The Evolution of Primates Chapter 22. Learning Objective 1 What structural adaptations do primates...

The Evolution of PrimatesThe Evolution of Primates

Chapter 22Chapter 22

Learning Objective 1Learning Objective 1

• What structural adaptations do primates What structural adaptations do primates have for life in treetops?have for life in treetops?

Primates (1)Primates (1)

• Placental mammals Placental mammals • evolvedevolved from from arborealarboreal shrewlike mammals shrewlike mammals

• Five grasping digitsFive grasping digits• including including opposable thumbopposable thumb or toe or toe

Five Grasping DigitsFive Grasping Digits

Fig. 22-1a, p. 467

Hand Foot

(a) Lemur (Eulemur mongoz)

Fig. 22-1b, p. 467

Hand Foot

(b) Tarsier (Tarsius spectrum)

Fig. 22-1c, p. 467

Hand Foot

(c) Woolly spider monkey (Brachyteles arachnoides)

Fig. 22-1d, p. 467

Hand Foot

(d) Gorilla (Gorilla gorilla)

Primates (2)Primates (2)

• Long, slender limbsLong, slender limbs• move freely at hips and shouldersmove freely at hips and shoulders

• Eyes located in front of headEyes located in front of head

Learning Objective 2Learning Objective 2

• What are the three suborders of primates?What are the three suborders of primates?

• Give representative examples of eachGive representative examples of each

Suborders of PrimatesSuborders of Primates

• Prosimii Prosimii • lemurs, galagos, and loriseslemurs, galagos, and lorises

• TarsiiformesTarsiiformes• tarsiers tarsiers

• Anthropoidea (anthropoids)Anthropoidea (anthropoids)• monkeys, apes, and humansmonkeys, apes, and humans

Primate EvolutionPrimate Evolution

Fig. 22-2, p. 468

Suborder Prosimii

Suborder Tarsiiformes Suborder Anthropoidea

New World monkeys

Old World monkeysLemurs Tarsiers

GibbonsOrangutans

Gorillas

Chimpanzees

32

1Common hominoid ancestor

Common anthropoid ancestor

Common primate ancestor

Hominoids (Anthropoids)

Humans

KEY CONCEPTSKEY CONCEPTS

• Humans are classified in the order Humans are classified in the order Primates, along with lemurs, tarsiers, Primates, along with lemurs, tarsiers, monkeys, and apesmonkeys, and apes

• This classification is based on close This classification is based on close evolutionary tiesevolutionary ties

Learn more about primate Learn more about primate evolution by clicking on the evolution by clicking on the

figure in ThomsonNOW.figure in ThomsonNOW.

Learning Objective 3Learning Objective 3

• What is the difference between What is the difference between anthropoidsanthropoids, , hominoidshominoids, and , and hominidshominids??

AnthropoidsAnthropoids

• Include monkeys, apes, and humansInclude monkeys, apes, and humans

• Branched into 2 groups: Branched into 2 groups: • New World monkeysNew World monkeys• Old World monkeysOld World monkeys

New World and Old World MonkeysNew World and Old World Monkeys

HominoidsHominoids

• Include apes and humansInclude apes and humans• arose from Old World monkey lineagearose from Old World monkey lineage

• 4 modern genera of apes:4 modern genera of apes:• gibbonsgibbons• orangutansorangutans• gorillasgorillas• chimpanzeeschimpanzees

Ape Ape EvolutionEvolution

Fig. 22-5a/c, p. 470

(a) Fossils of Aegyptopithecus, a fairly primitive anthropoid, were discovered in Egypt.

(c) Dryopithecus, a more advanced ape, may have been ancestral to modern hominoids.

ApesApes

Fig. 22-6a, p. 471

Fig. 22-6b, p. 471

Fig. 22-6c, p. 471

Fig. 22-6d, p. 471

HominidsHominids

• Humans and their ancestorsHumans and their ancestors

KEY CONCEPTSKEY CONCEPTS

• The study of living primates provides clues The study of living primates provides clues to help scientists reconstruct the to help scientists reconstruct the adaptations and lifestyles of early adaptations and lifestyles of early primates, some of which were ancestors of primates, some of which were ancestors of humanshumans

Learning Objective 4Learning Objective 4

• What are the skeletal and skull differences What are the skeletal and skull differences between between apesapes and and hominidshominids??

