Primate and Human Evolution - PowerPoint PPT Presentation

About This Presentation
Title:

Primate and Human Evolution

Description:

from gorillas about 8 million years ago. and humans separated from chimpanzees ... In gorillas the ischium bone is long. and the entire pelvis is tilted toward ... – PowerPoint PPT presentation

Number of Views:749
Avg rating:3.0/5.0
Slides: 126
Provided by: ThomsonBr1
Learn more at: http://www.geol.lsu.edu
Category:

less

Transcript and Presenter's Notes

Title: Primate and Human Evolution


1
Chapter 19
Primate and Human Evolution
2
Oldest Hominid
  • Sahelan-thropus tchadensis,
  • the oldest known hominid,
  • nearly 7 million years old,
  • was discovered in 2002 in Chad

3
Who are we?
  • Who are we?
  • Where did we come from?
  • What is the human genealogy?
  • These are basic questions
  • that probably everyone at some time or another
  • has asked themselves

4
Goes Back Farther Than We Thought
  • Many people enjoy tracing
  • their own family history as far back as they can,
  • similarly paleoanthropologists are discovering,
  • based on recent fossil finds
  • that the human family tree goes back
  • much farther than we thought

5
Hope of Life
  • In fact, a skull found in the African nation of
    Chad,
  • in 2002 and named Sahelanthropus tchadensis
  • but nicknamed Tourmaï,
  • which means "hope of life"
  • in the local Goran language,
  • has pushed back the origins of humans
  • to nearly 7 million years ago
  • Instead of simplifying our ancestry, however,
  • its discovery has raised more questions
  • than it answered

6
Bushy Model of Human Evolution
  • For instance, paleoanthropologists now think
  • that human evolution branched many times
  • rather than evolving in a somewhat straight line
  • leading to modern humans
  • According to this bushy model
  • of human evolution,
  • such key traits as
  • upright walking,
  • manual dexterity
  • and a large brain
  • evolved more than once,
  • and produced many evolutionary dead-ends

7
When Humans and Chimpanzees Diverged
  • Presently, most paleoanthropologists accept
  • that the human-chimpanzee stock separated
  • from gorillas about 8 million years ago
  • and humans separated from chimpanzees
  • about 5 million years ago
  • Thus Sahelanthropus tchadensis is
  • at or near the point in time
  • when humans and chimpanzees diverged

8
Oldest Hominid
  • Besides being the oldest hominid,
  • humans and their extinct ancestors,
  • Sahelanthropus tchadensis shows a mosaic
  • of primitive and advanced features
  • that has excited and puzzled paleoanthropologists
  • The small brain case and most of the teeth
  • (except the canines) are chimplike
  • However, the nose, which is fairly flat,
  • and the prominent brow ridges
  • are features only seen, until now,
  • in the human genus Homo

9
Understanding in Flux
  • So where does this leave us, evolutionarily
    speaking?
  • At a very exciting time as we seek to unravel the
    history of our species
  • Our understanding of our genealogy
  • is presently in flux,
  • and each new fossil hominid find
  • sheds more light on our ancestry

10
Human Evolution
  • Apparently human evolution
  • is just like that of other groups
  • Just as with nonhominid predecessors,
  • our ancestors followed an uncertain path
  • As new species evolved,
  • they filled ecologic niches
  • and either gave rise to descendants
  • better adapted to the changing environment
  • or became extinct

11
New Hypotheses About Our Ancestry
  • In this section we examine the various primate
    groups,
  • in particular the origin and evolution of the
    hominids,
  • the group that includes our ancestors
  • However, we must point out
  • that new discoveries of fossil hominids,
  • as well as new techniques for scientific analysis
  • are leading to new hypotheses about our ancestry

12
Continuing Discoveries Change Our Ideas
  • As recently as 2000,
  • the earliest fossil evidence of hominids
  • was from 4.4-million-year-old rocks in eastern
    Africa
  • Since then, as just noted, discoveries have
    pushed
  • that age back to almost 7 million years

13
Exciting Study
  • Even as we speak, therefore,
  • new discoveries may have changed
  • some of our conclusions
  • based on what we currently know
  • Such is the nature of paleoanthropology
  • and one reason why the study of hominids
  • is so exciting

14
What Are Primates?
  • Primates are difficult to characterize as an
    order
  • because they lack the strong specializations
  • found in most other mammalian orders
  • We can, however, point to several trends
  • in their evolution that help define primates
  • and are related to their arboreal,
  • or tree-dwelling, ancestry

