Chapter 19
Download
1 / 125

primate and human evolution - PowerPoint PPT Presentation


  • 684 Views
  • Updated On :

Chapter 19 . Primate and Human Evolution. The Cradle of Mankind. Olduvai Gorge on the eastern Serengeti Plain, Northern Tanzania is often referred to as “The Cradle of Mankind” because of many important hominid discoveries there. Who are we?. Who are we? Where did we come from?

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'primate and human evolution' - arleen


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Slide1 l.jpg

Chapter 19

Primate and Human Evolution


The cradle of mankind l.jpg
The Cradle of Mankind

  • Olduvai Gorge on the eastern Serengeti Plain,

    • Northern Tanzania

  • is often referred to as “The Cradle of Mankind”

    • because of many important hominid discoveries there


Who are we l.jpg
Who are we?

  • Who are we?

  • Where did we come from?

  • What is the human genealogy?

  • These are basic questions

    • that we all ask


Goes back farther than we thought l.jpg
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


Hope of life l.jpg
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

  • Another discovery reported in 2006

    • provides strong evidence for

    • an ancestor-descendant relationship

    • between two early hominid lines,

      • one of which leads to our own human heritage


Understanding in flux l.jpg
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


Human evolution l.jpg
Human Evolution

  • Apparently human evolution

    • is just like that of other groups

  • We have followed

    • an uncertain evolutionary path

  • As new species evolved,

    • they filled ecologic niches

    • and either gave rise to descendants

    • better adapted to the changing environment

    • or became extinct

  • Our own evolutionary history

    • has many dead-end side branches


New hypotheses about our ancestry l.jpg
New Hypotheses About Our Ancestry

  • 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


Continuing discoveries change our ideas l.jpg
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

  • In 2004, discoveries had pushed

    • that age back to almost 7 million years

  • Now, new findings in Ethiopia indicate

    • a direct link between two early hominid groups

    • that were previously thought to be closely related


What are primates l.jpg
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


Trends in primates l.jpg
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


Variations l.jpg
Variations

  • In fact, some primates

    • have retained certain primitive features,

    • whereas others show all

    • or most of these trends


Classification of primates l.jpg
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


Classification of primates14 l.jpg
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 (Old World monkeys)

      • Superfamily Ceboidea: Howler, spider, and squirrel monkeys (New World monkeys)

      • Superfamily Hominoidea: Apes, humans

        • Family Pongidae: Chimpanzees, orangutans, gorillas

        • Family Hylobatidae: Gibbons, siamangs

        • Family Hominidae: Humans


Prosimians l.jpg
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


Tarsier l.jpg
Tarsier

  • Tarsiers are prosimian primates


Ring tailed lemur l.jpg
Ring-Tailed Lemur

  • Ring-Tailed Lemur are also prosimians


Prosimians18 l.jpg
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


  • Eocene prosimian l.jpg
    Eocene Prosimian

    • Notharctus, a primitive Eocene prosimian

    • from North America


    Prosimians declined in cooler climate l.jpg
    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


    Prosimians are tropical l.jpg
    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


    Anthropoids l.jpg
    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.


    New world monkey l.jpg
    New World Monkey

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


    Old word monkey l.jpg
    Old Word Monkey

    • Another superfamily of the anthropoids:

    • the Old World monkeys


    Great apes l.jpg
    Great Apes

    • The third superfamily is the great apes,

      • which include gorillas and...


    Chimpanzees l.jpg
    Chimpanzees

    • Chimpanzees


    Early history of anthropoids l.jpg
    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


    Thousands of fossil specimens l.jpg
    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, about 5 kg

  • It had monkey characteristics and ape features

    • and is the closest link we currently have

    • to Old World primates


  • One of the earliest anthropoids l.jpg
    One of the Earliest Anthropoids

    • Skull of Aegyptopithecus zeuxis,

    • one of the earliest known anthropoids


    Anthropoid superfamilies l.jpg
    Anthropoid Superfamilies

    • Anthropoids are divided into three superfamilies

      • Old World monkeys,

      • New World monkeys,

      • and hominoids


    Classification of primates31 l.jpg
    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 (Old World monkeys)

        • Superfamily Ceboidea: Howler, spider, and squirrel monkeys (New World monkeys)

        • Superfamily Hominoidea: Apes, humans

          • Family Pongidae: Chimpanzees, orangutans, gorillas

          • Family Hylobatidae: Gibbons, siamangs

          • Family Hominidae: Humans


    Old world monkey attributes l.jpg
    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


  • Old word monkey33 l.jpg
    Old Word Monkey

    • Superfamily Cercopithecoidea

    • the Old World monkeys


    Old world monkeys distribution l.jpg
    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


