Chapter 17, Problem 12STP

Summary Introduction

To assess:

The advantages of bipedalism

Introduction:

The hominins include humans and all their extinct relatives. Hominins are bipedal. When they became bipedal, they developed a fully upright stance, shortened arms, restructured hip bones and foot bones and a change in position of head on spinal cord. These evolutionary changes led to bipedalism.

Answer to Problem 12STP

The advantages of bipedalism include:

• Long distance travel was more efficient than walking on four limbs.
• Area of body exposed to sunlight reduced and area exposed to cooling winds increased.
• Could carry objects more efficiently and use hands for other purposes
• Helped hominins reach fruits on low branches easily.

Explanation of Solution

There are many advantages of bipedalism. When hominins evolved the landscape of Africa was changing and bipedalism was an adaptation to the new savanna environment. Food resources were sparse and far apart. The hominins had to travel long distances. By walking upright they could travel long distances more efficiently.

The area of body exposed to sunlight also reduced due to walking upright and subsequently the area exposed to cooling winds increased.

Bipedal hominins were better able to carry objects and use their hands for other purposes.

The upright position helped hominins reach fruits on low branches easily as they travelled from tree to tree.