15
Trends in Primates
  • These include changes in the skeleton
  • and mode of locomotion,
  • an increase in brain size,
  • a shift toward smaller, fewer,
  • and less specialized teeth,
  • and the evolution of stereoscopic vision
  • and a grasping hand with opposable thumb
  • Not all these trends took place in every primate
    group,
  • nor did they evolve at the same rate in each group

16
Variations
  • In fact, some primates
  • have retained certain primitive features,
  • whereas others show all
  • or most of these trends

17
Classification of Primates
  • The primate order is divided into two suborders
  • The prosimians, or lower primates,
  • include the lemurs, lorises, tarsiers, and tree
    shrews,
  • while the anthropoids, or higher primates,
  • include monkeys, apes, and humans

18
Classification of Primates
  • Order Primates
  • Suborder Prosimii (lower primates) Lemurs,
    lorises, tarsiers, tree shrews
  • Suborder Anthropoidea (Higher primates) Monkeys,
    apes, humans
  • Superfamily Cercopithecoidea Macaque, baboon,
    proboscis monkey
  • Superfamily Ceboidea Howler, spider, and
    squirrel monkeys
  • Superfamily Hominoidea Apes, humans
  • Family Pongidae Chimpanzees, orangutans,
    gorillas
  • Family Hylobatidae Gibbons, siamangs
  • Family Hominidae Humans

19
Prosimians
  • Prosimians are generally small,
  • ranging from species the size of a mouse
  • up to those as large as a house cat
  • They are arboreal, have five digits
  • on each hand and foot
  • with either claws or nails,
  • and are typically omnivorous
  • They have large, forwardly directed eyes
  • specialized for night vision,
  • hence most are nocturnal

20
Tarsier
  • Tarsiers are prosimian primates

21
Ring-Tailed Lemur
  • Ring-Tailed Lemur are also prosimians

22
Prosimians
  • As their name implies
  • pro means "before," and simian means "ape,
  • prosimians are the oldest primate lineage,
  • and their fossil record extends back to the
    Paleocene
  • During the Eocene prosimians were
  • abundant, diversified, and widespread
  • in North America, Europe, and Asia

23
Eocene Prosimian
  • Notharctus, a primitive Eocene prosimian
  • from North America

24
Prosimians Declined in Cooler Climate
  • As the continents moved northward
  • during the Cenozoic
  • and the climate changed from warm tropical
  • to cooler midlatitude conditions,
  • the prosimian population decreased
  • in both abundance and diversity

25
Prosimians Are Tropical
  • By the Oligocene, hardly any prosimians
  • were left in the northern continents
  • as the once widespread Eocene populations
  • migrated south to the warmer latitudes
  • of Africa, Asia, and Southeast Asia
  • Presently, prosimians are found
  • only in the tropical regions
  • of Asia, India, Africa, and Madagascar

26
Anthropoids
  • Anthropoids evolved from a prosimian lineage
  • sometime during the Late Eocene,
  • and by the Oligocene
  • they were well established
  • Anthropoids are divided into three superfamilies

27
New World Monkey
  • New World Monkeys constitute a superfamily
    belonging to the suborder Anthropoidea
    (anthropoids)

28
Old Word Monkey
  • Another superfamily of the anthropoids
  • the Old World monkeys

29
Great Apes
  • The third superfamily is the great apes,
  • which include Gorillas and...

30
Chimpanzee
  • Chimpanzees

31
Early History of Anthropoids
  • Much of our knowledge about
  • the early evolutionary history of anthropoids
  • comes from fossils found in the Fayum district,
  • a small desert area southwest of Cairo, Egypt
  • During the Late Eocene and Oligocene,
  • this region of Africa was a lush, tropical rain
    forest
  • that supported a diverse and abundant fauna and
    flora
  • Within this forest lived many different
  • arboreal anthropoids as well as various prosimians

32
Thousands of Fossil Specimens
  • In fact, several thousand fossil specimens
  • representing more than 20 species of primates
  • have been recovered from rocks of this region
  • One of the earliest anthropoids,
  • and a possible ancestor of the Old World monkeys,
  • was Aegyptopithecus,
  • a small, fruit-eating, arboreal primate
  • that weighed about 5 kg

