Biological Anthropology - 4.3

Australopithecus afarensis

-3.6 - 3.0 mya -Ethiopia -ancestor was the A. anamensis -ancestor to the A. africanus from South Africa and A. ghardi (made and use the first stone tools) -skeleton and limb bones indicate that the form of walking was likely similar to modern humans' -was a efficient, habitual biped that spent most of its time on the ground -nondivergent big toe

Australopithecus anamensis

-4 mya -Lake Turkana, Kenya -oldest australophiethcine, ancestor of the A. afarensis -Awash River Valley, Ethiopia -large canines, parallel roots rows in the upper jaw,

Ardipithecus ramidus

-4.4 - 5.8 mya -Awash River Valley, Ethiopia -pre-australophithecines -One of the earliest bipeds that lived in the forested portions of eastern Africa -curved phalanges, continued use of the trees -femur and pelvis shape indicate this

Ardipithecus kadabba

-5.8-5.6 MYA -Awash River Valley, Ethiopia -pre-australophithecines -known mainly from teeth that shows the hominins' canines wore from the tips (not the sides) but still had some honing -intermediate honing -curved phalanges, continued use of the trees -femur and pelvis indicate capable of bipedalism

orrorin Tugenenesis

-6 MYA -Tugen Hills, Kenya (east africa) -pre-australophithecines -found in Kenya -curved phalanges which means they continued to use the trees -possible indication of bipedalism due to the long femoral neck

Sahelanthropus tchandensis

-7-6 mya -Chad -pre-australophithecine -oldest species, central Africa -Back of skull resembles ape, small brain, face has less protrusion (prognathism), much smaller canines, structure of skull (forum magnum) suggest bipedalism, massive brow ridge -possible bipedalism due to the located of the foramen magnum, canine was non-honing

Derived Traits

-Newly evolved features, such as feathers, that do not appear in the fossils of common ancestors -Those that only developed among a particular group of species, and were not present in their ancestors

Convergent Evolution

-Process by which unrelated organisms independently evolve similarities when adapting to similar environments -Ex: Shark - Fish, Ichtyosaur - Reptile, Dolphin - Mammal - all similar structure for swimming, but different species

Primitive Traits

-Referring to traits inherited by a group of organisms from a remote ancestor and thus not diagnostic of groups (lineage) that diverged after the traits first appeared; also called ancestral -Ancestral traits

Pre-austrolaphithecines

-oldest hominids -likely bipeds -general traits: wear on tip of canine but have modified honing, apelike arboreal traits, small brains

Australopithecines

4-1 MYA -recent group of hominids clearly bipedal with non honing chewing -general traits: slightly larger but still small brain, small canines, large premolars, and large molars, non-honing teeth, loss of apelike arboreal traits

Sites for Pre-australophithecines

Chad, Awarsh River Valley in Ethiopia, Tugen Hills in Kenya,

Non-Honing Cane

non-honing chewing is characterized by a number of changes in dentition -canines are generally smaller and non-projecting, more blunt -no longer a diastema between the canine and the incisor -non-honing chewing changes the pattern of wear on the teeth -instead of wear on the back of the canines, hominids show wear on the tips of the canines and