Hominin Evolution - Hominids and Hominins

•Aims:

•Must be able to outline the characteristics

of Hominids, Apes and Hominins.

•Should be able to state the main

Australopithecines and their main features.

•Could be able to compare and contrast the

main forms of Australopithecines.

The Hominids• Includes: Great Apes and hominins

•Anatomical features common to all hominoids:

•No tail

•Semi-erect or fully erect posture

•Broad chest, pelvis, and shoulders

•Relatively long arms and mobile shoulder joints

•Large brain

Australopithecus afarensis

Chimpanzee

The Apes• Anatomical features and habits:

• Brachiating (swing underneath from branch to branch)

• Some mainly ground dwellingand quadrupedal (e.g. gorilla)

• Arms longer than legs

• Flattened nose

• Bony eye ridges

• No tail

Gibbon

Gibbon

Chimpanzee

Chimpanzee

Gorilla

Gorilla

Orangutan

Orangutan

Hominins• Anatomical features and habits:

• Bipedal with modified feet, thigh bone, pelvis, and spine

• Large cerebral cortex (forebrain)

• Reduced canines (and teeth in general)

• Prominent nose and chin, reduced eye ridges

• Body hair short or very reduced to assist cooling

• Highly sensitive skin

• Complex social behavior

• Examples:

• Australopithecus

• Paranthropus

• Homo

• Ardipithecus?

Paranthropus boisei Homo neanderthalensis Homo sapiens

Includes modern humans, extinct

human species and immediate ancestors.

Early Hominids• Since the mid

1990s a considerable number of new, early hominid species have been discovered:

Symbol Hominid Age (mya)

Sahelanthropus tchadensis 6.0 -7.0

Orrorin tugenensis 6.0

Ardipithecus ramidus 4.4 - 5.8

Australopithecus anamensis

3.9 - 4.2

Kenyanthropus platyops 3.5

Australopithecus bahrelghazali

3.5 - 3.0

Australopithecus garhi 2.5

Sahelanthropus tchadensis

Kenyanthropus platyops

Photos courtesy of: SkullsUnlimited.com

Some Famous Hominin Fossils..

The Australopithecines

•The main forms are:

•Australopithecus afarensis

•Australopithecus africanus

•Kenyanthropus platyops

• There is good fossil evidence that four kinds of hominid lived about 1.8 mya in what is now part of northern Kenya.

• They foraged in the same area around Lake Turkana.

• We have no idea how, or if, these different species interacted.

Once We Were Not Alone

P. boisei H. habilis H. rudolphensis H. ergaster

Genus Homo

Homo sapiens130,000 yrs ago - Present

Africa and western Asia, then global

Homo neanderthalensis150,000 - 30,000 yrs agoEurope and western Asia

Archaic Homo sapiens 400,000 - 100,000 yrs ago

Africa, Asia and Europe

Homo erectus1.8 M - 300,000 yrs ago

Africa, Asia, Indonesia andpossibly Europe

Homo habilis2.4 M - 1.6 M yrs agoEastern, and possibly

Southern Africa

Homo ergaster1.8 M - 1.4 M yrs ago

Africa, possiblyWestern Asia

Genus Homo

•The main forms are:

•Homo habilis

•Homo erectus

•Homo heidelbergensis

•Homo neanderthalensis

•Homo floresiensis

•Homo sapiens

The Effect of Continental Drift

• Early primates emerged in a world that was undergoing great change due to continental drift.

• During the Paleocene and Eocene, the continents were breaking up and taking on their present shapes and positions.

• Shifting continents affected climates, vegetation, and habitats for the evolving primates.

Late Paleozoic250 million years ago

The ancestors of the mammals were

still in the early stages of evolving

The Effect of Continental Drift

• Paleocene-Mid Eocene65-46 million years ago

• Early primates were distributed throughout North America and Europe (because the continents were joined)

• Primates were absent from Asia until the late Eocene (separated from Europe by Turgai Strait)

Turgai Strait

Madagascar

The Effect of Continental Drift

• Later Eocene46-38 million years ago

• North America separated from Europe

• Europe joined onto Asia and Africa

• Primates in North America were isolated and evolved without competition

• New primates emerged in Africa, Asia, Europe: the Old World monkeys, apes and hominids

Madagascar

When did they live?

Activity

•Complete the ‘SKULLS’ activity on the laptops: