Chapter19 Primate and Human Evolution

5/23/2018 Chapter19 Primate and Human Evolution

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Primate and Human Evolution

Chapter 19


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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

The Cradle of Mankind


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Who are we? Where did we come from?

What is the human genealogy?

These are basic questionsthat we all ask

Who are we?


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Many people enjoy tracingtheir 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

Goes Back Farther

Than We Thought


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In fact, a skull found in the African nation ofChad,

in 2002 and named Sahelanthropus tchadensis

but nicknamed Tourma,

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 2006provides strong evidence for

an ancestor-descendant relationship

between two early hominid lines, one of which leads to our own human heritage

Hope of Life


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So where does this leave us, evolutionarily

speaking?

At a very exciting time as we seek to unravel thehistory of our species

Our understanding of our genealogy

is presently in flux,

and each new fossil hominid find

sheds more light on our ancestry

Understanding in Flux


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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

Human Evolution


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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

New Hypotheses About

Our Ancestry


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As recently as 2000,

the earliest fossil evidence of hominids

was from 4.4-million-year-old rocks in easternAfrica

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

Continuing Discoveries

Change Our Ideas


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Primatesare 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

What Are Primates?


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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

Trends in Primates


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In fact, some primates

have retained certain primitive features,whereas others show all

or most of these trends

Variations


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The primate order is divided into two suborders

Theprosimians, or lower primates,

include the lemurs, lorises, tarsiers, and tree

shrews,

while the anthropoids, or higher primates,

include monkeys, apes, and humans

Classification of Primates


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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



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Prosimiansare 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

Prosimians


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Tarsiers areprosimianprimates

Tarsier


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Ring-TailedLemur arealsoprosimians

Ring-Tailed Lemur


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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 wereabundant, diversified, and widespread

in North America, Europe, and Asia

Prosimians


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Notharctus, a primitive Eocene prosimian

Eocene Prosimian

fromNorthAmerica


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As the continents moved northwardduring the Cenozoic

and the climate changed from warm tropical

to cooler midlatitude conditions,the prosimian population decreased

in both abundance and diversity

Prosimians Declined in Cooler

Climate


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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

Prosimians Are Tropical


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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.

Anthropoids


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New World Monkey

New World Monkeys constitute asuperfamily belonging to thesuborder Anthropoidea

(anthropoids)


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Another

superfamily of theanthropoids:

the Old Worldmonkeys

Old Word Monkey


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The third superfamilyis the great apes,

which include gorillasand...

Great Apes

hi


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Chimpanzees

Chimpanzees

l i f A h id


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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

Early History of Anthropoids

Th d f F il S i


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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,

wasAegyptopithecus,

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

Thousands of Fossil Specimens

O f h E li A h id


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One of the Earliest Anthropoids

Skull of

Aegyptopithecuszeuxis,

one of the earliestknown anthropoids


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Anthropoids are divided into three

superfamilies

Old World monkeys,

New World monkeys,

and hominoids

Anthropoid Superfamilies

Cl ifi i f P i


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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 W ld M k A ib


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Old World monkeys superfamily Cercopithecoidea

are characterized by close-set,

downward-directed nostrils

like those of apes and humansgrasping hands,

and a nonprehensile tail

They include

the macaque,

baboon,

and proboscis monkey

Old World Monkey Attributes

Old W d M k


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Superfamily

Cercopithecoidea the Old Worldmonkeys

Old Word Monkey


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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

Old World Monkeys Distribution


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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 Monkeys

N W ld M k


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New World Monkey

New World Monkeys aremembers of the superfamilyCeboidea

N C t t


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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

No Contact

H i id


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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

Hominoids


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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 includedAegyptopithecus

Hominoid Lineage

Cli ti Shift


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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

Climatic Shifts

Apes Adapted


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As the climate changed,

the primate populations also changed

Prosimians and monkeys became rare,

whereas hominoids diversified

in the newly forming environmentsand became abundant

Ape populations became reproductively

isolatedfrom each other within the various forests,

leading to adaptive radiation

and increased diversity among the hominoids

Apes Adapted


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During the Miocene,Africa collided with Eurasia,

producing additional changes in the climate,

as well as providing opportunitiesfor migration of animals

between the two landmasses

Migration of Animals Possible

Hominoid Relationships


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Two apelike groups evolved during the

