There are 3 major lineages of hominids that lived between 2.0 and 1.2 million years
ago (mya) that co-existed included; Paranthropus, Australopiths and Homo Erectus
(Jurmain, p. 215). Large gaps of findings remain between the hominids, thus making
it a debatable to categorize skeletal findings of a hominine. Analyzing the four
groups helped categorize the hominin; Physical characteristics: such as, body,
cranial shape, browridges, brain sizes; Locomotion, skeletal sizes for purposes of
movement, climbing, walking, grabbing; Dentition, teeth variables and enamel caps
and relation to dietary; along with tool making behaviors in relation to critical
thinking and skills. In contract, smaller characteristic variations remain, like the
“Black Skull”, which fall between two hominids, and given a new species name of
Paranthropus aethiopicuslarge.
The three ancestry categories of hominids shared habitats that included
living in trees (arboreal) with rough and high fiber plant diets (Jurmain, Ch. 8
lecture). Australopithecus afarensis was the first hominid to have walked more
distinctly related to humans (Homo sapiens) in an upright position. “Lucy”, an A.
afarensis hominin, is the longest-lived and known discoveries (3.2 mya in East
Africa) that can be traced as the origin of modern “human”. Studying the locomotion
and posture of multiple A. afarensis hominine assisted with evolutionary connection
to earlier hominids and closer relating to that of its successor hominin Homo
erectus (erectus meaning: “up right human”). “Lucy” (A. afarensis) knee and spin
showed that she spent more time walking on two legs (Walker et al., 2006)
(Jermain, p. 217). A. afarensis bipedal movement may have hindered their climbing
skills but it did not mean they did not live in trees (Jermain, p. 220). The most
noticeable difference between modern humans, and A. afarensis is the skull. A.
afarensis and Homo erectus cranial capacity (909 cc) is more closely related to
humans than previous hominids; however, A. afarensis (404 – 515 cc) was nearly
35% smaller than humans. A. afarensis is closely related to the modern chimpanzee
based on cranial size and rapid growth from birth to adulthood. (Jurmain, ch. 9)
Homo erectus and A. afarensis shared shorter fingers/toes and larger body