33
One of the Earliest Anthropoids
  • Skull of Aegyptopithecus zeuxis,
  • one of the earliest known anthropoids

34
Anthropoid Superfamilies
  • Anthropoids are divided into three superfamilies
  • Old World monkeys,
  • New World monkeys,
  • and hominoids

35
Classification of Primates
  • Order Primates
  • Suborder Prosimii (lower primates) Lemurs,
    lorises, tarsiers, tree shrews
  • Suborder Anthropoidea (Higher primates Monkeys,
    apes, humans
  • Superfamily Cercopithecoidea Macaque, baboon,
    proboscis monkey
  • Superfamily Ceboidea Howler, spider, and
    squirrel monkeys
  • Superfamily Hominoidea Apes, humans
  • Family Pongidae Chimpanzees, orangutans,
    gorillas
  • Family Hylobatidae Gibbons, siamangs
  • Family Hominidae Humans

36
Old World Monkey Attributes
  • Old World monkeys
  • superfamily Cercopithecoidea
  • are characterized by close-set,
  • downward-directed nostrils
  • like those of apes and humans
  • grasping hands,
  • and a nonprehensile tail
  • They include
  • the macaque,
  • baboon,
  • and proboscis monkey

37
Old Word Monkey
  • Superfamily Cercopithecoidea
  • the Old World monkeys

38
Old World Monkeys Distribution
  • Present-day Old World monkeys
  • are distributed in the tropical regions
  • of Africa and Asia
  • and are thought to have evolved
  • from a primitive anthropoid ancestor,
  • such as Aegyptopithecus,
  • sometime during the Oligocene

39
New World Monkeys
  • New World monkeys
  • superfamily Ceboidea
  • are found only in Central and South America
  • They probably evolved from African monkeys
  • that migrated across the widening Atlantic
  • sometime during the Early Oligocene,
  • and they have continued evolving in isolation
  • to this present day

40
New World Monkey
  • New World Monkeys are members of the superfamily
    Ceboidea

41
No Contact
  • No evidence exists of any prosimian
  • or other primitive primates
  • in Central or South America
  • nor of any contact with Old World monkeys
  • after the initial immigration from Africa
  • New World monkeys are characterized
  • by a prehensile tail, flattish face,
  • and widely separated nostrils
  • and include the howler, spider, and squirrel
    monkeys

42
Hominoids
  • Hominoids
  • superfamily Hominoidea
  • consist of three families
  • the great apes
  • family Pongidae
  • which includes chimpanzees, orangutans, and
    gorillas
  • the lesser apes
  • family Hylobatidae
  • which are gibbons and siamangs
  • and the hominids
  • family Hominidae
  • which are humans and their extinct ancestors

43
Hominoid Lineage
  • The hominoid lineage
  • diverged from Old World monkeys
  • sometime before the Miocene,
  • but exactly when is still being debated
  • It is generally accepted, however,
  • that hominoids evolved in Africa,
  • probably from the ancestral group
  • that included Aegyptopithecus

44
Climatic Shifts
  • Recall that beginning in the Late Eocene
  • the northward movement of the continents
  • resulted in pronounced climatic shifts
  • In Africa, Europe, Asia, and elsewhere,
  • a major cooling trend began,
  • and the tropical and subtropical rain forests
  • slowly began to change to a variety of mixed
    forests
  • separated by savannas and open grasslands
  • as temperatures and rainfall decreased

45
Apes Adapted
  • As the climate changed,
  • the primate populations also changed
  • Prosimians and monkeys became rare,
  • whereas hominoids diversified
  • in the newly forming environments
  • and became abundant
  • Ape populations became reproductively isolated
  • from each other within the various forests,
  • leading to adaptive radiation
  • and increased diversity among the hominoids

46
Migration of Animals Possible
  • During the Miocene,
  • Africa collided with Eurasia,
  • producing additional changes in the climate,
  • as well as providing opportunities
  • for migration of animals
  • between the two landmasses

47
Hominoid Relationships
  • Two apelike groups evolved during the Miocene
  • that ultimately gave rise to present-day
    hominoids
  • Although scientists still disagree
  • on the early evolutionary relationships among the
    hominoids,
  • fossil evidence and molecular DNA similarities
  • between modern hominoid families
  • is providing a clearer picture of the
    evolutionary pathways
  • and relationships among the hominoids

