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231 The area covered by tropical rain forest is reduced by millions of hectares per year due to agriculture and logging. Which of the following best describes a likely result of tropical rain forest deforestation?

A: Populations of plants and animals will decrease as more rain forest disappears, leading to a decrease in biodiversity.

B: An increase of soil moisture will lead to a rapid increase in new vegetation coverage.

C: An increase in atmospheric carbon dioxide will lead to higher levels of ultraviolet radiation reaching the surface of Earth.

D: More oxygen will be available to other organisms as plant numbers decrease.

Microbiology MCQ
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232 Which of the following includes the most likely change in the coloration of the beetle population after pollution and a correct rationale for the change?

A: The coloration range shifted toward more light-colored beetles, as in diagram I. The pollution helped the predators find the darkened tree trunks.

B: The coloration in the population split into two extremes, as in diagram II. Both the lighter-colored and the darker-colored beetles were able to hide on the darker tree trunks.

C: The coloration range became narrower, as in diagram III. The predators selected beetles at the color extremes.

D: The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lighter-colored beetles were found more easily by the predators than were the darker-colored beetles.

Microbiology MCQ
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233 Five new species of bacteria were discovered in Antarctic ice core samples. The nucleotide (base) sequences of rRNA subunits were determined for the new species. The table below shows the number of nucleotide differences between the species. Which of the following phylogenetic trees is most consistent with the data?

A: C)

B: A

C: B

D: D

Microbiology MCQ
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234 The biologist discovered that from 1988 to 1993, the average beak size declined to pre-1981 levels. The reversal in beak size from 1988 to 1993 was most likely related to which of the following events?

A: A loss of food supply for the finches

B: The end of the drought

C: An increase in drought conditions

D: An increase in predators consuming finches

Microbiology MCQ
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235 Which of the following best describes the mechanism behind the change in beak size in the finch population?

A: The formation of two new finch species from a single parent species.

B: A change in gene frequencies in the finch population due to selective pressure from the environmental change.

C: A new allele appearing in the finch population as a result of mutation.

D: The achievement of dynamic equilibrium in the finch population as a result of homeostasis.

Microbiology MCQ
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236 Which of the following statements might best explain the increase in average beak size in the finch population during the drought?

A: Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring.

B: Finches with bigger beaks can attack and kill finches with smaller beaks.

C: Finches with bigger beaks possess more powerful flight muscles and are able to find more food.

D: Finches that crack large seeds develop larger beaks over time.

Microbiology MCQ
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237 Which of the following procedures was most likely followed to determine the change in beak size?

A: A few finches were trapped in 1981 and again in 1987, and their beak sizes were compared.

B: The beak size in fifteen finches was measured in 1987, and the beak size in the original finches was determined by estimation.

C: The beak size in a large number of finches was measured every year from 1981 to 1987.

D: Finches were captured and bred in 1981, and the beak size of the offspring was measured.

Microbiology MCQ
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238 In the context of the Hardy-Weinberg equilibrium, which of the following factors would most likely disturb the genetic equilibrium of a population?

A: Migration of individuals into the population.

B: Random mating within the population.

C: Absence of mutation within the population.

D: No natural selection occurring within the population.

Microbiology MCQ
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239 The enzyme pepsin functions optimally at a low pH. If pepsin is present in the stomach and the stomach’s pH increases significantly above its optimal range, what will likely happen to the enzyme activity?

A: The enzyme will continue to function at the same rate.

B: The enzyme will function more efficiently due to the higher pH.

C: The enzyme will denature, leading to a decrease in activity.

D: The enzyme will become inactive but can be reactivated by lowering the pH.

Microbiology MCQ
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240 The probability of obtaining a homozygous recessive individual in the offspring from a cross between two heterozygous parents is

A: 25%

B: 50%

C: 75%

D: 100%

Microbiology MCQ
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