Miocenethat ultimately gave rise to present-day hominoids

Although scientists still disagree

on the early evolutionary relationships among thehominoids,

fossil evidence and molecular DNA similarities

between modern hominoid families

is providing a clearer picture of the evolutionarypathways

and relationships among the hominoids

Hominoid Relationships


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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

Dryopithecines

P l


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The best-known dryopithecine and perhaps

ancestor of all later hominoids

isProconsul,

an ape-like fruit-eating animal

that led a quadrupedal arboreal existence,

with limited activity on the ground

The dryopithecines were very abundantand diverse during the Miocene and Pliocene,

particularly in Africa

Proconsul

Proconsul


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Proconsul

Probable appearance of Proconsul, a

dryopithecine


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The second group, the sivapithecids,

evolved in Africa during the Mioceneand 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

Sivapithecids Ate Harder Foods


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All sivapithecids had powerful jaws and teethwith 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 earlyHomo in Eastern Asia.

Sivapithecids Ate Harder Foods


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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

Two Lineages

Hominids


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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 theirskeleton

Hominids

Comparison of Locomotion


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Comparison betweenquadrupedal and

bipedal locomotionin gorillas and humans


In gorillas the ischium

bone is longand the entire pelvis is

tilted toward thehorizontal



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In humans the ischiumbone is much shorter

and the pelvis is vertical


Comparison betweenquadrupedal and

bipedal locomotionin gorillas and humans

Larger Reorganized Brain


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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




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a great ape



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a present-day

human


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Other features that distinguish hominids from

other hominoids includea reduced face

and reduced canine teeth,

omnivorous feeding,

increased manual dexterity,

and the use of sophisticated tools

Other Distinguishing Features

R Cli i Ch


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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

Response to Climatic Changes


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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

Mixed Forests and Grasslands

No Clear Consensus


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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

No Clear Consensus


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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

Some Current Theories

Stratigraphic Record


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The geologic ranges

for the commonly accepted species of hominids



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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

Debates


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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 timewhen humans diverged

from our closest-living relative, the chimpanzee

Oldest Known Hominid

Sahelanthropus tchadensis


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Discovered in

Chad in 2002

and dated at

nearly 7 million

years,

this skull is

presently

the oldest

known hominid

Sahelanthropus tchadensis


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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

When Humans and Chimpanzees

Diverged

Oldest Hominid


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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 ridgesare features only seen, until now,

in the human genusHomo

Oldest Hominid


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Sahelanthropus tchadensis may have been

bipedal in its walking habits,

but until bones from its legs and feet are found,

that supposition remains conjecture

Leg Bones and Feet Needed


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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 tugenensisfits in the

hominid lineage

Next Oldest Hominid

Ardipithecus ramidus


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Sometime between 5.8 and 5.2 million years

ago,

another hominid was present in eastern Africa

Ardipithecus ramidus kadabbais older

than its 4.4 million year old relative

Ardipithecus ramidus ramidus

Ardipithecus ramidus kadabbais very similar

in most features toArdipithecus ramidus ramidus

but in certain features of its teeth

is more apelike than its younger relative

Ardipithecus ramidus



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The geologic age ranges



Habitual Bipedal Walkers


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Although many paleoanthropologists think

both Orrorin tugenensisandArdipithecus ramiduskadabba

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

b u ped W e s

A t l ith i


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Australopithecineis a collective term

for all members of the genusAustralopithecus

Currently, five species are recognized:

A. anamensis,

A. afarensis,

A. africanus,

A. robustus,

and A. boisei

Australopithecines

E l ti S h


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Many paleontologists accept

the evolutionary scheme in which

A. anamensis, the oldest known australopithecine,

is ancestral toA. afarensis,

who in turn is ancestral toA. africanus

and the genusHomo,

as well as the side branch of australopithecines

represented byA. robustusandA. boisei

Evolutionary Scheme


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The oldest known australopithecine

isAustralopithecus anamensis

and was discovered at Kanapoi,

a site near Lake Turkana, Kenya,

by Meave Leakey

of the National Museums of Kenya

and her colleagues

Oldest Known Australopithecine

Similar Yet More Primitive


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A. anamensis,a 4.2-million-year-old bipedalspecies,

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


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A discovery in 2006 of fossils

ofA. anamensis,from the Middle Awash area in northeastern Ethiopia

has shed new light on the transition between

Ardipithecus andAustralopithecus.