48
Dryopithecines
  • The first group, the dryopithecines,
  • evolved in Africa during the Miocene
  • and subsequently spread to Eurasia,
  • following the collision between the two
    continents
  • The dryopithecines were a varied group of
    hominoids
  • in size,
  • skeletal features,
  • and life-style

49
Proconsul
  • The best-known dryopithecine and perhaps
  • ancestor of all later hominoids
  • is Proconsul,
  • an ape-like fruit-eating animal
  • that led a quadrupedal arboreal existence,
  • with limited activity on the ground
  • The dryopithecines were very abundant
  • and diverse during the Miocene and Pliocene,
  • particularly in Africa

50
Proconsul
  • Probable appearance of Proconsul, a dryopithecine

51
Sivapithecids
  • The second group, the sivapithecids,
  • evolved in Africa during the Miocene
  • and then spread throughout Eurasia
  • The fossil remains of sivapithecids
  • consist mostly of jaws, skulls, and isolated
    teeth
  • There are few body or limb bones known,
  • and thus we know little about their body anatomy

52
Sivapithecids Ate Harder Foods
  • All sivapithecids had powerful jaws and teeth
  • with thick enamel and flat chewing surfaces,
  • suggesting a diet of harder foods such as nuts
  • Based on various lines of evidence,
  • the sivapithecids appear to be the ancestral
    stock
  • from which present-day orangutans evolved

53
Two Lineages
  • Although many pieces are still missing,
  • particularly during critical intervals
  • in the African hominoid fossil record,
  • molecular DNA as well as fossil evidence
    indicates
  • that the dryopithecines, African apes, and
    hominids
  • form a closely related lineage
  • The sivapithecids and orangutans
  • form a different lineage that did not lead to
    humans

54
Hominids
  • The hominids (family Hominidae)
  • the primate family that includes present-day
    humans
  • and their extinct ancestors
  • have a fossil record extending back
  • to almost 7 million years
  • Several features distinguish them from other
    hominoids
  • Hominids are bipedal
  • that is, they have an upright posture,
  • which is indicated by several modifications in
    their skeleton

55
Comparison of Locomotion
  • Comparison between quadrupedal and bipedal
    locomotion
  • in gorillas and humans
  • In gorillas the ischium bone is long
  • and the entire pelvis is tilted toward the
    horizontal

56
Comparison of Locomotion
  • Comparison between quadrupedal and bipedal
    locomotion
  • in gorillas and humans
  • In humans the ischium bone is much shorter
  • and the pelvis is vertical

57
Larger Reorganized Brain
  • In addition, hominids show a trend
  • toward a large and internally reorganized brain
  • An increase in brain size and organization
  • is apparent in comparing the brains of
  • a New World Monkey

58
Larger Reorganized Brain
  • In addition, hominids show a trend
  • toward a large and internally reorganized brain
  • An increase in brain size and organization
  • is apparent in comparing the brains of
  • a great ape

59
Larger Reorganized Brain
  • In addition, hominids show a trend
  • toward a large and internally reorganized brain
  • An increase in brain size and organization
  • is apparent in comparing the brains of
  • a present-day human

60
Other Distinguishing Features
  • Other features that distinguish hominids from
    other hominoids include
  • a reduced face
  • and reduced canine teeth,
  • omnivorous feeding,
  • increased manual dexterity,
  • and the use of sophisticated tools

61
Response to Climatic Changes
  • Many anthropologists think
  • these hominid features evolved in response
  • to major climatic changes
  • that began during the Miocene
  • and continued into the Pliocene
  • During this time, vast savannas
  • replaced the African tropical rain forests
  • where the lower primates
  • and Old World monkeys had been so abundant

62
Mixed Forests and Grasslands
  • As the savannas and grasslands
  • continued to expand,
  • the hominids made the transition
  • from true forest dwelling
  • to life to an environment
  • of mixed forests and grasslands

63
No Clear Consensus
  • At present, no clear consensus exists
  • on the evolutionary history of the hominid
    lineage
  • This is due in part
  • to the incomplete fossil record of hominids
  • as well as new discoveries,
  • and also because some species
  • are known only from partial specimens
  • or fragments of bone
  • Because of this, scientists even disagree
  • on the total number of hominid species

64
Some Current Theories
  • A complete discussion
  • of all the proposed hominid species
  • and the various competing schemes of hominid
    evolution
  • is beyond the scope of this course
  • However, we will discuss the generally accepted
    taxa
  • and present some of the current theories
  • of hominid evolution

