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1 Biological Anthropology Biological evolution is the background for culture as a method of adaptation to physical environmental conditions. Human evolution.

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Presentation on theme: "1 Biological Anthropology Biological evolution is the background for culture as a method of adaptation to physical environmental conditions. Human evolution."— Presentation transcript:

1 1 Biological Anthropology Biological evolution is the background for culture as a method of adaptation to physical environmental conditions. Human evolution is a story of co- evolution: cultural and biological change reinforcing one another.

2 2 Basic Hominid Adaptations Bipedalism Orthograde posture Rotation and narrowing of the pelvis All were biological adaptations that provided some of our ancestors with unique reproductive advantages.

3 3 Orthograde apes Those advantages came before the increase in brain size that we associate with the development of humans. The earliest human ancestors, then, were orthograde apes.

4 4 Increase in Brain Size Development of the brain case in Australopithecus produced other advantages – an increase in the capacity for tool making, implying better communication skills. Note the italics. With Homo erectus, there is further expansion of the brain and greater control of lithic resources.

5 5 By the Middle Paleolithic, the Levallois method had transformed tool making into manufacturing. Levallois method With the development of H. sapiens sapiens, 40 kya, the point of “cultural take-off” was reached (Harris 1999).

6 6 Cultural Take-Off Major cultural changes prior to the take-off point were tied to changes in the skeleton. Since the Upper Paleolithic, cultural change has been independent of biological change – though biological adaptations continue.

7 7 The Idea of Evolution Carolus Linnaeus (1707-1778) publishes the first edition of Systema Naturae (1735). Eleven pages. The 13 th edition was published in 1770, with 3000 pages. Whales with mammals, and monkeys with humans No evolutionary scheme.

8 8 Georges-Louis Leclerc Georges-Louis Leclerc, Comte de Buffon (1707-1788). Discussed the similarities between humans and apes in his Historie Naturelle – 44 volumes (1749 – 1804). Anticipated Charles Lyell’s work by challenging the accepted age of the Earth.

9 9 George Cuvier (1769-1832) Established the field of vertebrate paleontology. Established the fact of extinction. In Discours sur les revolutions de la surface du globe, et sur les changemens qu'elles ont produits dans le regne animal (1825), Cuvier argued for catastrophism. A variety of catastrophism is the modern explanation for the Cretaceous-Tertiary (K-T) extinction event. (K-T) extinction event

10 10 Jean Baptiste Lamarck (1744-1829) Established the field of invertebrate zoology. Proposed a theory to account for variation in species, and hence, for evolution. His theory of inherited characteristics was wrong but Darwin credited Lamarck as having been the first to assert that laws govern the diversity of nature.

11 11 Malthus and Darwin Thomas Malthus (1766-1834). In his book, Essay on the Principle of Population as it affects the future improvement of society (1798), he proposed that resources grow arith- metically, while population grows geometrically.

12 12 Malthus and Darwin Malthus turned out to be wrong, but his insight about the struggle for resources across generations gave Darwin the idea for natural selection.

13 13 “In October 1838 … fifteen months after I had begun my systematic inquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long- continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The results of this would be the formation of a new species. Here, then I had at last got a theory by which to work“ (Darwin 1876).

14 14 Charles Lyell (1797-1875) Principles of Geology: being an attempt to explain the former changes of the earth's surface, by reference to causes now in operation, (1830-1833). The principle of uniformitariansim – that the forces shaping the Earth today were the same from the beginning of time.principle of uniformitariansim

15 15 Darwin was helped by Lyell's observations about the age of fossils in developing the reproductive advantage theory of biological evolution.

16 16 Darwin and Wallace Charles Darwin (1809-1882) Origin of Species by means of natural selection, or, The preservation of favoured races in the struggle for life (1859). Alfred Russel Wallace (1823–1913) was in Malaysia, writing papers offering the same theory of evolution that Darwin was developing. Darwin published first.

17 17 Darwin’s Breakthrough Here is the famous passage from p. 64 of the 1859 edition: “As more individuals are produced than can possibly survive, there must in every case be a struggle for existence, either one individual with another of the same species, or with the individuals of distinct species, or with the physical conditions of life.”

