Human Evolution Biological Differences Flashcards
Sagittal crest
Apes have a small one Humans have none
Site for attachment of large jaw muscles. Runs along the top of the head
Zygomatic arch
Apes have large Humans have small.
Where jaw muscles are, smaller in humans due to softer food with higher nutrition content
Brow ridge
Large in apes smaller in humans
Larger in apes as reinforces the weaker bones to cope with the pressure of powerful chewing
Arm:Leg ratio
Longer arms in comparison to legs in apes due to being useful for brachiation
Humans have shorter arms as they do not partake in brachiation
Toes
Apes have long curved finger like toes which are useful in brachiation
Humans have shorter toes with incline big toe as they do not use brachiation
Rib cage
Apes have a curved rib cage Humans have flat
Humans is flatter as it makes the centre of gravity closer to the spine
Valgus angle
The inward angle of hips in humans. Brings the weight bearing point of the knee to move under the body closer to the centre of gravity.
Apes have parallel femur
Foramen magnum
The hole in the skull where the spine attaches to the head.
Apes it is at the back of the skull to allow for quadrapedalism
Humans it is at the base of the skull to aid bipedalism as it places it over the centre of gravity
Pelvis
Apes have a straight pelvis and humans have bowl shaped
Bowl shaped pelvis supports the valgus angle in shifting the centre of gravity
Big toe
Apes have angled and Humans have straight
Straight big toes allows for more linear movement
Flat vs arched feet
Apes have flat humans have arched
Arch absorbs shock and allows for “spring”
Spine
Apes have arched spine humans have s shaped
S shaped brings the body’s centre of mass directly over the feet allowing for upright stance and motion
Teeth/mouth
Apes have U shaped dental arch with big teeth
Humans have V shaped dental arch with small teeth
Humans due to change in diet to softer and more nutritional foods
