Human Evolution 1 CH 32 - Outline Evolution of Primates Mobile Limbs Binocular Vision Evolution of Early Hominids Evolution of Later Hominids Evolution

Human Human EvolutionEvolution 1

CH 32 - OutlineCH 32 - Outline

Evolution of PrimatesEvolution of Primates

Mobile LimbsMobile Limbs

Binocular VisionBinocular Vision

Evolution of Early HominidsEvolution of Early Hominids

Evolution of Later HominidsEvolution of Later Hominids

Evolution of Early Evolution of Early HomoHomo

Modern HumansModern Humans

Human VariationHuman Variation



The evolution of primates is The evolution of primates is characterized by trends towards:characterized by trends towards:

Mobile limbsMobile limbs

Grasping handsGrasping hands

A flattened faceA flattened face

Binocular visionBinocular vision

A large, complex brain, andA large, complex brain, and

A reduced reproductive rateA reduced reproductive rate

3Primate Diversity

4Primate DiversityPrimate Diversity

ProsimiansProsimiansProsimians are a type of primate that include Prosimians are a type of primate that include

lemurs, lorises, bushbabies, and tarsiers, but not lemurs, lorises, bushbabies, and tarsiers, but not monkeys, apes, or humans (simians). monkeys, apes, or humans (simians).

They are considered to have characteristics that They are considered to have characteristics that are more "primitive" than those of monkeys and are more "primitive" than those of monkeys and apes.apes.

Prosimians are the only primates native to Prosimians are the only primates native to Madagascar, and are also found in Africa and Asia., and are also found in Africa and Asia.

http://en.wikipedia.org/wiki/Madagascar

New World MonkeysNew World monkeys differ slightly from Old

World monkeys in several aspects. The most distinction is the nose, which is the feature used most commonly to distinguish between the two groups. The scientific name for the New World monkeys, Platyrrhini, means "flat nosed".

New World monkeys are the only monkeys with prehensile tails—in comparison with the shorter, non-grasping tails of the anthropoids of the Old World.

Old World Monkeys

Old world monkeys are more closely related to apes than new world

monkeys

Old World MonkeysThe Old World monkeys are native to

Africa and Asia today, inhabiting a range of environments from tropical rain forest to savanna, shrubland and mountainous terrain, and are also known from Europe in the fossil record.

Old World monkeys are medium to large in size, and range from arboreal forms, such as the colobus monkeys, to fully terrestrial forms, such as the baboons.

Apes: African, Asia, and Human?


Mobile LimbsMobile Limbs

Hands and feetHands and feet

Most primates have flat nailsMost primates have flat nails

Sensitive pads on the undersides of Sensitive pads on the undersides of fingers and toesfingers and toes

Many also have both an opposable big Many also have both an opposable big toe and thumbtoe and thumb

Mobile limbs and clawless opposable Mobile limbs and clawless opposable digits allow primates to freely grasp digits allow primates to freely grasp and release tree limbsand release tree limbs

12Evolution of Primate Hand


Binocular VisionBinocular Vision

Stereoscopic visionStereoscopic vision

Depth perceptionDepth perception

Allows primates to make accurate Allows primates to make accurate judgments about distance and judgments about distance and position of adjoining tree limbsposition of adjoining tree limbs

14Binocular Vision


Primate CharacteristicsPrimate Characteristics

Opposable thumbOpposable thumb

Nails instead of clawsNails instead of claws

Single birthsSingle births

Binocular visionBinocular vision

Expanded, complex brainExpanded, complex brain

Emphasis on learned behaviorEmphasis on learned behavior



Prosimians were the first type of Prosimians were the first type of primate to diverge from the human primate to diverge from the human lineline

Surviving anthropoids are classified Surviving anthropoids are classified into three superfamiliesinto three superfamilies

New World monkeysNew World monkeys

Old World monkeysOld World monkeys

HominoidsHominoids

17Evolution of primates

Evolution of Primates


Evolution of HominidsEvolution of Hominids

ProconsulProconsul is believed ancestral to is believed ancestral to hominidshominids

Phylogenetic tree indicates humans Phylogenetic tree indicates humans are most closely related to African are most closely related to African apesapes

Genetic changes used as a molecular Genetic changes used as a molecular clock to measure relatedness of clock to measure relatedness of different groupsdifferent groups

Last common ancestor appears to Last common ancestor appears to have lived about 7 myahave lived about 7 mya

20Monkey SkeletonCompared to Proconsul

Skeleton


HominidsHominids

Hominid fossils:Hominid fossils:

Must have an anatomy suitable for Must have an anatomy suitable for standing erect and walking on two standing erect and walking on two feetfeet

BipedalismBipedalism

Skeletal differences between humans Skeletal differences between humans and apes largely because:and apes largely because:

Humans are bipedal, whileHumans are bipedal, while

Apes are quadrupedalApes are quadrupedal

22Adaptations for Standing1. Location of spine in skull

2. Human spine is S-shaped;

ape spine is curved.