18 18 Gregor Mendel (1822-1884) Versuche über Pflanzenhybiden (1866) He planted a peculiar variety of ornamental plant at a monastery next to a typical specimen. His idea was to test directly Lamarck’s theory. The traits of all offspring conformed to those of the parent generation. And of course, there were Mendel’s peas.Mendel’s peas

19 19 The First Primates The Earth is about 4.5 billion years old.years old Life appears at the end of the Precambrian, ~540 million years ago. The Paleocene begins about 65 million years ago, with the disappearance of the dinosaurs, the rise of mammals and the development of the first primates.first primates

20 20 Mammalian Traits Distinctive mammalian traits include: constant body temperature postpartum development of helpless offspring internal reproduction and fertilization greater reliance on learned behavior

21 21 More Reliance on the Brain Cerebrum of more importance. In humans, the cortex is convoluted, like a wound coil, with specialized areas: frontal lobe for choice and decisions lower parietal lobe for associations and sensory data temporal lobe for memory lower frontal lobe for motor speech occipital lobe for visual acuity

22 22 Nonhuman Primates Linneaus identified primates as a separate family, with four genera: Homo, Simia, Lemur, and Vespertilio. Pan named in 1816; Gorilla in 1847. In 1863, Thomas Huxley’s book, Man’s Place in Nature contained a conclusion about the close relationship between African apes and modern humans.

23 23 Nails, claws, and trees Primates are mammals that climb by grasping – nails, not claws – the evolutionary correlate of arboreal adaptation, along with stereoscopic vision, a further increase in brain size, and a shortened snout. Remember: teleological explanations are not assumed.

24 24 Prosimians Two suborders: Prosimians and Anthropoids Prosimians include the lorises, tarsiers and lemurs of Asia and Africa. The special case of Madagascar. See Kottak’s discussion of this.Madagascar 65 mya

25 25 Anthropoids 40 mya – anthropoids have bigger brains, relative to body size than the prosimians, a shorter snout, and front-facing eyes enclosed in bone.anthropoids Two types: catarrhines (Old World monkeys and apes) and platyrrhines (New World monkeys) separated 35mya in the Oligocene.New World monkeys

26 26 Catarrhines and the Hominoids The catarrhines include circopithecoids and the colobines, as well as the hominoids. The hominoids include the hylobates, the pongids, the genus Pan, and the hominids.hominoids There is only one species of hominid today, H. sapiens sapiens.

27 27 Cercopithecines Cercopithecines (Old World monkeys) have smaller brains relative to body size than hominoids (apes and humans).Old World monkeys) Cercopithecines’ molars are bilophodont while those of the hominoids have several cusps.molars are bilophodont Cercopithecoids have tails. Hominoids have no tails. Prehensile tails are found only in New World monkeys.

28 28 Baboons Baboons are the largest of the monkeys. Sexual dimorphism: males reach 35kg, females reach 17kg Baboons: terrestrial, live on the open savannah, frugiverous and herbivorous. They do eat a little meat, but this feature is more important for the hominoids, especially Pan.

29 29 Hominoids and Hominids Three families within the superfamily: The hylobates include the gibbon and siamang of Southeast Asia. Brachiation Orangutans reach 80kg (males), 40kg for females The pongids include the chimps, gorillas, and bonobos. Hominids are us.

30 30 Chimps and Gorillas Chimps spend their days on the ground and their nights in trees and live in communities of 40-60. Gorillas reach 160kg (males), 80kg for females. Gorillas are herbivorous and sleep on the ground. They are at the top of the food chain and have no predators – except us.

31 31 Chimps and Humans Anatomical morphological data show the close relationship. Immunological reactions, amino acid sequences, and DNA maps show close association among the chimp, gorilla, and human. Best current estimate: humans split from the line leading to chimps and gorillas between 5-8 mya ago.

32 32 Summing up H. sapiens is some ways like all other animals, and in some ways unique. We share traits with all vertebrates – a spinal column – and we share traits with all mammals – constant body temp, for example – and we share traits with all primates, our closest relatives.