Hominid SkeletonsHominid Skeletons

• Adaptations for standing erect and walking Adaptations for standing erect and walking on two feeton two feet• complex curvature of the spinecomplex curvature of the spine• short, broad pelvisshort, broad pelvis• foramen magnumforamen magnum at base of skull at base of skull• first toe aligned with other toesfirst toe aligned with other toes

Gorilla and Human SkeletonsGorilla and Human Skeletons

Fig. 22-7, p. 472

Simply curved spine

Foramen magnum at the center base of skull

Complex curvature of human spineForamen magnum

at the center rear of skull

Tall, narrow pelvis (front view)

Shorter, broader pelvis (front view)

First toe not opposable, and all toes aligned

First toe not aligned with others

Gorilla skeleton Human skeleton

Human SkeletonHuman Skeleton

• Human skullHuman skull• lacks pronounced lacks pronounced supraorbital ridgesupraorbital ridge• flatter than ape skulls in frontflatter than ape skulls in front• has a pronounced chinhas a pronounced chin• larger brain than apes larger brain than apes • jaw structure with teeth arranged in U shapejaw structure with teeth arranged in U shape

Human Human SkullSkull

Fig. 22-8a, p. 473

Supraorbital ridge

Incisors

Rectangular shape

Fig. 22-8b, p. 473

Incisors

U-shape

KEY CONCEPTSKEY CONCEPTS

• The human brain did not begin to enlarge The human brain did not begin to enlarge to its present size and complexity until to its present size and complexity until long after human ancestors had evolved long after human ancestors had evolved bipedal locomotionbipedal locomotion

Learn more about monkey, Learn more about monkey, gorilla, and human skeletons by gorilla, and human skeletons by

clicking on the figure in clicking on the figure in ThomsonNOW.ThomsonNOW.

Learning Objective 5Learning Objective 5

• Describe the following early hominids: Describe the following early hominids: Sahelanthropus, Orrorin, Ardipithecus Sahelanthropus, Orrorin, Ardipithecus ramidusramidus, , and and Australopithecus anamensis, Australopithecus anamensis, A. afarensis,A. afarensis, and and A. africanusA. africanus

SahelanthropusSahelanthropus

• Hominid EvolutionHominid Evolution began in Africa began in Africa• 6 to 7 million years ago 6 to 7 million years ago

• SahelanthropusSahelanthropus• small brainsmall brain• face and teeth had many characteristics of face and teeth had many characteristics of

larger brained human ancestorslarger brained human ancestors

OrrorinOrrorin

• Early hominidEarly hominid• about 6 mya about 6 mya

• OrrorinOrrorin • probably walked upright and was bipedalprobably walked upright and was bipedal• based on fossil leg bones based on fossil leg bones

Australopithecines (1)Australopithecines (1)

• IncludeInclude • ArdipithecusArdipithecus and and AustralopithecusAustralopithecus speciesspecies

• AustralopithecusAustralopithecus speciesspecies• bipedalbipedal (a hominid feature) (a hominid feature)

Australopithecines (2)Australopithecines (2)

• Ardipithecus ramidusArdipithecus ramidus• about 5.8 mya to 5.2 myaabout 5.8 mya to 5.2 mya

• Australopithecus anamensisAustralopithecus anamensis

• Australopithecus afarensisAustralopithecus afarensis

• Australopithecus africanusAustralopithecus africanus

Genus Genus HomoHomo

• Genus Genus AustralopithecusAustralopithecus contains the contains the immediate ancestors of genus immediate ancestors of genus HomoHomo

Possible Possible Evolutionary Evolutionary RelationshipsRelationships

Fig. 22-9, p. 473

H. sapiens H. neanderthalensis

Archaic H. sapiens

H. erectusA. boisei

A.

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tus

H. ergaster

H. habilisA. aethiopicus

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A. africanusM

illi

on

s o

f ye

ars

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A. afarensis

A. anamensis

A. ramidus ArdipithecusAustralopithecus

Homo

Fig. 22-9, p. 473

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Mil

lio

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of

year

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mya

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H. sapiens H. neanderthalensis

Archaic H. sapiens

H. erectus

H. ergaster

H. habilis

Homo

A. ramidus Ardipithecus

A. boisei

A.

rob

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tus

A. aethiopicus

A. africanus

A. afarensis

A. anamensis

Australopithecus

Stepped Art

Learning Objective 6Learning Objective 6

• Distinguish among the following members Distinguish among the following members of genus of genus HomoHomo: : H. habilis, H. ergaster, H. H. habilis, H. ergaster, H. erectus, H. neanderthalensiserectus, H. neanderthalensis, , and and H. H. sapienssapiens

