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hominids

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all modern and extinct great apes including gorillas, chimps, orangutans and humans

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hominins

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any species of early human that is more closely related to humans than chimpanzees, including modern humans themselves

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Carol Ward

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professor of anatomy at the University of Missouri in Columbia

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worked in the field in Kanapoi, Kenya

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at the southern end of Lake Turkana

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examined the question what is it about bones in the skeleton that tell us about how ancient creatures moved and lived

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Micocene apes

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23 to 5 million years ago

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arboreal orthogrady

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using an upright posture to move in the trees

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not specialized like African apes

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they could stand upright

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there used to be hundreds of great apes

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Ardipithecus ramidus

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4.4 million years ago

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an anatomy not much like Australopithecus afarensis

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walked upright some of the time

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but not committed to terrestrial bipedality like Australopithecus was

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Australopithecus

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the most important species of early hominins

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the first evidence of bipedal locomotion

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what did adaption favor them to do

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what did selection train them to do

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Australopithecus anamensis

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4.2 to 3.9 million years ago

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regular bipedal walking

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East Africa

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follows Ardipithecus

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probably walked on two feet

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we don't know if it

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had a grasping big toe

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had a big brain or small brain

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have some jaw bones

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getting better at chewing, using their front teeth less

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something changing in their diet

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don't know their habitat

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there one thing you can be sure about any new fossil, it's not going to be what you expected

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one thing we understand when looking at bones is how ligaments were attached

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Australopithecus afarensis

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3.85 and 2.95 million years ago

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Lucy's species

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remains from over 300 individuals

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old and young

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male and female

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we know most about this species

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they walked on two feet

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they lost the grasping big toe

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we are the only primates that don't have a grasping big toe

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that's a really useful thing to have if you are climbing in the trees

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this tells us that walking upright on two feet was so important, for our survival and reproductive success, that they lost this incredibly useful ability of climbing trees

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it involved a sacrifice of giving up the grasping toe

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many theories

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being able to stand up to see over the tall grass

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thermal regulation

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display among individuals

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to me, the only reason you wouldn't use your hands to walk with was maybe you had something in them

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carrying objects, food, tools

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the hand

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very human-like

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but the fingers are not very human-like

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very adapted to climbing, has muscularity

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the shift to Homo

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you have to look at a fossil animal as if it never left any descendants

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we look at Lucy and see that

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her fingers were curved and longer than ours

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her wrist bones were not quite like our are

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we conclude she was not as good at being human-like

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so they must have been doing something else

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they had the flexor pollicis longus in the forearm as humans do which allowed them to oppose the thumb powerfully

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special to humans

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they have grasping hands unlike the ape

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homo sapiens and afarensis have retained climbing ability

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you have to ask where these changes came from

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perhaps throwing became important

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using tools