Week 11 - Bipedalism and Hominins Before 1 million years ago
After reading Chapters 8 and 9 in your textbook, watching the video "Becoming Human: First Steps"
answer the following questions.
https://www.pbs.org/wgbh/nova/video/becoming-human-part-1/
1.
What are four characteristics that you would look for in a fossil hominin to determine that it was a
biped? Describe one theory that attempts to explain why hominins became bipedal and if you
think the theory is a valid explanation. (150 words)
The four characteristics sought out in determining if a fossil hominin is biped is: the shift of the
foramen magnum (an area between the skull and neck) to then be more so underneath the skull
forcing this sort of balance onto the head,
the lower limbs of the legs are seen to be stretched in
size while the femur is also positioned more inward that then cause the legs to be placed right
below the body and finally the big toe is significantly large but now aligned with the other toes.
One theory that describes the bipedalism of hominins is the theory on how this form of
locomotion saves us energy as discussed in the video. I do in fact think this theory seems to make
sense in why bipedalism has occurred within hominins. The chimp is fueled by and also uses
enormous amounts of energy to get by its days. The chimp can choose to walk on all fours are just
their lower limbs, but for both cases they exhibit a poorly designed anatomy which is difficult for
them to withstand gravity and stay on those two limbs for long. Therefore, the small anatomical
difference of bipedalism in hominins allows for a more energy saving difference that can then be
used at almost peak efficiency.
2.
What hominin category has your group been assigned for the in-class "Hominin Fact Sheet"
group activity? Give a brief description of that hominin. (50 words)
My group has been given the hominin category of the Earliest Hominins:
Sahelanthropus, Orrorin
and
Ardipithecus.
By being the earliest in history, these hominins are often dubbed as “possible
hominins” with the study of their traits. The
Sahelanthropus’s are shown to have a more “in
between” foramen magnum in the sense that that shares the characteristics of a bipedal hominin
but also a quadrupedal ape. The Orrorin’s cranial remains have depicted more of a bipedal
locomotion which is the same for the Ardipithecus who is considered to be well adapted to
bipedalism from examining its remains.
