Human Evolution: Skull Gizmo Study Set

Foramen Magnum

A large opening at the base of the skull through which the spinal cord connects to the brain.

Summarize how hominins changed as they evolved.

As hominins evolved, their posture became more upright over time. Probably the first bipedal hominins' still spent some time living in trees, but progressive hominin species slowly moved out of trees, using walking to get around.As hominin posture became more erect, their brain size increased, leading to an increase in intelligence and tool use. The tool use led to an increase in the amount of processing the food underwent. As food processing increased, the mouth and tooth size decreased, leading to the flattened features that humans now possess.

How did the increase in cranial capacity affect the use of tools?

As the size of the brain increased, the use of tools became more common.

What came first: bipedalism or large brains?

Bipedalism came before large brains. Measurements show that the foramen magnum moved forward towards the middle of the skull, in order to accomodate a bipedal posture, well before the increase in cranial capacity.

This happened to the size of the brain as hominins evolved

Brain size increased

What is cranial capacity a good indicator of?

Cranial capacity is a good indicator of intelligence.

Hominin

Humans and human-like ancestors, such as homo habilis and homo erectus.

Hominid

Humans, Chimpanzees, and other great apes, such as orangutans and gorillas.

What is the relationship between the evolution of bipedalism, the increase in cranial capacity, and the decrease in tooth and mouth size in hominins?

The evolution of bipedalism freed the hands for other uses. The increase in cranial capacity implies a larger brain, which would lead to an increase in intelligence. Both are linked to the development of sophisticated stone tools and the use of fire. Wth stone tools to cut up food, and fire to cook it with, large and powerful teeth and jaws became unnecessary.

What happened to the position of the foramen magnum as hominins evolved into modern humans?

The foramen magnum moved forward towards the middle of the skull, in order to accomodate a bipedal posture.

Cranium

The portion of the skull that encloses the brain

Cranial capacity

The size of the space occupied by the brain.

How did the increase in tool use affect the size of the jaws and teeth as hominins evolved?

The use of tools made large protruding jaws with giant teeth unnecessary, so jaws and teeth slowly evolved to be smaller

Bipedal

Walking on two legs