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Biological Anthropology

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Title: Biological Anthropology


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

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

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 Lyells work by challenging
    the accepted age of the Earth.

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.

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
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
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
  • 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
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.

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

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 (18231913) was in
    Malaysia, writing papers offering the same theory
    of evolution that Darwin was developing.
  • Darwin published first.

17
Darwins 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
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 Lamarcks theory.
  • The traits of all offspring conformed to those of
    the parent generation.
  • And of course, there were Mendels peas.

19
The First Primates
  • The Earth is about 4.5 billion 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.

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
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
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 Huxleys book, Mans Place in
    Nature contained a conclusion about the close
    relationship between African apes and modern
    humans.

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
Prosimians
  • Two suborders Prosimians and Anthropoids
  • Prosimians include the lorises, tarsiers and
    lemurs of Asia and Africa.
  • The special case of Madagascar. See Kottaks
    discussion of this.
  • 65 mya

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.
  • Two types catarrhines (Old World monkeys and
    apes) and platyrrhines (New World monkeys)
    separated 35mya in the Oligocene.

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.
  • There is only one species of hominid today, H.
    sapiens sapiens.

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

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
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
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
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
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
  • 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
  • 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
Fossil Primates
  • Oligocene anthropoids Aegyptopithecus (33mya)
    had the
  • 2-1-2-3 dental formula.
  • Early Miocene (from 2316mya) Proconsul was
    probably the last common ancestor of the
    hominoids.

36
Middle Miocene Apes
  • 1610mya
  • Ramapithecus (14mya) in Asia and Africa
  • Drypopithecus (Europe)
  • Sivapithecus (India)
  • Kenyapithecus (East Africa)
  • Direct ancestors?

37
Late Miocene Apes 105 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
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
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
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 Childs skull.

41
Darts 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 babys 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
Australopithecus
  • Dart names it Australopithecus africanus,
    suggesting that it was an intermediate species
    between apes and humans.
  • Focus on the downward-facing foramen magnum

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

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

48
The Miocene Fossil Gap Closes
  • Sahelanthropus tchadensis (Toumai) has a brain
    the size of a chimps, with a flat face. 67mya

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
A. afarensis
  • Afarensis Afar region of Ethiopia. Lucy at
    Hadar. Some 40 individuals. 3.72.9mya
  • 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
The transition to H. erectus
  • A. robustus late, from 1.881.62mya
  • Some opposability in big toe
  • Saggital and nuchal crests, like chimps
  • Probably mostly a vegetarian, but omnivorous
  • A. bosei even more robust 2.31.3mya. The
    last of the Australopithecines
  • Enter H. ergaster 1.9mya

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

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
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
  • Breeding isolates do occur and evolution is then
    quick if the isolate doesnt 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
  • 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
  • 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
  • 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
  • This may have happened with H. erectus and also
    with H. sapiens sapiens replacing the
    Neanderthals.

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
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.
  • They are not in direct association with hominid
    fossils but have been found with cut-marked bone.

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

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

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

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).
  • collect hammer stones up to 33 pounds to open
    fruits (Ivory Coast).
  • hurl projectiles and gang up to capture baby bush
    pigs.

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

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
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
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
  • 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
Bonobo sexuality and food sharing
  • 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
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

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 tradition

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
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
Peking Man
  • Zhoukoudian, China 1930 named Sinanthropus
    pekinensis, or Peking Man.
  • .5.23mya
  • 1950, Ernst Mayr collapsed Sinanthropus and
    Paranthropus into H. erectus

78
No Acheulean Tools in Asian H. erectus Dmanisi
  • With new dating tools, Java finds are back to
    1.9mya, the time of H. ergaster.
  • Dmanisi, in the Georgian Republic, 1.51.8mya
  • H. erectus in Europe, .8.3mya, with Acheulean
    tools at .5mya
  • Hence the bamboo theory

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 8001000cc, which
    stradles H. habilis and H. sapiens

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
  • 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
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
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.
  • May be .5mya. Kabwe at least .125mya, but), but
    perhaps .3mya. Kabwe remains are continually
    re-evaluated as older.

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
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.
  • Skhul and Qafzeh (modern Israel), H. sapiens at
    92,000 years.
  • 40,000 years in Borneo and 30,000 years in
    Australia
  • Earliest modern humans in the Americas at 15,000

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
Who 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.
  • A disfigured H. sapiens? More Neandertal finds
    across Europe.

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.

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
  • 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
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. sapiens
  • 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
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
H. Sapiens and adaptive 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.
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