33 33 The traits we share with all primates are: prehensile hands mobility of arms through the shoulder stereoscopic color vision a small number of offspring born at one time, a long period of dependency and learning very large brains, relative to body size social organization.

34 34 As we get closer to humans in terms of DNA, we also share increased intelligence and increased social life. A distinctive feature of humans is our nearly complete dependence on learning. This implies a lot of social organization, and the use of tools, language, and culture.

35 35 Fossil Primates Oligocene anthropoids – Aegyptopithecus (33mya) had the Oligocene anthropoids 2-1-2-3 dental formula2-1-2-3 dental formula. Early Miocene (from 23–16mya): Proconsul was probably the last common ancestor of the hominoids. Proconsu

36 36 Middle Miocene Apes 16–10mya Ramapithecus (14mya) in Asia and Africa Drypopithecus (Europe) Sivapithecus (India) Kenyapithecus (East Africa) Direct ancestors?

37 37 Late Miocene Apes 10–5 mya The emergence of the hominids at the end of the Miocene and beginning of the Pliocene. Ouranopithecus and Oreopithecus (Europe) and possible bipedalism. Possible return migration to Africa from Europe during the late Miocene.

38 38 Differentiation of Primates in Africa Mid-Miocene, 16mya, the forests that dominate Africa recede and the savannas open. This favored the differentiation of primates into arboreal and terrestrial groups.

39 39 Theories for Differentiation Freeing hands (hunting, safety) Tall grass (seeing predators) Sharing food between males and females left females sedentary Using tools to capture food and as weapons allows hunting by otherwise puny animals Note use by contemporary chimps

40 40 Raymond Dart and the Taung Child Dart was a primate paleontologist Stone quarry near the Kalahari produced baboon fossils, 200 miles from Johannesburg Crates arrive in 1924 and Dart takes 73 days to isolate the Taung Child’s skull. 73 days to isolate

41 41 Dart’s reaction … “No diamond cutter ever worked more lovingly or with such care on a priceless jewel – nor, I am sure, with such inadequate tools. But on the 73rd day, Dec 23, the rock parted. I could view the face from the front, although the right side was still imbedded. The creature which had contained this massive brain was no giant anthropoid such as a gorilla. What emerged was a baby’s face, an infant with a full set of milk teeth and its permanent molars just in the process of erupting. I doubt if there was any parent prouder of his offspring than I was of my Taung baby on that Christmas.”

42 42 Australopithecus Dart names it Australopithecus africanus, suggesting that it was an intermediate species between apes and humans. Focus on the downward-facing foramen magnumdownward-facing foramen magnum

43 43 Robert Broom It takes until 1936 until another similar fossil is found. Two years later, in 1938, Broom discovers the Swartkrans site: 528 fossils of 60 individuals, over 14 years, plus 195 nonindigenous stones, some of which had been worked by human hands.

44 44 The Foramen Magnum Dart and Broom were rejected – the prevailing view was that the brain had evolved first. But there was that annoying fact of the downward facing foramen magnum The idea of the primacy of post- cranial evolution eventually won out.

45 45 Two Australopithecines? There were two kinds of Australopithecine, a gracile and a robust variety. The graciles were earlier, which caused confusion at first, since robust meant primitive to many observers.

46 46 Hominid sequence Isequence Sahelanthropus Ardipithecus ramidus Australopithecus anamensis Australopithecus afarensis Australopithecus africanus Taung Australopithecus robustus (P. robustus Australopithecus boisei (P. boisei, Zinj)

47 47 Hominid sequence IIsequence Homo habilis (P. rudolfensis) Homo rudolfensis Homo ergaster Homo erectus Trinil (P. erectus) Homo heidelbergensis Mauer Homo rhodesiensis Kabwe Homo neanderthalensis Homo sapiens

48 48 The Miocene Fossil Gap Closes Sahelanthropus tchadensis (Toumai) has a brain the size of a chimp’s, with a flat face. 6–7mya Sahelanthropus tchadensis

49 49 Ramidus 1994 Ethiopia – slightly forward foramen magnum. Perhaps still partially arboreal Anamensis 1965, not identified, 1994 Lake Turkana. Nearly full skeleton shows full bipedalism

