo erectus is definitely a true human and has been supported by many specimen finds, including those of Java Man and Peking Man • Homo erectus was taller and had a larger brain than H. habilis • the shape of the skull interior suggests that it was able to talk • it was a social species

27. Homo (ergaster) erectus • 1891 - Eugene Dubois discovers H. erectus in Java • Dubois calls it Pithecanthropus erectus initially, also dubbed “Java Man” • Dates from 1.9 mya to 27,000 years B.P. • 994 cc brain size (compare to 612 for H. habilis) • Acheulean tool industry • All finds in E. Asia are H. erectus, everywhere else is called H. ergaster. Photograph of Nariokotome boy, an early Homo erectus found near Lake Turkana, Kenya.

28. Turkana Boy Homo ergaster Turkana Boy: a nearly complete skeleton of an 11 or 12 year old boy who died approximately 1.5 million years ago near Lake Turkana in Kenya by Kamoya Kimeu and Richard Leakey in 1984.

29. Why was H. erectus so successful? Less hair on body = wearing of furs, other clothing. Wearing of furs = ability to live further north. Quick adaptation to environment without physical changes. Culture is main reason H. erectus was so successful organization for hunting ability to protect against predators control of fire? possible campsites tools (Acheulean industry) Homo ergaster – 1.9mya to 27k yBP Distribution of H. erectus

30. Acheulean Tools • Acheulean tools are typically found with Homo erectus remains. • It was the dominant technology for the vast majority of human history and more than one million years ago it was Acheulean tool users who left Africa to first successfully colonize Eurasia.

31. Homo neanderthalensis • discovered in the Neander Valley (Tal) near Dusseldorf, 1856 • massive brain--about 1,400cc on average • large torso, short limbs, broad nasal passages • later remains show decrease in robustness of the front teeth and face, suggesting use of tools replaced teeth • retained occipital torus, some mid-facial prognathism Range of Homo neanderthalensis The skull of the classic Neandertal found in 1908 at La Chapelle-aux-Saints. First reconstruction of Neanderthal man. http://www.youtube.com/watch?v=5OJcS3y3mlI&feature=SeriesPlayList&p=39B8670A9074CF60&index=0 http://www.youtube.com/watch?v=CgEFoY-hoT4&feature=SeriesPlayList&p=39B8670A9074CF60&index=2 http://www.youtube.com/watch?v=pKs1Q7f1Uzg&feature=SeriesPlayList&p=39B8670A9074CF60&index=3 http://www.youtube.com/watch?v=o589CAu73UM&feature=SeriesPlayList&p=39B8670A9074CF60&index=5

32. Neandertal Culture • Homesites – In caves, also in the open (near rivers, framed with wood and covered with skins) • Burial – Is there evidence of purposeful burial and ritual? • Language – Could Neandertals talk or not? • Tools – Mousterian tradition Top: Reconstruction of Neandertal burial from Shanidar cave Bottom: Mousterian tools

33. What happened to Neandertals? • H. neanderthalensis coexisted with H. sapiens for at least 20,000 years, perhaps as long as 60,000 years • What happened? • Neandertals interbred with H. sapiens • Neandertals were killed off by H. sapiens • H. sapiens drove Neandertals into extinction by competition http://www.youtube.com/watch?v=IsSOcwY79ig&feature=related

34. Homo sapiens • Archaic – 150,000 to 35,000 years BP • Earliest members of the species Homo sapiens with different subspecies such as H.s. neanderthalensis or H. s. idaltu • Modern – 50,000 years BP to present • Fully modern behavior& anatomy becomes prominent. • Ritual burying; reproduced tools of bone & antlers; fishing (costal sites show evidence of fishing after 50k ya). • First hominids to reach Australia (language?). • Cultural universals emerge: art, music, religion. • Sometimes called Homo sapiens sapiens

35. Modern Homo Sapiens • Regional-Continuity Model (Milford Wolpoff, UMich) • Humans evolved more or less simultaneously across the entire Old World from several ancestral populations. • Rapid-Replacement Model (Chris Stringer, NHM London) • Humans evolved only once--in Africa from H. heidelbergensis ancestors--and then migrated throughout the Old World, • replacing their archaic predecessors. Also called the “Out of Africa” and “Killer Ape” hypothesis. http://www.youtube.com/watch?v=doF4sNrQtmg&feature=related http://www.youtube.com/watch?v=MIQNzbd4-RY

