Q: If the frequency of allele A ($$p) in a $$population is 0.7 and the frequency of allele a ($$q) is 0.3$$, what is the expected frequency of heterozygotes ($$2pq) $$under Hardy-Weinberg equilibrium?

$$2 \times 0.7 \times 0.3 = 0.42$$

Question 1

Which of the following best describes the concept of 'descent with modification' as proposed by Darwin?

Accepted Answer

It is the process by which species change over generations, with new traits arising and being passed down, leading to both similarities and differences among species.

Question 2

Which of the following is NOT a requirement for evolution by natural selection to occur in a population?

Accepted Answer

Unlimited resources for all individuals

Question 3

A population of beetles has two color morphs: green and brown. Birds preferentially eat green beetles. Over several generations, the frequency of brown beetles increases. Which type of selection is this an example of?

Accepted Answer

Directional selection

Question 4

Which equation is used to calculate the expected genotype frequencies in a population under Hardy-Weinberg equilibrium?

Accepted Answer

$$p^2 + 2pq$$ + $$q^2 = 1$

Question 5

Which of the following is an example of a postzygotic reproductive isolating mechanism?

Accepted Answer

Hybrid sterility

Question 6

A small group of lizards is blown by a storm to a new island, where they establish a new population. Over time, this population has different allele frequencies than the original population. Which evolutionary mechanism is most likely responsible for this change?

Accepted Answer

Genetic drift (founder effect)

Question 7

Which of the following statements about mutations is correct?

Accepted Answer

Mutations are the ultimate source of genetic variation in populations.

Question 8

Which of the following best explains why natural selection is not the only mechanism of evolution?

Accepted Answer

Other mechanisms such as genetic drift, gene flow, and mutation can also change allele frequencies in populations, sometimes independently of fitness.

Question 9

Which of the following is a real-world example of convergent evolution?

Accepted Answer

The development of wings in bats and birds, which evolved independently for flight.

Question 10

Which of the following best describes adaptive radiation?

Accepted Answer

The rapid evolution of many diverse species from a common ancestor, often following the colonization of new habitats.

Question 11

A scientist is studying two populations of frogs that live in adjacent habitats but rarely interbreed due to differences in their mating calls. What type of reproductive isolation is this?

Accepted Answer

Behavioral isolation

Question 12

Which of the following is a limitation of the biological species concept?

Accepted Answer

It cannot be applied to asexual organisms or fossils.

Question 13

Which of the following best describes the process of allopatric speciation?

Accepted Answer

Speciation that occurs when populations are separated by a physical barrier, leading to genetic divergence.

Question 14

Which of the following is an example of a prezygotic isolating mechanism?

Accepted Answer

Temporal isolation

Question 15

If the frequency of allele A ($$p) in a $$population is 0.7 and the frequency of allele a ($$q) is 0.3$$, what is the expected frequency of heterozygotes ($$2pq) $$under Hardy-Weinberg equilibrium?

Accepted Answer

$$2 	imes 0.7 	imes 0.3 = 0.42$$

Question 16

Which of the following is a likely consequence of a population bottleneck?

Accepted Answer

Decreased genetic diversity due to random loss of alleles

Question 17

Which of the following best explains why female birds often prefer males with exaggerated secondary sexual traits (e.g., bright colors, elaborate songs)?

Accepted Answer

Such traits may signal good genes or high fitness, making those males more attractive as mates.

Question 18

Which of the following is a major limitation of evolution by natural selection?

Accepted Answer

It is limited by historical constraints and trade-offs, and cannot produce perfect organisms.

Question 19

Which of the following is the best definition of microevolution?

Accepted Answer

Changes in allele frequencies within a population over time.

Question 20

Which of the following is a real-world example of gene flow?

Accepted Answer

Wolves from one population migrate and breed with wolves from a neighboring population, introducing new alleles.

Evolution, Speciation, and Diversity: Exam #1

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