50 50 A. afarensis Afarensis – Afar region of Ethiopia. Lucy at Hadar. Some 40 individuals. 3.7–2.9mya The afarensis footprints The afarensis footprints – 75 feet, Laetoli, Tanzania. Strong arch, well-defined ball, straight big toe. Brain case of 415cc (compare to chimp and gorilla and modern human) Canine diastema and protruding incisors. Dentition of Miocene apes, but orthograde

51 51 The transition to H. erectus A. robustus – late, from 1.88–1.62mya Some opposability in big toe Saggital and nuchal crests, like chimps Saggital and nuchal crests Probably mostly a vegetarian, but omnivorous A. bosei – even more robust – 2.3– 1.3mya. The last of the Australopithecines Enter H. ergaster 1.9mya

52 52 Homo ergaster Thought to be the earliest of the H. erectus line and the line that led to modern humans. 1.7mya cranial capacity 875cc Rounded cranium, large brow ridge, reduced teeth, thinner bones than Asian H. erectus. Acheulean hand axes and cleavers

53 53 H. erectus moves out of Africa to Asia and then to Europe before the advent of Acheulian tools. AsiaEurope H. ergaster may be a link between H. habilis and H. erectus or it may be a type of H. erectus.

54 54 Punctuated equilibrium Darwin thought that evolution proceeded through phyletic gradualism. Many fossil sequences have gaps Niles Eldridge and Stephen J. Gould thought that this might simply be the way evolution proceeded – with stability followed by rapid change.

55 55 R vs K strategy Stability confers no selective advantage on major evolutionary changes. Minor ones – speciation – continues. Note the case of cockroaches and sharks. This is the so-called r-strategy vs. K-strategy

56 56 Breeding isolates do occur and evolution is then quick if the isolate doesn’t quickly reestablish breeding contact with its former population. If this happens, there may not be enough time to produce a large fossil record, and this may be why there are so-called gaps.

57 57 Of course, both gradualism and PE can occur; in fact, PE is a form of gradualism Some mutations and changes from genetic drift may, in fact, feed to a whole population if the changes are highly advantageous. This may have occurred with sickle-cell trait in Africa.

58 58 But in PE, a geographic isolate can evolve quickly away from a former population and become a breeding isolate and a species unless breeding is reestablished quickly with the ancestral group. So, gaps in the fossil record may be true gaps, without any intermediate cases... or so few, over such as short time, that they may never be found.

59 59 If a new population is then very much more adapted to a changed (or even a stable) environment), it may replace the ancestral population if they are competitors for the same resources – and do so quickly.

60 60 This may have happened with H. erectus and also with H. sapiens sapiens replacing the Neanderthals.

61 61 Carbon-14 Carbon 14 Ratio of C-14 is constant during life At death, C-14 decays at a constant rate of 5730 years per half life. The method is good back to 80- 100,000 years

62 62 KA decomposition Much of the evidence for primate and hominid evolution is too old for C-14 KA is used when fossils are found between layers of volcanic ash. K decays to A in 1.31 billion years per half life. Gona River tools are the oldest so far, at 2.6mya, in the Afar region of Ethiopia. Gona River They are not in direct association with hominid fossils but have been found with cut- marked bone.

63 63 When did tool making start? A. robustus and H. habilis show a thumb metacarpal wider than that of the earliest hominids. thumb metacarpal This supports the development of tool making. But tool making must have been earlier.

64 64 When a chimp bangs a rock against a fruit, that is tool use. Tools are objects used to alter something else.

65 65 Chimp Culture Goodall and the Gombe chimps Goodall Chimps prepare a tool and carry it around, looking for termite moundstermite mounds Chimps also fish for ants in underground nestsfish for ants

66 66 Chimp Culture Chimps: 3 years to learn to fish for termites; 4 years to learn to fish for ants. Chimps make leaf sponges (Tanzania).leaf sponges collect hammer stones up to 33 pounds to open fruits (Ivory Coast).hammer stones hurl projectiles and gang up to capture baby bush pigs.

