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Climate and Human Evolution; the last
4.6 billion years
By Kristin Hepper
Time gone by…
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
Sturtian Ice Age- 750 million years ago
Varangian Ice Age- 600 million years ago
Muir Glacier at Glacier Bay, 1971
Phanerozoic Eon
Archaean Era, Proterozoic Era, Phanerozoic Eon
544 million years ago to the present Divided into three Eras
Cenozoic 65 million years ago to the present
Mesozoic 248 to 65 million years ago
Paleozoic 544 to 248 million years ago
Pangaea- one supercontinent300-200 million years ago
Laurasia and Gondwanaland
Triassic- 200 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…
To the Pliocene 5-1.8 million years ago
What is going on? Antarctic ice sheet melts back significantly Climate is oscillating Tethy’s Seaway
What about our ancestors?
Earliest known hominoid- Proconsul africanus 16 mya East Africa
Divergence from the great
ape lineage 5 mya Timing estimated from
molecular clock
Ardipithecus ramidus (Pliocene)
From Aramis in Ethiopia
5.5-4.4 mya
Primitive dentition
Oldest taphonomically determined example of australopithecines
Maybe the missing link???
Ardipithecus ramidus: upper right molar
Australopithecus anamensis (Pliocene)
Lake Turkana, Kenya 4 mya More adaptations to
bipedality
Australopithecus afarensis (Pliocene) Known to the world
as “Lucy” 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
Brain size- 415 cc’s
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 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
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 1200-1250 cc’s
Out of Africa
Remember…
Out of Africa- what was happening in Africa in the Plio-Pleistocene
Habitats were unstable 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
Human Neanderthal
Brain Size1300 cc’s
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
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
Long limbs