Humans as Bipedal Primates Flashcards
What does arboreal mean?
Acting/living in trees
What is the Broca’s region?
A region of the brain concerned with the production of speech, located in the cortex of the dominant frontal lobe
What is the brow ridge?
A bony ridge located above the eye sockets if all primates.
What is the cranium?
The part of the skull that encloses the brain
What is formen magnum?
The large opening at the base of the skull through which the spinal cord passes
What is the nuchal crest?
A bony ridge at back of the skull. It is where the neck muscles and ligaments are attached in order to support the head.
What is the mandible?
The lower jaw or jawbone
What is an obligate biped?
Adapted for walking only on two legs, with no ability to walk on four.
What is an opposable thumb?
A thumb that can be placed opposite the fingers of the same hand
What is a prognathic jaw?
A “forward jaw”. Describes the degree to which the maxilla and mandible (the muzzle) extend forward of the face.
What is a saggital crest?
A bony ridge on the top of the skull to which the jaw muscles are attached.
What a valgus angle?
The angle the femur makes relative to the knee. Close to 90 degrees in non-human apes, less in bipedal humans.
What is the wernicke’s area?
A region of the brain concerned with the comprehension of language, located in the cortex of the dominant temporal lobe.
What is a zygomatic arch?
The bony arch at the outer border of the eye socket, formed by the joining of the cheekbone and the zygomatic process of the temporal lobe.
What is bipedalism?
Having two feet and using two feet for locomotion.
What is obligate bipedalism?
Walking only on two legs with a reduced ability to walk on all four.
The main trait that defines the hominin lineage and separates us from the rest of the apes.
Why do humans have a barrel shaped ribcage?
Allows the arms to swing freely from side to side to assist with balance when walking upright.
How have human feet evolved?
Toes are straighter and shorter. The big toe (hallux) is larger and more robust, aligned with the other toes for propulsion. Well developed arches. Robust heel that can absorb forces encountered during heel strike.
What do chimpanzee feet look like?
Opposable hallux used for grasping branches. Foot lacks arches and the entire surface of the foot makes contact with flat ground.
Human Foramen Magnum and Nuchal Crest
Foramen Magnum is nearer the centre of the skull and opens directly downward.
Humans have a cranium that rests on top of the vertebral column so the position of the Foramen magnum helps to balance the mass of the head above the spine.
Humans don’t have a large nuchal crest at the back of the cranium like the apeas.
Ape Foramen Magnum
Foramen magnum lies towards the back of the skull.
Human spine
S shaped spine brings the body’s centre of gravity directly over the middle of the pelvis and allows rhe spine to flex and absorb forces during locomotion.
Chimpanzee spine
Bow shaped supports abdomen and helps to absorb forces generated by quadrupedal locomotion.
Human pelvis
Shorter, broader, bowl shaped. Supports the gut when upright.