Climate and Human
Evolution; the last
4.6 billion years
By Kristin Hepper
Time gone by…
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Earth is 4.5 billion years old

Archaean Era 3800 to 2500 million
years ago

Proterozoic Era 2500 to 544 million
years ago
Stromatolites
Ice Ages

Huronian Ice Age- 2.3 billion years ago

Gnejso Ice Age- 950 million years ago
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Sturtian Ice Age- 750 million years ago
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Varangian Ice Age- 600 million years ago
Muir Glacier at Glacier Bay, 1971
Phanerozoic Eon
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Archaean Era, Proterozoic Era, Phanerozoic
Eon
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544 million years ago to the present
Divided into three Eras
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Cenozoic 65 million years ago to the present
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Mesozoic 248 to 65 million years ago

Paleozoic 544 to 248 million years ago
Pangaea- one supercontinent
300-200 million years ago
Laurasia and Gondwanaland
Triassic200 mya
Say Goodbye to Pangaea…
Jurassic
Cretaceous
But, they are still moving….
The question is…where are they going?
Just one hypothesis…
Now that we are at the present,
let’s jump back 5 million years…
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To the Pliocene
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5-1.8 million years ago
What is going on?

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Antarctic ice sheet melts back significantly
Climate is oscillating
Tethy’s Seaway
What about our ancestors?

Earliest known hominoid- Proconsul
africanus

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16 mya
East Africa
Divergence from the great
ape lineage

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5 mya
Timing estimated from
molecular clock
Ardipithecus ramidus (Pliocene)

From Aramis in Ethiopia
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5.5-4.4 mya

Primitive dentition

Oldest taphonomically determined example of
australopithecines
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Maybe the missing link???
Ardipithecus ramidus: upper right molar
Australopithecus
anamensis
(Pliocene)
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Lake Turkana, Kenya
4 mya
More adaptations to
bipedality
Australopithecus
afarensis (Pliocene)

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
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Known to the world
as “Lucy”
 Brain size415 cc’s
Hadar, Ethiopia
Varied from 1-1.7 m
in height and 25-50
kg in weight
Ate fruits and nuts
and some meat while
living in a wooded
environment
Laetoli Footprints- Tanzania
Preserved in volcanic tuff
erupted out of Mt. Sadiman to the
east, which is dated back to 3.7
mya.
75 ft long
69 total prints
Australopithecus africanus
(Pliocene) The Taung Baby

Material comes from all over Africa

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Sterkfontein, Makapansgat, and Taung
3-2.4 mya
Has more derived characteristics
Lived in a more open environment and
maybe used underground resources such
as roots
Brain size- 450 cc’s
Pleistocene- 2 mya-10,000 ya

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Biotas were similar to modern
ones
Characterized by distinctive
large animals
Global oscillations of ice sheets
Global oscillations of
productivity
Humans…here we come!!!
Glacial maximum
Homo habilis (Pleistocene)

First appearance of
Homo 2.4 mya

Olduvai Gorge, Tanzania

Brain size- 590-710 cc’s

Specimens show high
variability of traits

Stone tools
Homo ergaster (Pleistocene)

Lake Turkana, Kenya; Olduvai
Gorge, northern Tanzania

1.8 mya

Big brain- 900 cc’s

Very human-like body

Associated with tools
Homo ergaster
600,000 to 400,000 years ago

Homo heidelbergensis

Around 600,000 ya
hominids start

Showing some
differences from H.
ergaster

Had larger brains 12001250 cc’s

Out of Africa
Remember…

Out of Africa- what was happening in
Africa in the Plio-Pleistocene

Habitats were unstable

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Grasslands were expanding and contracting
Climate is oscillating
Homo neanderthalensis


Neander Valley,
Germany
200,000 to 35,000 ya in
Europe and W. Asia

Tools

Burial

Had thick brow ridges
 Brain Size1300 cc’s
Human
Neanderthal
Homo sapiens

Anatomically modern Homo

Africa: 100,000 to 90,000 ya

50-45,000 ya evidence of culture

Reach Australia between 50,000 and
35,000 ya
Homo sapiens

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35,000 ya adapted to cold Siberia and
Alaska
14,000 ya crossed the land bridge into the
Americas
Islands of Pacific were settled around
3,000 ya
New Zealand was the last 1200 A.D.
Features of Homo sapiens

Big brains 1500 cc’s

High foreheads

Face is flat and pushed in

Small brow ridge
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Long limbs