36. Upper Palaeolithic – Hotbed of Culture • 40 – 10k yBP • Shelters • 15,000 yBP Ukraine • Some made with mammoth bones • Wood, leather working; carpentry • Tools • From cores to blades • Specialization • Composite tools • Bow and arrow • Domestication of dogs • Gathering rather than hunting became the mainstay of human economies. Top: Straw Hut Left: Mammoth bone hut Bottom: Tool progression

37. Early H. sapiens Culture • Art • Traces of art found in beads, carvings, and paintings • Cave paintings in Spain and southern France showed a marked degree of skill • Female figurines • 27,000 to 22,000 years B.P. (Western Europe to Siberia) • Called “venuses,” these figurines depicted women with large breasts and broad hips • Perhaps it was an example of an ideal type, or perhaps an expression of a desire for fertility or abundance. Venus of Willendorf. Discovered in 1908 in Austria and dated to approximately 23,000 years ago.

38. Archaic H. sapiens Culture Cave paintings from 20,000 years ago at Vallon-Pont-d’Arc in southern France (left) and from Lascaux, in southwest France • Cave paintings • Mostly animals on bare walls • Subjects were animals favored for their meat and skins • Human figures were rarely drawn due to taboos and fears that it would somehow harm others http://www.youtube.com/watch?v=oSHKqX8_pqU&feature=related

39. The Hominid Family Tree • In 1995, hominid fossils dating 4.2 million years old were found in the Rift Valley of Kenya • they were assigned to the species Australopithecus anamensis • they represent an intermediate form between apes and A. afarensis • this species represents a base of the family tree for human evolution

40. The Hominid Family Tree • Scientists have taken two different approaches in classifying the species of Homo • “Lumpers” recognize three species of Homo, focusing on common elements among fossils and attributing the differences to diversity within the group • “Splitters” recognize at least seven species of Homo

41. Figure 27.5 A hominid evolutionary tree

42. African Origin: Early Homo • Homo rudolfensis • described from a specimen discovered in 1972 with a larger brain capacity than H. habilis • Homo ergaster • a species used to describe specimens that have a larger brain capacity than H. rudolfensis and a skeleton more like modern humans and less like australopithecines

43. Brain size increased as Homo evolved

44. Out of Africa: Homo erectus • The oldest specimen of H. erectus is from Africa, indicating that H. erectus arose in Africa • Homo erectus survived for over a million years, longer than any other species of human • Homo erectus disappeared about 500,000 years ago in Africa, but the species survived even longer in Asia

45. Homo erectus • 1891 - Eugene Dubois discovers H. erectus in Java • Dubois calls it Pithecanthropus erectus initially, also dubbed “Java Man” • finds in China called Sinanthropus • dates from 1.9 mya to 27,000 years B.P. • 994 cc brain size (compare to 612 for H. habilis) • Acheulean tool industry Photograph of Nariokotome boy, an early Homo erectus found near Lake Turkana, Kenya.

46. Why was H. erectus so successful? Less sexual dimorphism = possible pair bonds, marriage Less hair on body = wearing of furs, other clothing Wearing of furs = ability to live further north Quick adaptation to environment without physical changes Culture is main reason H. erectus was so successful organization for hunting ability to protect against predators control of fire? possible campsites tools (Acheulean industry) Homo erectus – 1.9mya to 27k yBP Distribution of H. erectus

47. Neandertal Culture • Homesites – In caves, also in the open (near rivers, framed with wood and covered with skins) • Burial – Is there evidence of purposeful burial and ritual? • Language – Could Neandertals talk or not? • Tools – Mousterian tradition Top: Reconstruction of Neandertal burial from Shanidar cave Bottom: Mousterian tools

48. What happened to Neandertals? • H. neanderthalensis coexisted with H. sapiens for at least 20,000 years, perhaps as long as 60,000 years • What happened? • Neandertals interbred with H. sapiens • Neandertals were killed off by H. sapiens • H. sapiens drove Neandertals into extinction by competition

49. Our Own Species also Evolved in Africa • Modern humans first appeared in Africa about 600,000 years ago • According to some scientists, there have been three species of modern humans • Homo heidelbergensis • Homo neanderthalensis • Homo sapiens

50. Our Own Species also Evolved in Africa • Homo heidelbergensis is the oldest known modern human • an Ethiopian fossil dates back to 600,000 years ago • it co-existed with H. erectus in Africa but had more advanced features • it had a bony keel running along the midline of the skull, a thick ridge over the eye sockets, and a large brain • its range included parts of Africa, Europe, and western Asia