The discovery ofArdipithecus

in the same region of Africa

and same times as the earliestAustralopithecus

provides strong evidence thatArdipithecus evolved intoAustralopithecus

and links these two genera

in the evolutionary lineage leading to humans.

y


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Australopithecus afarensis,

who lived 3.93.0 million years ago,

was fully bipedal

and exhibited great variability in size and weight

Members of this species rangedfrom just over 1 m to about 1.5 m tall


Australopithecus afarensis

Lucy


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A reconstruction of

Lucys skeleton

by Owen Lovejoy

and his students at Kent

State University, Ohio Lucy is an ~ 3.5-million-

year-old

Australopithecusafarensis

y

This

recon-struction

illustrates how adaptations in

Lucys hip, leg and foot

allowed a fully bipedal

means of locomotion

Hominid Footprints


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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 twoadults and possibly those

of a child

are clearly visible in this

photograph

p

Hominid Footprints


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p

Most scientists thinkthe footprints

were made by

Australopithecusafarensis

whose fossils are

found at Laetoli


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A. afarensishad 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)

Brain Size ofA. afarensis

Apelike Features


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The skull ofA. afarensisretained 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 molarswere probably an adaptation to chewing fruits,

seeds, and roots

Apelike Features

Landscape with A. afarensis


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p

Re-creation

of aPliocenelandscape

showingmembersof

Australo-pithecusafarensis

gatheringand eating

variousfruits andseeds

A. africanus Lived 3.02.3 mya


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A. afarensiswas succeeded byAustralopithecus africanus,

which lived 3.02.3 million years ago

The differences between the two species arerelatively minor

They were both about the same size and

weight,butA. africanushad a flatter face

and somewhat larger brain

A. africanus Lived 3.0 2.3 mya

Skull ofA. africanus


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A reconstruction of

the skullofAustralopithecus

africanus

This skull,

known as that of theTaung Child,

was discovered byRaymond Dart inSouth Africa in 1924

and marks thebeginning of modernpaleoanthropology


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It appears the limbs

ofA. africanusmay not have beenas well adapted for bipedalism

as those ofA. afarensis

Not As Well Adapted for

Bipedalism

Robust Species


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BothA. afarensisandA. africanus

differ markedly from the so-called robust species

A. boisei(2.61.0 million years ago)

andA. robustus(2.01.2 million years ago)

A. boiseiwas 1.21.4 m tall


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

Robust Species

A. robustus Was a Vegetarian


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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 skullhad an elevated bony crest

that provided additional area

for the attachment of strong jaw muscles Its broad flat molars indicated

A. robustuswas a vegetarian

. obustus Was a Vegeta a

Australopithecus robustus Skull


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The skull ofAustralopithecusrobustus

This species had amassive jaw,

powerful chewingmuscles,

and large broad

flat chewing teeth apparently used

for grinding upcoarse plant food


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Most scientists accept the idea

that the robust australopithecines

form a separate lineage

from the other australopithecines

that went extinct 1 million years ago

Separate Lineage

The Human Lineage


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Homo habilis

The earliest member of our own genusHomoisHomo 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. habilisevolved from theA. afarensisandA.africanuslineage

and coexisted withA. africanus

for about 200,000 years



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The geologic age ranges



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H. habilishad 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

Characteristics ofHomo habilis

Homo Erectus


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In contrast to the australopithecines andH.

habilis,

which are unknown outside Africa,

Homo erectuswas 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")

Homo Erectus


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H. erectusevolved in Africa 1.8 million years

ago

and by 1 million years agowas present in southeastern and eastern Asia,

where it survived until about 100,000 years ago

Survived in Asia Until About100,000 Years Ago

H erectus Differed From Modern


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AlthoughH. erectusdeveloped 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 ofH. habilis,

was still less than the average forHomo sapiens

(1350 cc)

H. erectus Differed From Modern

Humans

Size Similar to Humans


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H. erectus'sskull 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. erectuswas comparable to size to modern

humans,standing between 1.6 and 1.8 m tall

and weighing between 53 and 63 kg

S e S a to u a s

Skull ofHomo erectus


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A reconstruction ofthe skull ofHomo

erectus

a widelydistributed species

whose remains

have been found

in Africa, Europe,

India, China, and

Indonesia


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The archaeological record indicatesthatH. erectuswas 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

