Q: A population of flowering plants has three alleles for petal color: $$B_1$$, $$B_2$$, and $$B_3. If $$the frequency of $$B_1 is 0.25$$, $$B_2 is 0.46$$, and $$B_3 is 0.29$$, what is the expected frequency of the $$B_1B_2$$ genotype under Hardy-Weinberg equilibrium?

$$2 \times 0.25 \times 0.46 = 0.23$$

Question 1

Which of the following is NOT a requirement for natural selection to occur in a population, according to Darwin's postulates?

Accepted Answer

All individuals must have equal reproductive success.

Question 2

A population of flowering plants has three alleles for petal color: $$B_1$$, $$B_2$$, and $$B_3. If $$the frequency of $$B_1 is 0.25$$, $$B_2 is 0.46$$, and $$B_3 is 0.29$$, what is the expected frequency of the $$B_1B_2$$ genotype under Hardy-Weinberg equilibrium?

Accepted Answer

$$2 	imes 0.25 	imes 0.46 = 0.23$$

Question 3

Which scenario best illustrates disruptive selection?

Accepted Answer

A population of mice where both very light and very dark fur colors have higher fitness than medium fur color.

Question 4

In a population of flowers, blue flowers are 80% likely to be eaten by a newly introduced herbivore, while pink and white flowers are only 25% likely to be eaten. Over several generations, what is the most likely outcome for allele frequencies?

Accepted Answer

Alleles for blue flowers will decrease in frequency, while alleles for pink and white flowers will increase.

Question 5

Which of the following statements about natural selection is FALSE?

Accepted Answer

Natural selection always leads to perfection in organisms.

Question 6

A population is in Hardy-Weinberg equilibrium. Which of the following would violate this equilibrium and lead to evolution?

Accepted Answer

Natural selection acts on the trait.

Question 7

Which type of selection is most likely to maintain the average phenotype and reduce variation in a population?

Accepted Answer

Stabilizing selection

Question 8

In the context of sexual selection, what is the Bateman-Trivers hypothesis?

Accepted Answer

Females invest more in offspring and are choosier about mates, while males compete for access to females.

Question 9

Which of the following is an example of intersexual selection?

Accepted Answer

Female birds choosing males with the brightest beaks.

Question 10

If a population of moths in a polluted area shifts from mostly light-colored individuals to mostly dark-colored individuals over time, which type of selection is occurring?

Accepted Answer

Directional selection

Question 11

Which misconception about evolution is addressed by the statement: 'Evolution is not goal-oriented and does not always lead to more complex or 'better' organisms'?

Accepted Answer

Evolution is progressive and always leads to perfection.

Question 12

A trade-off in natural selection is best illustrated by which example?

Accepted Answer

Dung beetles can produce many small brood balls or few large brood balls, but not both.

Question 13

Which equation represents the expected genotype frequency for a heterozygote in a population with two alleles, $$p$$ and $$q$$, under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq$$

Question 14

Which of the following is TRUE about sexual dimorphism?

Accepted Answer

It refers to differences in traits between males and females of the same species, often due to sexual selection.

Question 15

Which mechanism of evolution is the only one that consistently leads to adaptive evolution?

Accepted Answer

Natural selection

Question 16

In a population of frogs, males with the loudest calls attract more mates, but also attract more predators. What evolutionary concept does this scenario illustrate?

Accepted Answer

Trade-off between reproductive success and survival

Question 17

Which of the following best describes the process of evolution by natural selection?

Accepted Answer

Change in allele frequencies in a population over generations due to differential survival and reproduction of individuals with certain phenotypes.

Question 18

Which type of selection is most likely to result in two distinct phenotypes in a population, with few individuals showing intermediate traits?

Accepted Answer

Disruptive selection

Question 19

If a population of birds experiences selection favoring intermediate-sized galls due to predation by both wasps (on small galls) and birds (on large galls), which type of selection is occurring?

Accepted Answer

Stabilizing selection

Question 20

Which of the following is a plausible consequence of non-random mating in a population?

Accepted Answer

Genotype frequencies will change, but allele frequencies may remain the same.

Mechanisms of Evolution: Natural Selection and Population Genetics

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