Human Evolution P.1

foramen magnum

positioned further under skull so that the head is balanced better on the spine

spine curves

thoracic is backwards, lumbar forwards, keeps trunk centered above the pelvis

pelvis

shaped more in form of basin, shorter and squatter

why is the pelvis shaped the way it is?

supports internal organs and stabilizes weight transmission

lower limbs

elongated, longer than arms

femur

angled inwards, keeping the legs more directly under the body

what is the angle on the femur called

valgus angle

big toe

enlarged and brought in line with the other toes

what does the big toe create

distinct longitudinal arch on feet

what is CP3

built in sharpener for canines, bottom premolars rub against the canine

do hominins have CP3

they have evidence of CP3 but it does not work

what are some benefits of bipedalism

energy efficient, can carry tools and infants, can travel between trees or see over grass, provisioning

how to recognize a hominin in the fossil record

jaw shape, bipedalism, no Cp3

pre-australopithecines, 7mya-4mya

all found in Africa, closest to the great apes will have closest traits to great apes

what is the earliest pre-australophithecine

sahelanthropus tchadensis

what is the second earliest pre-australopithecine

orrorin tugenesis

what is the third earliest pre-australopithecine

ardipethicus kadabba and ramidus

sahelanthropus tchadensis facts

oldest hominin, foramen magnum, large browridge, small brain size, no diastema

orrorin tugensis

has large, more ape-like canine, fragmentary cranial and post cranial remains

ardipithecus kadabba

has curvature finger bones, lived in wooded environment

ardipithecus ramidus

face is not as projecting as a chimp, but more projecting than later hominin, tree climber and bipedal

primitive

traits passed down by ancestors

derived

new traits in group

austrolopithecus group

only found in Africa, range in size from 64-100 lbs, moderate prognathism. mixture of primitive and derived traits

olduvai gorge

oldest archaeological site, used to have water

australopithecus anamensis

U shaped jaw, found in Kenya, not a lot of fossils but important parts

australopithecus afarensis

morphology of fossil is female (Lucy), 425 cc brain size

australopithecus garhi

primitive, small brain, large canines, sagittal crest, maybe early tool use

australopithecus africanus

only found in South Africa, 3.5-2.0 mya