H. erectusWas a Tool Maker

Homo erectus Using Tools


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Recreation of a Pleistocene setting in Europe

in which members ofHomo erectusare

using fire and stone tools

The "Out of Africa" View


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Debate still surrounds the transition

fromH. erectusto our own species,Homo sapiensPaleoanthropologists are split into two camps

On the one side are those who supportthe "out of Africa" view

According to this camp, early modern humansevolved 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 toextinction

The "Multiregional" View


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On the other side are those supporting the

"multiregional" view According to this hypothesis,

early modern humans did not have an isolatedorigin in Africa,

but rather established separate populationsthroughout Eurasia

Occasional contact and interbreeding

between these populations enabled our species tomaintain its overall cohesiveness,

while still preserving the regional differences

in people we see today


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Regardless of which theory turns out to be

correct,our species,H. sapiens

most certainly evolved fromH. erectus

Homo sapiens Evolved

FromH. erectus

Neanderthals


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Perhaps the most famous of all fossil humans

are theNeanderthals,who inhabited Europe and the Near East

from about 200,000 to 30,000 years ago

Some paleoanthropologists regard theNeanderthals

as a variety or subspecies of our own species

(Homo sapiens neanderthalensis),whereas others regard them as a separate species

(Homo neanderthalensis)


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In any case, their name comesfrom the first specimens found in 1856

in the Neander Valley near Dsseldorf, Germany

Specimens Found in Neander

Valley

Neanderthals


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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

Neanderthals

Neanderthal Skull


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Reconstructed

Neanderthalskull

TheNeanderthals

were characterized

by prominent heavybrow ridges and weak chin


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The Neanderthal body was

more massiveand heavily muscled

than ours,

with rather short lower limbs,much like those

of other cold-adapted people of today

Cold Adapted

First Humans in Cold Climates


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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

First Humans in Cold Climates

Burial Ceremony in a Cave


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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 agoat Shanidar Cave, Iraq

Took Care of Their Injured


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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


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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 andtechnology

far exceeded anything the world had seen before


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Highly skilled nomadic hunters,

Cro-Magnons followed the herdsin 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

Nomadic Hunters

Cro-Magnon Camp


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Pleistocene Cro-Magnon camp in Europe


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Cro-Magnons were also cave painters

Using paints made from manganese and ironoxides,

Cro-Magnon people painted hundreds of scenes

on the ceilings and walls of cavesin France and Spain,

where many of them are still preserved today

Cave Painters

Painting From a Cave in France


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Cro-Magnons were very skilled cave painters

Painting of a horse

from the cave of Niaux, France

Cultural Evolution


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With the appearance of Cro-Magnons,

human evolution has becomealmost entirely cultural rather than biological

Humans have spread throughout the worldby 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


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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

Future

Summary


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Theprimatesevolved 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

Summary


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The primates are divided into two suborderstheprosimiansand the anthropoids

The prosimians are the oldest primate lineage

and include lemurs, lorises, tarsiers, and treeshrews

The anthropoids include

theNewand Old World monkeys,

apes,

and hominids, which are humans

and their extinct ancestors

Summary


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The oldest known hominid is Sahelanthropus

tchadensis, dated at nearly 7 million years

then two subspecies ofArdipithecusat 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 indicateArdipithecus evolved

intoAustralopithecus

Summary


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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 Africawith the evolution ofHomohabilis,

which survived as a species

until about 1.6 million years ago

Homoerectusevolved fromH. habilisabout 1.8 million years ago

and was the first hominid to migrate out of Africa

Summary


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Between 1 and 1.8 million years ago,H.

erectushad spread to Europe, India, China, and

Indonesia

H. erectusused fire, made tools, and livedin caves

Sometime between 200,000 and 100,000years ago

Homo sapiensevolved fromH. erectus

These early humans may be ancestors ofNeanderthals

Summary


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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-Magnonswere the successorsof the Neanderthals

and lived from about 35,000-10,000 years ago


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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-Magnonsabout 10,000 years ago

Chapter19 Primate and Human Evolution

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Transcript of Chapter19 Primate and Human Evolution