65
Geologic Age Ranges
  • The geologic age ranges
  • for the commonly accepted species of hominids

66
Debates
  • Remember that although the fossil record
  • of hominid evolution is not complete,
  • what does exist is well documented
  • Furthermore, it is the interpretation of that
    fossil record
  • that precipitates the often vigorous
  • and sometimes acrimonious debates
  • concerning our evolutionary history

67
Oldest Known Hominid
  • Discovered in northern Chad's Djurab Desert
  • in July, 2002,
  • the nearly 7-million-year-old skull
  • and dental remains of Sahelanthropus tchadensis
  • make it the oldest known hominid yet unearthed
  • and very close to the time
  • when humans diverged
  • from our closest-living relative, the chimpanzee

68
Leg Bones and Feet Needed
  • Sahelanthropus tchadensis may have been
  • bipedal in its walking habits,
  • but until bones from its legs and feet are found,
  • that supposition remains conjecture

69
Next Oldest Hominid
  • The next oldest hominid is Orrorin tugenensis,
  • whose fossils have been dated at six million
    years
  • and consist of bits of jaw, isolated teeth,
  • finger, arm, and partial upper leg bones
  • At this time, debate continues
  • as to exactly where Orrorin tugenensis fits in
    the hominid lineage

70
Ardipithecus ramidus
  • Sometime between 5.8 and 5.2 million years ago,
  • another hominid was present in eastern Africa
  • Ardipithecus ramidus kadabba is older
  • than its 4.4 million year old relative
  • Ardipithecus ramidus ramidus
  • Ardipithecus ramidus kadabba is very similar
  • in most features to Ardipithecus ramidus ramidus
  • but in certain features of its teeth
  • is more apelike than its younger relative

71
Geologic Age Ranges
  • The geologic age ranges
  • for the commonly accepted species of hominids

72
Habitual Bipedal Walkers
  • Although many paleoanthropologists think
  • both Orrorin tugenensis and Ardipithecus ramidus
    kadabba
  • were habitual bipedal walkers
  • and thus on a direct evolutionary line to humans,
  • others are not as impressed with the fossil
    evidence
  • and are reserving judgment
  • Until more fossil evidence is found and analyzed,
  • any single scheme of hominid evolution presented
    here would be premature

73
Australopithecines
  • Australopithecine is a collective term
  • for all members of the genus Australopithecus
  • Currently, five species are recognized
  • A. anamensis,
  • A. afarensis,
  • A. africanus,
  • A. robustus,
  • and A. boisei

74
Evolutionary Scheme
  • Many paleontologists accept
  • the evolutionary scheme in which
  • A. anamensis,
  • the oldest known australopithecine,
  • is ancestral to A. afarensis,
  • who in turn is ancestral to A. africanus
  • and the genus Homo,
  • as well as the side branch of australopithecines
  • represented by A. robustus and A. boisei

75
Oldest Known Australopithecine
  • The oldest known australopithecine
  • is Australopithecus anamensis
  • and was discovered at Kanapoi,
  • a site near Lake Turkana, Kenya,
  • by Meave Leakey
  • of the National Museums of Kenya
  • and her colleagues

76
Similar Yet More Primitive
  • A. anamensis, a 4.2-million-year-old bipedal
    species,
  • has many features in common
  • with its younger relative, A. afarensis,
  • yet is more primitive in other characteristics,
  • such as its teeth and skull
  • A. anamensis
  • is estimated to have been
  • between 1.3 and 1.5 m tall
  • and weighed between 33 and 50 kg

77
Australopithecus afarensis
  • Australopithecus afarensis,
  • which lived 3.93.0 million years ago,
  • was fully bipedal
  • and exhibited great variability in size and
    weight
  • Members of this species ranged
  • from just over 1 m to about 1.5 m tall
  • and weighed between 29 and 45 kg

78
Lucy
  • A reconstruction of Lucys skeleton
  • by Owen Lovejoy
  • and his students at Kent State University, Ohio
  • Lucy is an 3.5-million-year-old
  • Australopithecus afarensis individual
  • whose fossil remains were discovered by Donald
    Johanson
  • This recon-struction
  • illustrates how adaptations in
  • Lucys hip, leg and foot
  • allowed a fully bipedal
  • means of locomotion

