Life on Earth

Evidence for human evolution

Evidence for human evolution

Chimps and gorillas are apes.

Human beings share many features with them.

Chimps and gorillas are our closest living relatives.

Evidence for human evolution

From this evidence, do you think human beings are closest to chimps or gorillas?

Feature Gorillas Human beings Chimpanzees

Chromosomes

Head hair

Calf muscle

Buttocks

Arms vs legs

Canine teeth

Thumbs

short

small

thin

shorter legs

large

long

48

shorter arms

46 48

small

long

fat

large

long short

small

thin

shorter legs

large

short

Evidence for human evolution

It’s not a trick question!

So far we haven’t found enough evidence to decide.

But there is enough evidence to say that humans and apes share the same ancestor.

human beings

chimps or gorillas?

chimps or gorillas?

Evidence for human evolution

We know that ape-like animals were living in Africa over 20 m y a.

scientists have found skulls with ape-like features

they can date the fossils

The evidence:

Evidence for human evolution

But they also have some differences.

no tail shoulder blades at the

back of the body

These early apes share some features with living apes:

Evidence for human evolution

Scientists use the evidence to work out how living apes are related to fossil apes.

fossils

gibbons

orangutangs

chimpanzees and gorillas

human beings

Evidence for human evolution

Do human beings have any closer relatives in the fossils?

chimpanzees and gorillas

?

human beings

Evidence for human evolution

Australopithecines lived in Africa 1.5 to 4 m y a.

Lucy - the most complete Australopithecine skeleton found.

So is Lucy more closely related to us or to living apes?

Evidence for human evolution

Australopithecines share some features with human beings.

eye sockets are wide and set apart

broad nose

sinus inside front of skull

jaw more like human than chimpanzee

sinus (spaces inside skull)

eye socket

broad nose

modern human A. africanus chimpanzee

Evidence for human evolution

Chimps and gorillas also have these features. But other apes don’t.

So are Australopithecines more closely related to:

(a) human beings?or(b) chimps and gorillas?

jaw more like human than chimpanzee

sinus (spaces inside skull)

eye socket

broad nose

modern human A. africanus chimpanzee

C9 Evidence for human evolution

In 1978 scientists found the evidence to answer this question.

These footprints were made in Africa by Australopithecines.

They walked on two legs.

Evidence for human evolution

So Australopithecines were more like human beings than chimps and gorillas.

chimpanzees and gorillas

australopithecines

human beings

Evidence for human evolution

But scientists think that we have even closer fossil relatives.

Habilines lived in Africa 1.6 to 2 m y a.

Fossils show that their spines were joined to the middle of their skull, so habilines walked upright.

Evidence for human evolution

We have more evidence about habilines. They had much bigger brains than Australopithecines like Lucy.

We also know that they made tools.

So the evidence tells us that habilines are more closely related to modern humans than Australopithecines.

Species Brain size (ml)

Human beings

Australopithecines

Habilines

1400

500

650

Evidence for human evolution

Habilines were probably the first animals on earth to make tools.

Tool making is a very important feature of human beings.

So scientists think habilines were the first early humans.

They are called Homo habilis.

australopithecines

habilines

human beings

Evidence for human evolution

Fossils of other early humans have also been found.

Species Brain size (ml)

Human beings

Australopithecines

Habilines

1400

500

650

Homo erectus 900

Homo erectus lived in Africa 1.5 m y a.

Evidence for human evolution

Their large brains mean that Homo erectus are more closely related to modern humans.

habilines (Homo habilis)

Homo erectus

modern humans

Scientists have also found evidence that they were able to make fire.

Evidence for human evolution

Homo erectus were also the first early humans to leave Africa.

Their skeletons have been found in Asia and Europe.

Evidence for human evolution

But Homo erectus are not quite the same as modern humans. For example, their skulls have a thick, straight brow ridge.

So scientists think that we must have at least one more recent ancestor.

Evidence for human evolution

The search goes back to Africa. We know that not all Homo erectus left when they first moved out of Africa.

Those that stayed carried on evolving into modern humans.

We know this because skulls shaped more like a modern human have been found in Africa. This one from Ethiopia is only 160,000 years old.

Evidence for human evolution

Homo sapiens fossils this old have been found in Israel.

Modern humans are called Homo sapiens.

They left Africa about 120,000 years ago.

habilines

Homo erectus

modern humans

Evidence for human evolution

By 40,000 years ago modern humans had spread across the world.

Evidence like cave paintings and tools tell us where and how they lived.

Evidence for human evolution

These modern humans were hunters and farmers.

The symbols in their paintings tell us that they had language.

They also had ceremonies like burials.

Evidence for human evolution

Summary: Different groups of humans evolved from a common ancestor. All but one of these groups died out. Only Homo sapiens (modern humans) survived. Modern humans evolved in Africa.

modern humans

early humans

Australopithecines

living apes, like chimps and gorillas