EVIDENCE OF COMMON ANCESTORS
main sources of evidence:
1. Fossil evidence
2. Genetic evidence
3. Cultural evidence (archaeological)
(1) Fossil Evidence
bipedalism / brain size / teeth / prognathism / palate shape / cranial and brow ridges
, Bipedalism Advantages of bipedalism:
live in a greater variety of areas (forests, savannah)
see danger from predators
gather food / make and use tools
reduce the risk of overheating
Disadvantages of bipedalism:
backbone no longer acts like a cantilever bridge between the hind and forelimbs
it is put under a lot of stress
removes the shock-absorber function of the shoulder blade
reshaping the pelvis narrows the birth canal
How to identify a bipedal fossil:
foramen magnum is positioned further forward
shorter, broader pelvis -- efficient weight distribution
S-shaped spine -- acts like a spring to maintain the upright posture
main sources of evidence:
1. Fossil evidence
2. Genetic evidence
3. Cultural evidence (archaeological)
(1) Fossil Evidence
bipedalism / brain size / teeth / prognathism / palate shape / cranial and brow ridges
, Bipedalism Advantages of bipedalism:
live in a greater variety of areas (forests, savannah)
see danger from predators
gather food / make and use tools
reduce the risk of overheating
Disadvantages of bipedalism:
backbone no longer acts like a cantilever bridge between the hind and forelimbs
it is put under a lot of stress
removes the shock-absorber function of the shoulder blade
reshaping the pelvis narrows the birth canal
How to identify a bipedal fossil:
foramen magnum is positioned further forward
shorter, broader pelvis -- efficient weight distribution
S-shaped spine -- acts like a spring to maintain the upright posture