79
Hominid Footprints
  • Preserved in volcanic ash at Laetoli, Tanzania
  • Discovered in 1978 by Mary Leakey,
  • these footprints proved hominids
  • were bipedal walkers at least 3.5 million years
    ago
  • The footprints of two adults and possibly those
    of a child
  • are clearly visible in this photograph

80
Hominid Footprints
  • Most scientists think the footprints
  • were made by Australopithecus afarensis
  • whose fossils are found at Laetoli

81
Brain Size of A. afarensis
  • A. afarensis had a brain size of 380450 cubic
    centimeters (cc),
  • larger than the 300400 cc
  • of a chimpanzee
  • but much smaller than that of present-day humans
    (1350 cc average)

82
Apelike Features
  • The skull of A. afarensis retained many apelike
    features,
  • including massive brow ridges
  • and a forward-jutting jaw,
  • but its teeth were intermediate
  • between those of apes and humans
  • The heavily enameled molars
  • were probably an adaptation to chewing fruits,
    seeds, and roots

83
Landscape with A. afarensis
  • Re-creation of a Pliocene landscape
  • showing members of
  • Australo-pithecus afarensis
  • gathering and eating
  • various fruits and seeds

84
A. africanus Lived 3.02.3 mya
  • A. afarensis was succeeded by
  • Australopithecus africanus,
  • which lived 3.02.3 million years ago
  • The differences between the two species are
    relatively minor
  • They were both about the same size and weight,
  • but A. africanus had a flatter face
  • and somewhat larger brain

85
Skull of A. africanus
  • A reconstruction of the skull
  • of Australopithecus africanus
  • This skull,
  • known as that of the Taung Child,
  • was discovered by Raymond Dart in South Africa in
    1924
  • and marks the beginning of modern
    paleoanthropology

86
Not As Well Adapted for Bipedalism
  • It appears the limbs
  • of A. africanus may not have been
  • as well adapted for bipedalism
  • as those of A. afarensis

87
Robust Species
  • Both A. afarensis and A. africanus
  • differ markedly from the so-called robust species
  • A. boisei (2.61.0 million years ago)
  • and A. robustus (2.01.2 million years ago)
  • A. boisei was 1.21.4 m tall
  • and weighed between 34 and 49 kg
  • It had a powerful upper body,
  • a distinctive bony crest on the top of its skull,
  • a flat face, and the largest molars of any
    hominids

88
A. robustus Was a Vegetarian
  • A. robustus, in contrast,
  • was somewhat smaller (1.11.3 m tall)
  • and lighter (3240 kg)
  • It had a flat face, and the crown of its skull
  • had an elevated bony crest
  • that provided additional area
  • for the attachment of strong jaw muscles
  • Its broad flat molars indicated
  • A. robustus was a vegetarian

89
Australopithecus robustus Skull
  • The skull of Australopithecus robustus
  • This species had a massive jaw,
  • powerful chewing muscles,
  • and large broad flat chewing teeth
  • apparently used for grinding up coarse plant food

90
Separate Lineage
  • Most scientists accept the idea
  • that the robust australopithecines
  • form a separate lineage
  • from the other australopithecine
  • that went extinct 1 million years ago

91
The Human Lineage
  • Homo habilis
  • The earliest member of our own genus Homo
  • is Homo habilis,
  • which lived 2.5-1.6 million years ago
  • Its remains were first found at Olduvai Gorge,
  • but it is also known
  • from Kenya, Ethiopia, and South Africa
  • H. habilis evolved from the A. afarensis and A.
    africanus lineage
  • and coexisted with A. africanus
  • for about 200,000 years

92
Geologic Age Ranges
  • The geologic age ranges
  • for the commonly accepted species of hominids

93
Characteristics of Homo habilis
  • H. habilis had a larger brain (700 cc average)
  • than its australopithecine ancestors,
  • but smaller teeth
  • It was about 1.2-1.3 m tall
  • and only weighed 32-37 kg

94
Homo Erectus
  • In contrast to the australopithecines and H.
    habilis,
  • which are unknown outside Africa,
  • Homo erectus was a widely distributed species,
  • having migrated from Africa during the
    Pleistocene
  • Specimens have been found
  • not only in Africa
  • but also in Europe, India, China ("Peking Man"),
  • and Indonesia ("Java Man")

95
Survived in Asia Until About 100,000 Years Ago
  • H. erectus evolved in Africa 1.8 million years
    ago
  • and by 1 million years ago
  • was present in southeastern and eastern Asia,
  • where it survived until about 100,000 years ago