Homo habilisHomo habilis

• Earliest known hominid with some human Earliest known hominid with some human features lacking in australopithecinesfeatures lacking in australopithecines• including slightly larger brain including slightly larger brain

• H. habilisH. habilis fashioned crude tools from stonefashioned crude tools from stone

Homo erectus Homo erectus (1)(1)

• Larger brain than Larger brain than H. habilisH. habilis• made more made more

sophisticated toolssophisticated tools• may have worn may have worn

clothing, built fires, clothing, built fires, lived in caves or lived in caves or sheltersshelters

Fig. 22-10, p. 475

Pronounced supraorbital ridge

Receding forehead

Projecting face/jaws

Homo erectus Homo erectus (2)(2)

• FossilsFossils may actually be 2 speciesmay actually be 2 species

• Homo ergasterHomo ergaster • earlier African speciesearlier African species• gave rise to archaic gave rise to archaic H. sapiensH. sapiens

• H. erectusH. erectus• later Asian offshootlater Asian offshoot• may be evolutionary dead endmay be evolutionary dead end

Archaic Archaic Homo sapiensHomo sapiens

• Regionally diverse descendants of Regionally diverse descendants of H. H. erectus erectus oror H. ergasterH. ergaster • in Africa, Asia, and Europein Africa, Asia, and Europe• about 400,000 to 200,000 years agoabout 400,000 to 200,000 years ago

• Brains about same size as our brainsBrains about same size as our brains• skulls retained some ancestral charactersskulls retained some ancestral characters• rich and varied culturesrich and varied cultures

NeandertalsNeandertals

• 230,000 to 30,000 years ago230,000 to 30,000 years ago

• Short, sturdy buildsShort, sturdy builds• receding chins and foreheadsreceding chins and foreheads• heavy supraorbital ridges and jawbonesheavy supraorbital ridges and jawbones• large front teethlarge front teeth• nasal cavities with triangular bony projections nasal cavities with triangular bony projections

Neandertal Neandertal ToolsTools

Homo sapiensHomo sapiens

• AAnatomically modern humansnatomically modern humans• in Africa about 195,000 years ago in Africa about 195,000 years ago

• Only members of genus Only members of genus HomoHomo remainingremaining• about 30,000 years agoabout 30,000 years ago

Cro-MagnonsCro-Magnons

• Ancient Ancient Homo sapiens Homo sapiens in in EuropeEurope

KEY CONCEPTSKEY CONCEPTS

• Fossil evidence indicates that the earliest Fossil evidence indicates that the earliest hominids (human ancestors) evolved in hominids (human ancestors) evolved in Africa and shared many features with their Africa and shared many features with their apelike ancestorsapelike ancestors

Learn more about Learn more about Homo Homo skulls skulls by clicking on the figure in by clicking on the figure in

ThomsonNOW.ThomsonNOW.

Learning Objective 7Learning Objective 7

• Discuss the origin of modern humansDiscuss the origin of modern humans

Origin of Modern Humans (1)Origin of Modern Humans (1)

• Out-of-Africa HypothesisOut-of-Africa Hypothesis • Modern Modern H. sapiensH. sapiens arose in Africa arose in Africa • migrated to Europe and Asiamigrated to Europe and Asia• displaced more primitive humans living theredisplaced more primitive humans living there

• Supported by recent fossil discoveries and Supported by recent fossil discoveries and molecular data molecular data

Origin of Modern Humans (2)Origin of Modern Humans (2)

• Multiregional hypothesisMultiregional hypothesis• Modern humans originated as separately Modern humans originated as separately

evolving populations of evolving populations of H. erectusH. erectus in Africa, in Africa, Asia, and EuropeAsia, and Europe

• Populations occasionally interbred, preventing Populations occasionally interbred, preventing complete reproductive isolationcomplete reproductive isolation

KEY CONCEPTSKEY CONCEPTS

• Human culture began when human Human culture began when human ancestors started making stone toolsancestors started making stone tools

Learning Objective 8Learning Objective 8

• What is the impact of human culture on What is the impact of human culture on the biosphere?the biosphere?

Human ImpactsHuman Impacts

• Large human brain sizeLarge human brain size• transmission of knowledge from one transmission of knowledge from one

generation to the next generation to the next

• 2 significant advances in human culture2 significant advances in human culture• development of agriculturedevelopment of agriculture• Industrial RevolutionIndustrial Revolution