3. Human pelvis is bowl shaped; ape pelvis is long and more narrow.

4. Humans femur angle in towards the knees; ape femurs angle out.

5. Human knees can support moreweight than ape knees.

6. Human foot has an arch; ape foothas no arch.


AustralopithecinesAustralopithecines

Australopithecines:Australopithecines:

Evolved and diversified in Africa 4 myaEvolved and diversified in Africa 4 mya

Possibly a direct ancestor of humansPossibly a direct ancestor of humans

Southern AfricaSouthern Africa

Australopithecus africanusAustralopithecus africanus

Eastern AfricaEastern Africa

Australopithecus afarensisAustralopithecus afarensis

24Human Evolution

Australopithecus afarensisThe specimen was The specimen was discovered in 1974 at discovered in 1974 at Hadar in the Awash Valley Hadar in the Awash Valley of Ethiopia’s Afar of Ethiopia’s Afar Depression by Donald Depression by Donald Johansson of the Cleveland Johansson of the Cleveland Museum of Natural HistoryMuseum of Natural HistoryLucy is estimated to have Lucy is estimated to have lived 3.2 million years ago.lived 3.2 million years ago.[[

The discovery of this The discovery of this hominid was significant as hominid was significant as the skeleton shows the skeleton shows evidence of small skull evidence of small skull capacity akin to that of capacity akin to that of apes and of bipedal apes and of bipedal upright walk akin to that of upright walk akin to that of humanshumansProviding further evidence Providing further evidence supporting the view that supporting the view that bipedalism preceded bipedalism preceded increase in brain size in increase in brain size in human evolutionhuman evolution

25

Named “Lucy” after Named “Lucy” after the Beatles song the Beatles song “Lucy in the Sky “Lucy in the Sky with Diamonds”with Diamonds”Several hundred Several hundred pieces of bone pieces of bone representing about representing about 40% of the skeleton40% of the skeleton

Australopithecus Australopithecus afarensisafarensis

26

http://upload.wikimedia.org/wikipedia/commons/d/da/Lucy_Skeleton.jpg


Evolution of Early Evolution of Early HomoHomo

Homo habilisHomo habilis

Dated between 2.3 and 1.4 myaDated between 2.3 and 1.4 mya

May be ancestral to modern humansMay be ancestral to modern humans

Skulls suggest portions of the brain Skulls suggest portions of the brain associated with speech were associated with speech were enlargedenlarged

Ability to speak may have led to Ability to speak may have led to hunting cooperatively and the advent hunting cooperatively and the advent of cultureof culture


Homo erectusHomo erectusHomo erectus Homo erectus and similar fossilsand similar fossils

Found in Africa, Asia, and EuropeFound in Africa, Asia, and Europe

Dated between 1.9 and 0.3 myaDated between 1.9 and 0.3 mya

Larger brain and flatter face than Larger brain and flatter face than Homo Homo habilishabilis

Much taller than previous hominidsMuch taller than previous hominids

Thought to have first appeared in Africa Thought to have first appeared in Africa and then migrated into Asia and Europeand then migrated into Asia and Europe

First hominid to use fireFirst hominid to use fire

29Homo ergaster


Evolution of Modern HumansEvolution of Modern Humans

Most researchers believe Most researchers believe Homo Homo sapienssapiens evolved from evolved from Homo erectusHomo erectus

Multiregional Continuity HypothesisMultiregional Continuity Hypothesis

Similar evolution occurred in many Similar evolution occurred in many different placesdifferent places

Out-of-Africa HypothesisOut-of-Africa Hypothesis

H. sapiensH. sapiens evolved from evolved from H. erectusH. erectus only only in Africa, and thereafter migrated to in Africa, and thereafter migrated to EuropeEurope

31Evolution of Modern Humans

Which of these makes more sense and why?


NeanderthalsNeanderthals

Neanderthal (Neanderthal (H. neanderthalensisH. neanderthalensis) ) skeletons were first discovered in skeletons were first discovered in Germany’s Neander ValleyGermany’s Neander Valley

Skeletons date back 200,000 yearsSkeletons date back 200,000 years

Massive brow ridges with protruding Massive brow ridges with protruding nose, jaws, and teethnose, jaws, and teeth

Heavily muscledHeavily muscled

Culturally advancedCulturally advanced

Manufactured variety of toolsManufactured variety of tools

33Neandertals


Cro-MagnonsCro-Magnons

Oldest fossils to be designated Oldest fossils to be designated H. H. sapienssapiens

Modern humans who entered Asia and Modern humans who entered Asia and Europe from Africa 100,000 years Europe from Africa 100,000 years agoago

Made advanced stone toolsMade advanced stone tools

Accomplished huntersAccomplished hunters

Hunted cooperativelyHunted cooperatively

First to have languageFirst to have language

35 Cro-Magnons


Human VariationHuman VariationHypothesized that human variations Hypothesized that human variations evolved as adaptations to local evolved as adaptations to local environmental conditionsenvironmental conditions

Bergmann’s Rule - Animals in colder regions Bergmann’s Rule - Animals in colder regions of their range have a bulkier body buildof their range have a bulkier body build

Allen’s Rule - Animals in colder regions of Allen’s Rule - Animals in colder regions of their range have shorter limbs, digits, and their range have shorter limbs, digits, and earsears

Comparative study of mitochondrial DNAComparative study of mitochondrial DNA

Suggests human populations have a Suggests human populations have a common ancestor no more than a million common ancestor no more than a million years agoyears ago

37 Ethnic Groups

Documents

Human Evolution 1 CH 32 - Outline Evolution of Primates Mobile Limbs Binocular Vision Evolution of Early Hominids Evolution of Later Hominids Evolution