96
H. erectus Differed From Modern Humans
  • Although H. erectus developed regional variations
    in form,
  • the species differed from modern humans in
    several ways
  • Its brain size of 800-1300 cc,
  • though much larger than that of H. habilis,
  • was still less than the average for Homo sapiens
    (1350 cc)

97
Size Similar to Humans
  • H. erectus's skull was thick-walled,
  • its face was massive,
  • it had prominent brow ridges,
  • and its teeth were slightly larger than those of
    present-day humans
  • H. erectus was comparable to size to modem
    humans,
  • standing between 1.6 and 1.8 m tall
  • and weighing between 53 and 63 kg

98
Skull of Homo erectus
  • A reconstruction of the skull of Homo erectus
  • a widely distributed species
  • whose remains have been found
  • in Africa, Europe, India, China, and Indonesia

99
H. erectus Was a Tool Maker
  • The archaeological record indicates
  • that H. erectus was a tool maker
  • Furthermore, some sites show evidence
  • that its members used fire and lived in caves,
  • an advantage for those living
  • in more northerly climates

100
Homo erectus Using Tools
  • Re-creation of a Pleistocene setting in Europe
  • in which members of Homo erectus are
  • using fire and stone tools

101
The "Out of Africa" View
  • Currently, a heated debate surrounds the
    transition
  • from H. erectus to our own species, Homo sapiens
  • Paleoanthropologists are split into two camps
  • On the one side are those who support
  • the "out of Africa" view
  • According to this camp, early modern humans
  • evolved from a single woman in Africa,
  • whose offspring then migrated from Africa,
  • perhaps as recently as 100,000 years ago
  • and populated Europe and Asia,
  • driving the earlier hominid populations to
    extinction

102
The "Multiregional" View
  • On the other side are those supporting the
    "multiregional" view
  • According to this hypothesis,
  • early modern humans did not have an isolated
    origin in Africa,
  • but rather established separate populations
    throughout Eurasia
  • Occasional contact and interbreeding
  • between these populations enabled our species to
    maintain its overall cohesiveness,
  • while still preserving the regional differences
  • in people we see today

103
Homo sapiens Evolved From H. erectus
  • Regardless of which theory turns out to be
    correct,
  • our species, H. sapiens
  • most certainly evolved from H. erectus

104
Neaderthals
  • Perhaps the most famous of all fossil humans are
    the Neanderthals,
  • who inhabited Europe and the Near East
  • from about 200,000 to 30,000 years ago
  • Some paleoanthropologists regard the Neanderthals
  • as a variety or subspecies of our own species
    (Homo sapiens neanderthalensis),
  • whereas others regard them as a separate species
    (Homo neanderthalensis)

105
Specimens Found in Neander Valley
  • In any case, their name comes
  • from the first specimens found in 1856
  • in the Neander Valley near Düsseldorf, Germany

106
Neanderthals Difference
  • The most notable difference between Neanderthals
  • and present-day humans is in the skull
  • Neanderthal skulls were long and low
  • with heavy brow ridges, a projecting mouth,
  • and a weak, receding chin
  • Their brain was slightly larger on average
  • than our own, and somewhat differently shaped

107
Neanderthal Skull
  • Reconstructed Neanderthal skull
  • The Neanderthals were characterized
  • by prominent heavy brow ridges and week chin

108
Cold Adapted
  • The Neanderthal body was
  • somewhat more massive
  • and heavily muscled
  • than ours,
  • with rather short lower limbs,
  • much like those
  • of other cold-adapted people of today

109
First Humans in Cold Climates
  • Given the specimens from more than 100 sites,
  • we now know Neanderthals
  • were not much different from us,
  • only more robust
  • Europe's Neanderthals were the first humans
  • to move into truly cold climates,
  • enduring miserably long winters and short summers
  • as they pushed north into tundra country

110
Burial Ceremony in a Cave
  • Archaeological evidence indicates
  • Neanderthals lived in caves
  • and participated in ritual burials
  • as depicted in this painting of a burial ceremony
  • such as occurred approximately 60,000 years ago
  • at Shanidar Cave, Iraq

111
Took Care of Their Injured
  • The remains of Neanderthals
  • are found chiefly in caves
  • and hutlike rock shelters,
  • which also contain a variety
  • of specialized stone tools and weapons
  • Furthermore, archaeological evidence indicates
  • that Neanderthals commonly
  • took care of their injured and buried their dead,
  • frequently with such grave items
  • as tools, food, and perhaps even flowers

