Question

which of the following is not an anatomical feature in hominids related to bipedalism?

a)a larger brain case to accomodate a larger brain

b)a big toe aligned so that it is in line with the other toes

c) the forward responsitioning of the foremen magnum directly underneath the cranium

d) the modification of the pelvis into a basin-like shape

Answer 1

Answer - a. A larger brain case to accomodate larger brain.

Explanation :

Bipedalism - is evolution to walk on two feet. During evolution body adapted certain changes to be able to stand and walk on two hind limb.

Features of Bipedalism -

1) bicondylar angle or valgus knee
2) inferiorly placed foramen magnum
3) reduced or nonopposable big toe
4) high arch foot
5) posterior orientation of the anterior portion of the iliac blade i.e. Basin shaped pelvis
6) large femoral head
7) long femoral neck
8) slightly big and anteroposteriorly elongated femur condyles

Bipedalism evolced well before enlarged huamn brain. Large size braincase to accomodate large brain is evolution as human, not necessary for Bipedalism.

Hence, answer is A.