67 67 In captivity … The famous banana and box and stick experiment (1913-1917) Tulane Regional Primate Center escape.

68 68 Early Human Life Australopithecines must have made and used a variety of tools, long before afarensis. Chimps hunt and eat a lot of meat. Some Australopithecines were probably herbivores, but hunting is part of our hominid heritage.

69 69 Human sexuality and food sharing Earliest hominid females probably had estrus cycles. With the exception of the bonobo, primate sexuality is regulated by estrus – the readiness of the female to copulate at the peak of the ovulation cycle. Many available males mount chimp females during estrus.

70 70 Evolution of human sexuality In humans, the peak of the ovulation cycle is short, with no outward signs. Human females are sexually receptive throughout the year. This ensure that the egg is fertilized. What is the selective advantage?

71 71 Female sexual receptivity produces stronger male-female bonds of cooperation. Theory: frequent satisfying of mutual sexual needs may account for the unique bonding among primates of male and female humans.

72 72 Bonobo sexuality and food sharingsexuality Support for this theory: the mating behavior of bonobo chimpanzees. Female remains receptive all year. Males and females copulate daily and, more than other chimps, they tend to share food with one another, with females initiating food sharing by copulating with males that have some food.

73 73 Early human culture H. ergaster, in East Africa, is the first H. erectus, about 1.9mya Acheulean hand axes are a major advance in lithic technology, along with the increase in brain size. Compare to Oldowan pebble tools Acheulean hand Compare to Oldowan pebble tools

74 74 The culture of H. erectus Hunting becomes more important in the next stage Australopithecines were omnivorous. Coprolites with evidence for meat eating at the Plio-Pleistocene boundary – but this was probably scavenging H. habilis and H. erectus hunted meat The shift from H. habilis to H. erectus in Africa and the Achulean hand axe traditionhand axe

75 75 The Asian H. erectus finds Solo Man in Java first dated at.9mya Peking man in China.85mya Over 1000cc brain case in Zhoukoudian No Acheulean tools with Asian H. erectus With such big brains, why not? Early migration and the Bamboo theory. Java finds and Chinese finds now dated at 1.9 mya.

76 76 Java Man First erectus discovered by Eugene Dubois, a Dutch physician, at Trinil in Java, 1891 – named Paranthropus erectus. Note the supraorbital ridges and remnants of saggital crest in the Trinil skull. 1.0-.7mya, but Ngangdong skulls, also in Java, are at just 27-53kya, along with H. sapiens sapiens.

77 77 Peking Man Zhoukoudian, China 1930 –named Sinanthropus pekinensis, or Peking Man. Zhoukoudian, China.5–.23mya 1950, Ernst Mayr collapsed Sinanthropus and Paranthropus into H. erectusErnst Mayr

78 78 No Acheulean Tools in Asian H. erectus: Dmanisi Asian H. erectus With new dating tools, Java finds are back to 1.9mya, the time of H. ergaster. Dmanisi, in the Georgian Republic, 1.5–1.8myain the Georgian Republic H. erectus in Europe,.8–.3mya, with Acheulean tools at.5mya Hence the bamboo theory

79 79 The Fialkowski Hypothesis Lots of evidence for H. erectus the hunter Olorgesailie, Kenya; Terra Amata, France; Torralba and Ambrona, Spain – piles of bones from single species. Were they scavanged and collected? H. erectus brain size is 800–1000cc, which stradles H. habilis and H. sapiens

80 80 Better tools, more social behavior and sharing of resources – highly adaptive for getting through tough times Brain size remained stable from 1.9–.5mya Konrad Fialkowski explains this with the hunting hypothesis and protection from the sun during the day. This is not testable, however.

81 81 H. habilis and early H. erectus did not produce projectile points. This would not have been necessary for hunting with the methods used by recent !Kung hunters. So, larger brain size may have led eventually to increments in language and culture capacity, but that was not required for the large brain size of H. erectus.

82 82 Questions About H. sapiens 1. When was the transition? 2. Where was the transition? 3. Who were the Neandertals? H. erectus evolved into H. sapiens between.5mya and.2mya. The current best estimate is that the transition took place between 400,000 years ago and 200,000 years ago but had been started perhaps 800,000 to 500,000 years ago.

