Effect of Environment on Evolution (19)

Question 1

What allowed scientists to determine environment of ancestral hominins

Answer 1

Using geological and chemical info + info on types of fossilized plants and animals found

Question 2

Where, after split from early chimps, did early hominins thought to have lived

Answer 2

woodland or forest environment

Question 3

explain features of early hominid respect to living in trees

Answer 3

o ape-like, w/ arms + hands that retained features suited to living in trees

Question 4

How were early humans similar to orangutans

Answer 4

• Frequently move over small springy branched bipedal manner using their arms for balance

Question 5

what did locomotion of early humans allow in environment

Answer 5

This kind of locomotion (upright) used where there were gaps in forest canopy + early hominins needed to travel across open ground

Question 6

What environmental change occurred 506 million yeas ago

Answer 6

temp fall= forest areas diminish in size // open areas

Question 7

What did the change in environment produce in terms of natural selection

Answer 7

♣ In such conditions= many arboreal animals not survive
♣ However same features that enabled apes to live in trees allowed limited bipedalism on ground
• As forest thinned + trees= further apart= more open spaces
• In this situation, natural selection favored apes that were better at bipedal walking

Question 8

What did natural selection favour

Answer 8

favored individuals with a more erect stance who were able to move bipedally across grass lands

Question 9

What are 5 advantages of erect posture

Answer 9

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Increased range in vision for detecting prey and predators at a greater distance
Increased size, deterring predators
Hands free for carrying food, and perhaps tool use
Higher reach when picking fruit from trees
Improved cooling of the body

Question 10

Why is cooling of body feature of bipedalism

Answer 10

• body vertical (not horizontal or quadrupedalism) the sun strikes a smaller fraction of it, helping avoid overheating
• In addition, upper body is above ground where there is more wind to help cool the body and where air temperatures may be marginally lower than at ground level