112
Cro-Magnons
  • About 30,000 years ago,
  • humans closely resembling modern Europeans
  • moved into the region inhabited
  • by the Neanderthals and completely replaced them
  • Cro-Magnons, the name given to
  • the successors of the Neanderthals in France,
  • lived from about 35,000 to 10,000 years ago
  • during this period the development of art and
    technology
  • far exceeded anything the world had seen before

113
Nomadic Hunters
  • Highly skilled nomadic hunters,
  • Cro-Magnons followed the herds
  • in their seasonal migrations
  • They used a variety of specialized tools
  • in their hunts, including perhaps the bow and
    arrow
  • They sought refuge in caves and rock shelters
  • and formed living groups of various sizes

114
Cro-Magnon Camp
  • Re-creation of a Cro-Magnon camp in Europe

115
Cave Painters
  • Cro-Magnons were also cave painters
  • Using paints made from manganese and iron oxides,
  • Cro-Magnon people painted hundreds of scenes
  • on the ceilings and walls of caves
  • in France and Spain,
  • where many of them are still preserved today

116
Painting From a Cave in France
  • Cro-Magnons were very skilled cave painters
  • Painting of a horse
  • from the cave of Niaux, France

117
Cultural Evolution
  • With the appearance of Cro-Magnons,
  • human evolution has become
  • almost entirely cultural rather than biological
  • Humans have spread throughout the world
  • by devising means to deal with a broad range
  • of environmental conditions
  • Since the evolution of the Neanderthals
  • about 200,000 years ago,
  • humans have gone from a stone culture
  • to a technology that has allowed us
  • to visit other planets with space probes
  • and land astronauts on the Moon

118
Future
  • It remains to be seen
  • how we will use this technology in the future
  • and whether we will continue as a species,
  • evolve into another species,
  • or become extinct as many groups have before us

119
Summary
  • The primates evolved during the Paleocene
  • Several trends help characterize primate
  • and differentiate them from other mammalian
    orders,
  • including a change in overall skeletal structure
    and mode of locomotion
  • an increase in brain size
  • stereoscopic vision
  • and evolution of a grasping hand with opposable
    thumb

120
Summary
  • The primates are divided into two suborders
  • the prosimians and the anthropoids
  • The prosimians are the oldest primate lineage
  • and include lemurs, lorises, tarsiers, and tree
    shrews
  • The anthropoids include
  • the New and Old World monkeys,
  • apes,
  • and hominids, which are humans
  • and their extinct ancestors

121
Summary
  • The oldest known hominid is Sahelanthropus
    tchadensis,
  • dated at nearly 7 million years
  • then two subspecies of Ardipithecus at 5.8 and
    4.4 million years respectively
  • These early hominids were succeeded by the
    australopithecines
  • a fully bipedal group that evolved in Africa 4.2
    million years ago

122
Summary
  • Currently, five australopithecine species are
    known
  • Australopithecus anamensis, A. afarensis, A.
    africanus, A. robustus and A. boisei
  • The human lineage began
  • about 2.5 million years ago in Africa
  • with the evolution of Homo habilis,
  • which survived as a species
  • until about 1.6 million years ago
  • Homo erectus evolved from habilis
  • about 1.8 million years ago
  • and was the first hominid to migrate out of Africa

123
Summary
  • Between 1 and 1.8 million years ago, H. erectus
  • had spread to Europe, India, China, and Indonesia
  • H. erectus used fire, made tools, and lived in
    caves
  • Sometime between 200,000 and 100,000 years ago
  • Homo Sapiens evolved from H. erectus
  • These early humans may be ancestors of Neaderthals

124
Summary
  • Neanderthals were not much different
  • from present-day humans,
  • only more robust
  • and with differently shaped skulls
  • They made specialized tools and weapons,
  • apparently took care of their injured,
  • and buried their dead
  • The Cro-Magnons were the successors
  • of the Neanderthals
  • and lived from about 35,000-10,000 years ago

125
Summary
  • Cro-Magnons were highly skilled nomadic hunters,
  • formed living groups of various sizes,
  • and were also skilled cave painters
  • Modern humans succeeded the Cro-Magnons
  • about 10,000 years ago
  • and have spread throughout the world
Write a Comment
User Comments (0)
About PowerShow.com