    New world monkeys l.jpg
    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


  • New world monkey36 l.jpg
    New World Monkey

    • New World Monkeys are members of the superfamily Ceboidea


    No contact l.jpg
    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


    Hominoids l.jpg
    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


    Hominoid lineage l.jpg
    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


    Climatic shifts l.jpg
    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


    Apes adapted l.jpg
    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


    Migration of animals possible l.jpg
    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


    Hominoid relationships l.jpg
    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


    Dryopithecines l.jpg
    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


    Proconsul l.jpg
    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


    Proconsul46 l.jpg
    Proconsul

    • Probable appearance of Proconsul, a dryopithecine


    Sivapithecids l.jpg
    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 anatomy


    Sivapithecids ate harder foods l.jpg
    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 fossil evidence,

      • the sivapithecids were not involved

        • in the evolutionary branch leading to humans,

      • but were probably the ancestral stock

        • from which present-day orangutans evolved

      • In fact, one early genus, Gigantopithecus,

        • was a contemporary of early Homo in Eastern Asia.


    Two lineages l.jpg
    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


    Hominids l.jpg
    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


    Comparison of locomotion l.jpg
    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


    Comparison of locomotion52 l.jpg
    Comparison of Locomotion

    • In humans the ischium bone is much shorter

    • and the pelvis is vertical

    • Comparison between quadrupedal and bipedal locomotion

      • in gorillas and humans


    Larger reorganized brain l.jpg
    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


    Larger reorganized brain54 l.jpg
    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


    Larger reorganized brain55 l.jpg
    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


    Other distinguishing features l.jpg
    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


    Response to climatic changes l.jpg
    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


    Mixed forests and grasslands l.jpg
    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


    No clear consensus l.jpg
    No Clear Consensus

    • At present, no clear consensus exists

      • on the evolutionary history of the hominid lineage

    • This is partly because

      • 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


    Some current theories l.jpg
    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


    Stratigraphic record l.jpg
    Stratigraphic Record

    • The geologic ranges

      • for the commonly accepted species of hominids


    Debates l.jpg
    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


    Oldest known hominid l.jpg
    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


    Sahelanthropus tchadensis l.jpg
    Sahelanthropus tchadensis

    • Discovered in Chad in 2002

    • and dated at nearly 7 million years,

    • this skull is presently

    • the oldest known hominid


    When humans and chimpanzees diverged l.jpg
    When Humans and Chimpanzees Diverged

    • Currently, 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


    Oldest hominid l.jpg
    Oldest Hominid

    • Besides being the oldest hominid,

      • 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


    Leg bones and feet needed l.jpg
    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


    Next oldest hominid l.jpg
    Next Oldest Hominid

    • The next oldest hominid is Orrorin tugenensis,

      • whose fossils have been dated at 6 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


    Ardipithecus ramidus l.jpg
    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


    Stratigraphic record70 l.jpg
    Stratigraphic Record

    • The geologic age ranges

      • for the commonly accepted species of hominids


    Habitual bipedal walkers l.jpg
    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


    Australopithecines l.jpg
    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


    Evolutionary scheme l.jpg
    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


    Oldest known australopithecine l.jpg
    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


    Similar yet more primitive l.jpg
    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


    New fossil discovery l.jpg
    New Fossil Discovery

    • A discovery in 2006 of fossils

      • of A. anamensis, from the Middle Awash area

        • in northeastern Ethiopia

      • has shed new light on the transition between

      • Ardipithecus and Australopithecus.

    • The discovery of Ardipithecus

      • in the same region of Africa

        • and same times as the earliest Australopithecus

      • provides strong evidence that Ardipithecus

        • evolved into Australopithecus

      • and links these two genera

      • in the evolutionary lineage leading to humans.


    Australopithecus afarensis l.jpg
    Australopithecus afarensis

    • Australopithecus afarensis,

      • who lived 3.9–3.0 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


    Slide78 l.jpg
    Lucy

    • This recon-struction

    • illustrates how adaptations in

    • Lucy’s hip, leg and foot

    • allowed a fully bipedal

    • means of locomotion

    • A reconstruction of Lucy’s skeleton

      • by Owen Lovejoy

        • and his students at Kent State University, Ohio

    • Lucy is an ~ 3.5-million-year-old

      • Australopithecusafarensis


    Hominid footprints l.jpg
    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


