Question

question 7 (multiple choice worth 4 points)
(05.02 mc)
a gene that controls an observable trait in birds has three different alleles. which of the following best describes how gene flow would affect the genetic makeup of this population?

• allele frequencies would shift until the population has only one allele.
• birds would choose to express the allele that provides them with the greatest survival advantage.
• the allele that provides the greatest survival advantage would increase, while the other two allele frequencies would decrease.
• the bird population would have new alleles introduced into the gene pool, increasing genetic variation.

question 8 (multiple choice worth 4 points)
(05.03 mc)
in what way did an increased skull and brain size affect hominid evolution from early ancestors to modern humans?

• they became less reliant on vision and more reliant on all of their senses.
• they became less reliant on tools and less reliant on social interactions.
• the larger brain size increased, causing their overall body size to decrease.
• the gestation and infant care period increased to allow the brain to develop.

Explanation:

Question 7

Gene flow involves the transfer of genetic material (alleles) between populations. When gene flow occurs, new alleles can be introduced into a population's gene pool, which increases genetic variation.

• The first option is incorrect because gene flow doesn't typically lead to a population having only one allele (that's more related to genetic drift or strong selection in some cases, not gene flow).
• The second option is wrong as organisms don't "choose" to express alleles; expression is based on genetics and environment, not a conscious choice.
• The third option describes natural selection (advantageous allele increasing), not gene flow.
• The fourth option correctly describes gene flow: introducing new alleles and increasing genetic variation.

An increased skull and brain size in hominids required more time for brain development. The gestation period (time in the womb) and infant care period (after birth) increased to allow the complex brain to develop properly.

• The first option is incorrect: hominids became more reliant on vision (e.g., for tool use, social interactions) and complex cognitive functions, not less reliant on vision.
• The second option is wrong: larger brains led to more tool use and more complex social interactions, not less.
• The third option is incorrect: there's no direct link between brain size increase and overall body size decrease; body size has varied in hominid evolution for other reasons.
• The fourth option is correct: the longer gestation and infant care period supported brain development.

Answer:

D. The bird population would have new alleles introduced into the gene pool, increasing genetic variation.

Question 8