Hominid EvolutionHominid Evolution

Origins of HominidsOrigins of Hominids

◊ Most crucial change was Bipedal Locomotion

◊ Other changes include• Expansion of the brain, larger birth

canal, reduction of face, teeth and jaws◊ All of these occurred 2 million yrs. After

bipedalism

◊ Journal Entry 1

◊ Most crucial change was Bipedal Locomotion

◊ Other changes include• Expansion of the brain, larger birth

canal, reduction of face, teeth and jaws◊ All of these occurred 2 million yrs. After

bipedalism

◊ Journal Entry 1

Why did Bipedalism occur?Why did Bipedalism occur?

◊ See farther◊ Carry food◊ Carry tools and weapons

◊ See farther◊ Carry food◊ Carry tools and weapons

AustralopithecinesAustralopithecines

◊ First definite Hominids◊ Genus of Hominids until C. 2 Mill yrs.

Ago◊ Somewhere b/t 3 and 4 mill. yrs ago. ◊ At Laetoli footprints found proving

bipedal locomotion◊ Although Bipedal, still may have

spent time in trees for sleep and shelter

◊ First definite Hominids◊ Genus of Hominids until C. 2 Mill yrs.

Ago◊ Somewhere b/t 3 and 4 mill. yrs ago. ◊ At Laetoli footprints found proving

bipedal locomotion◊ Although Bipedal, still may have

spent time in trees for sleep and shelter

Types of SpeciesTypes of Species

◊ Australopithecus afarensis◊ Australopithecus africanus◊ Australopithecus robustus◊ There are more Think of

hominids as a Bush, not a timeline!

◊ Australopithecus afarensis◊ Australopithecus africanus◊ Australopithecus robustus◊ There are more Think of

hominids as a Bush, not a timeline!

Australopithecus AfarensisAustralopithecus Afarensis

◊ Debate as to whether diff. species or not

◊ Footprints found to prove bipedalism

◊ Between 3 and 4 million years ago

◊ Debate as to whether diff. species or not

◊ Footprints found to prove bipedalism

◊ Between 3 and 4 million years ago

Australopithecus AfricanusAustralopithecus Africanus

◊ Jaw of ape◊ Teeth of humans◊ S-shape spine similar to man

◊ Jaw of ape◊ Teeth of humans◊ S-shape spine similar to man

Afarensis vs. AfricanusAfarensis vs. Africanus

◊ Features of skull, teeth, and jaws that are less apelike in africanus

◊ Some debate different species

◊ Features of skull, teeth, and jaws that are less apelike in africanus

◊ Some debate different species

Australopithecus robustusAustralopithecus robustus

◊ 2-1 million years ago◊ Larger molars and premolars◊ Smaller canines◊ Well-developed cranial crests and ridges◊ Much heavier◊ Taller: 4.5- 5 ft. tall

◊ 2-1 million years ago◊ Larger molars and premolars◊ Smaller canines◊ Well-developed cranial crests and ridges◊ Much heavier◊ Taller: 4.5- 5 ft. tall

Ancestor?Ancestor?

◊ Australopithecus robustus is not thought to be an ancestor to the Homo species

◊ Lived during same relative time as Homo species

◊ Australopithecus robustus is not thought to be an ancestor to the Homo species

◊ Lived during same relative time as Homo species

ChangesChanges

◊ Expansion of brain◊ Reduction of face, teeth, and jaws◊ Babies born less mature at birth

◊ Journal Entry #2

◊ Expansion of brain◊ Reduction of face, teeth, and jaws◊ Babies born less mature at birth

◊ Journal Entry #2

Expansion of the brainExpansion of the brain

◊ Had relatively small cranial capacities

◊ Reason?• Why would brain size have increased?

(Think Evolution types)

◊ Possible reasons:• Increased as a result of tool making

◊ Had relatively small cranial capacities

◊ Reason?• Why would brain size have increased?

(Think Evolution types)

◊ Possible reasons:• Increased as a result of tool making

Reduction of Face, Teeth, and JawsReduction of Face, Teeth, and Jaws◊ Lower face not as protruding◊ Reduction in size of

• Face• Cheek bone• Jaw

◊ Lower face not as protruding◊ Reduction in size of

• Face• Cheek bone• Jaw

Now on to species of HomoNow on to species of Homo◊ Different ideas on how Homo

genus evolved◊ Some say from Africanus◊ Some say from Afarensis◊ About 2 millions years ago

◊ Different ideas on how Homo genus evolved

◊ Some say from Africanus◊ Some say from Afarensis◊ About 2 millions years ago

Homo habilisHomo habilis

◊ Larger brain absolutely and relatively than Australopithecus

◊ Found in East Africa◊ Slightly Larger and more

developed brain◊ Stone tools?

◊ Larger brain absolutely and relatively than Australopithecus

◊ Found in East Africa◊ Slightly Larger and more

developed brain◊ Stone tools?

Homo erectusHomo erectus

◊ 1.6 to 1.3 millions years ago◊ Skull generally long, low, and

thickly walled◊ Flat frontal face◊ Prominent brow ridges◊ Relatively small teeth modern

arrangement

◊ 1.6 to 1.3 millions years ago◊ Skull generally long, low, and

thickly walled◊ Flat frontal face◊ Prominent brow ridges◊ Relatively small teeth modern

arrangement

Cont…Cont…

◊ Fully developed vision area of brain

◊ Larger areas of speech, sensory, memory and motor areas of brain

◊ Neck down, almost same as Homo sapiens

◊ Fully developed vision area of brain

◊ Larger areas of speech, sensory, memory and motor areas of brain

◊ Neck down, almost same as Homo sapiens

FireFire

◊ Fire first appears 1.5 mill. Years ago

◊ Only able to spread out after development of fire

◊ Journal Entry

◊ Fire first appears 1.5 mill. Years ago

◊ Only able to spread out after development of fire

◊ Journal Entry

Stone toolsStone tools

◊ Acheulean “hand axe”• 1.5 mil. Years ago• Used for butchering, digging,

pounding

◊ Toolmaker first shaped the core, and prepared a striking platform at one end

◊ Knock off flakes

◊ Acheulean “hand axe”• 1.5 mil. Years ago• Used for butchering, digging,

pounding

◊ Toolmaker first shaped the core, and prepared a striking platform at one end

◊ Knock off flakes

HuntingHunting

◊ Homo erectus began to hunt medium sized animals• Spears, stone throwing, and fire• Needed to plan and work in groups

◊ Homo erectus began to hunt medium sized animals• Spears, stone throwing, and fire• Needed to plan and work in groups

Neanderthal Neanderthal

◊ Becoming Human◊ Becoming Human