    Hominid footprints80 l.jpg
    Hominid Footprints

    • Most scientists think the footprints

      • were made by Australopithecus afarensis

      • whose fossils are found at Laetoli


    Brain size of a afarensis l.jpg
    Brain Size of A. afarensis

    • A. afarensis had a brain size of 380–450 cubic centimeters (cc),

      • larger than the 300–400 cc

      • of a chimpanzee

      • but much smaller than that of present-day humans (1350 cc average)


    Apelike features l.jpg
    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


    Landscape with a afarensis l.jpg
    Landscape with A. afarensis

    • Re-creation of a Pliocene landscape

      • showing members of

      • Australo-pithecus afarensis

      • gathering and eating

      • various fruits and seeds


    A africanus lived 3 0 2 3 mya l.jpg
    A. africanus Lived 3.0–2.3 mya

    • A. afarensis was succeeded by

      • Australopithecus africanus,

      • which lived 3.0–2.3 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


    Skull of a africanus l.jpg
    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


    Not as well adapted for bipedalism l.jpg
    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


    Robust species l.jpg
    Robust Species

    • Both A. afarensis and A. africanus

      • differ markedly from the so-called robust species

        • A. boisei (2.6–1.0 million years ago)

        • and A. robustus (2.0–1.2 million years ago)

    • A. boisei was 1.2–1.4 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


    A robustus was a vegetarian l.jpg
    A. robustus Was a Vegetarian

    • A. robustus, in contrast,

      • was somewhat smaller (1.1–1.3 m tall)

      • and lighter (32–40 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


    Australopithecus robustus skull l.jpg
    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


    Separate lineage l.jpg
    Separate Lineage

    • Most scientists accept the idea

      • that the robust australopithecines

      • form a separate lineage

      • from the other australopithecines

      • that went extinct 1 million years ago


    The human lineage l.jpg
    The Human Lineage

    Homo habilis

    • The earliest member of our own genus Homo

      • is Homo habilis,

      • who lived 2.5-1.6 million years ago

    • Its remains were first found at Olduvai Gorge,

      • Tanzania,

    • 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


  • Stratigraphic record92 l.jpg
    Stratigraphic Record

    • The geologic age ranges

      • for the commonly accepted species of hominids


    Characteristics of homo habilis l.jpg
    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


    Homo erectus l.jpg
    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")


    Survived in asia until about 100 000 years ago l.jpg
    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


    H erectus differed from modern humans l.jpg
    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)


    Size similar to humans l.jpg
    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 modern humans,

      • standing between 1.6 and 1.8 m tall

      • and weighing between 53 and 63 kg


    Skull of homo erectus l.jpg
    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


    H erectus was a tool maker l.jpg
    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


    Homo erectus using tools l.jpg
    Homo erectus Using Tools

    • Recreation of a Pleistocene setting in Europe

      • in which members of Homo erectus are

      • using fire and stone tools


    The out of africa view l.jpg
    The "Out of Africa" View

    • Debate still 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


    The multiregional view l.jpg
    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


    Homo sapiens evolved from h erectus l.jpg
    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


    Neanderthals l.jpg
    Neanderthals

    • 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)


    Specimens found in neander valley l.jpg
    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


    Neanderthals106 l.jpg
    Neanderthals

    • 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


    Neanderthal skull l.jpg
    Neanderthal Skull

    • Reconstructed Neanderthal skull

    • The Neanderthals were characterized

    • by prominent heavy brow ridges and weak chin


    Cold adapted l.jpg
    Cold Adapted

    • The Neanderthal body was

      • more massive

      • and heavily muscled

      • than ours,

      • with rather short lower limbs,

      • much like those

      • of other cold-adapted people of today


    First humans in cold climates l.jpg
    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


    Burial ceremony in a cave l.jpg
    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


    Took care of their injured l.jpg
    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


    Cro magnons l.jpg
    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


    Nomadic hunters l.jpg
    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


    Cro magnon camp l.jpg
    Cro-Magnon Camp

    • Pleistocene Cro-Magnon camp in Europe


    Cave painters l.jpg
    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


    Painting from a cave in france l.jpg
    Painting From a Cave in France

    • Cro-Magnons were very skilled cave painters

      • Painting of a horse

      • from the cave of Niaux, France


    Cultural evolution l.jpg
    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


    Future l.jpg
    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


    Summary l.jpg
    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


    Summary120 l.jpg
    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


    Summary121 l.jpg
    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

    • Recent discoveries indicate Ardipithecus evolved into Australopithecus


    Summary122 l.jpg
    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

    • Homoerectus evolved from H. habilis

      • about 1.8 million years ago

      • and was the first hominid to migrate out of Africa


    Summary123 l.jpg
    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 Neanderthals


    Summary124 l.jpg
    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


    Summary125 l.jpg
    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


    ad