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Human Evolution: an
overview
Dr Jeremy Pritchard
o
Hominoid: Great apes and humans
o
Hominid: Closer to us than gorillas and chimps
You
Dad
Cuz
Mum
Aunt
Uncle
o
Humans did not evolve from Apes
o
You are descended from your mother and father
o
You are related to your aunt and cousin
Common
ancestor
Contemporary
animals
Contemporary
animals
Fossil
s
Organisms with
common features are
likely to have a more
recent common
ancestor.
Locomotion
Brachiation:
o Grip
o Stereo vision
Humerus
Femur
1. Chimpanzee
2. Australopithecus africanus
3. Homo erectus
4. Homo sapiens
Brain size
Primate Characteristics/Trends
o
Brains larger than other animals
Brains larger than other animals in relation to body size
Log brain weight (g)
• Brains larger than other animals
Log body weight (g)
Information from the skeleton
• sex
• age
• stature
• race/species
• pathological conditions
• skeletal trauma
Trauma
Trauma
Trauma
Trauma
Proconsul
Sahelanthropus tchadensis
• close to the common ancestor of humans and
chimpanzees @ 7 million years
Australopithecus afarensis
Lucy, discovered in Ethiopia in 1974.
Australopithecus
Southern
Ape
africanus
of
Africa
Don’t run before you can walk
Homo habilis (ca. 2.5-1.6 mya)
Homo erectus (1.6 mya-300 kya)
2000
Brain capacity (cm 3)
Homo neanderthal
1500
Homo sapiens
Homo erectus
1000
Homo habilis
500
Australopithicus
africanus
ramapithicus
0
0
2
4
6
Fossil age (MYA)
8
10
Skull radius (cm)
Brian volume (cm3)
6
454
6.25
513
6.5
577
6.75
646
7
720
7.25
800
7.5
886
7.75
978
8
1075
8.25
1179
8.5
1290
8.75
1407
9
1531
9.25
1662
9.5
1800
9.75
1946
10
2100
10.25
2261
10.5
2431
10.75
2609
11
2795
11.25
2990
11.5
3194
Neanderthals (ca. 100-32 kya)
Neanderthals (ca. 100-32 kya)
o
o
Restricted to Europe, eastern Middle
East during Ice Age
Evolved to be cold-adapted:
–
–
–
–
Short and stocky
Large nose (for warming air)
Barrel chest (for warming air)
Long, low, thick skull but with
large Brain
Neanderthals are not our ancestors
Homo habilis
Homo erectus
Archaic Homo sapiens
Homo sapiens sapiens
Homo sapiens neandertalensis
NOT our ancestors….
Krings et al 1997 Neandertal DNA Sequences and the Origin of Modern Humans
Are we still evolving?
Microevolution: change in gene frequency - YES
Macro evolution : formation of species - NO
Are we still evolving?
• Some parts of Africa have seen an increase in the
frequency of a gene called CCR5-32
• Protects against infection with HIV-1.
• May have been selected for during bubonic plague
Human Evolution - Chimps are our closest relative
25,000 genes
25, 000 genes