83 83 Transition to H. sapiens Occurs in several parts of the world. Petralona skull, Greece,.4mya; Arago- Tautavel skull from southern France.3mya; Kabwe, Zambia, between.3–.124mya 1300cc The Mauer specimen, from Germany 1300cc. The Mauer date is relative to faunal remains around it. The Mauer specimen, from Germany May be.5mya. Kabwe at least.125mya, but), but perhaps.3mya. Kabwe remains are continually re-evaluated as least.125mya

84 84 No occipital torus Mauer and Kabwe skull lack saggital crest or occipital torus, but do have large supraorbital ridges and strong prognathism, with a sloping forehead and large mandible. These are type fossils, but are found in Africa and Europe and Solo, in Indonesia.

85 85 Anatomically Modern Humans Fully modern humans 35,000 years old in Europe and 130,000 years in Africa, at the Klasies River caves and Border Cave in South Africa and Omo in Ethiopia.River caves Border Cave Skhul and Qafzeh (modern Israel), H. sapiens at 92,000 years.and Qafzeh 40,000 years in Borneo and 30,000 years in Australia 40,000 years in Borneo and 30,000 years in Australia Earliest modern humans in the Americas at 15,000 Earliest modern humans in the Americas

86 86 H. Sapiens sapiens Higher, bulging foreheads; lighter bones; smaller faces and jaws; the chin (the remnant of prognathism) and small or no supraorbital ridges In Qafzeh, as well as at Skhul, remains of H. sapiens beginning at 92,000 years ago. Nearby sites have Neandertals at 60,000 years ago. They coexisted for at least 30,000 years in the Near East.

87 87 Who Were the NeandertalsWho Were the Neandertals? Europe through western Asia (Israel, Syria, Iraq, Uzbekistan) from about 200,000 to about 30,000 years ago. 1856, Neander Valley near Dusseldorf, Germany. 1856, Neander Valley near Dusseldorf, Germany. A disfigured H. sapiens? More Neandertal finds across Europe.

88 88 Mitochondrial DNA 1950s, we found that the specimen had suffered from rickets By then, we had the Australopithecines and H. erectus finds – and Neandertal looked like us 1997, mtDNA extracted from the 1856 Neandertal. Mutation rate tells us (if the measurements are correct) that it has been 600,000 years since Neandertal and AMH shared a common ancestor. 1997, mtDNA extracted from the 1856 Neandertal

89 89 Single and Multiple Origin This supports the out of Africa, single- origin theory of the development of modern H. sapiens. Single origin: mtDNA. 1987, comparison of mtDNA from U.S., New Guinea, Africa, and East Asia. Cann et al. conclude: people shared a common ancestor 200,000 years ago from East Africa.

90 90 mtDNA and the co-existence of H. sapiens and Neandertals in the Mt. Carmel for 30,000 years supports the out-of-Africa theory. The MR theory: H. erectus populations evolved into varieties of H. sapiens in place, across the globe. Note continuities between modern populations and H. erectus populations in Southeast Asia and China

91 91 Muliregionalism vs. Out of Africa Unbroken brow ridges, large molars and cheek bones, some prognathism, Multiregionalists argue that the mtDNA evidence supports the out-of-Africa migration of H. erectus, not H. sapiensargue that the mtDNA But this means that the mutation rate of mtDNA would have to be slower than 2% per million years. The 2% figure is supported by some data, but not all.

92 92 Where Did the Neandertals Go? Three theories: absorption, extinction, and slaughter Interbreeding is possible, but genocide is unlikely The Neandertals appear in pockets – regions of refuge – in Spain and go extinct around 30,000 years ago.

93 93 H. Sapiens and adaptive radiationadaptive radiation 5 million years to first billion (1800) 125 years to two billion (1925) 34 years to three billion (1959) 15 years to four billion (1974) 12 years to five 5 billion 12 (1986) 15 years to 6 billion (2001) 6.5 billion in 2006. 6.5 billion in 2006

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