Question 1

Which of the following best describes stabilizing selection, and what is its effect on the phenotypic distribution of a population over time?

Accepted Answer

It favors intermediate phenotypes, reducing variation and maintaining the status quo.

Question 2

A population of beetles has two alleles for shell color: G (green) and g (brown). If 36% of the population is homozygous green (GG), and the population is in Hardy-Weinberg equilibrium, what is the frequency of the g allele?

Accepted Answer

$$q = 0.4$$

Question 3

Which of the following is NOT a source of genetic variation in populations?

Accepted Answer

Genetic drift

Question 4

Which scenario best illustrates the bottleneck effect?

Accepted Answer

A population of cheetahs is reduced to a few individuals due to a natural disaster, resulting in low genetic diversity.

Question 5

According to the endosymbiont theory, which of the following is NOT evidence supporting the origin of mitochondria and chloroplasts from prokaryotic ancestors?

Accepted Answer

Both organelles are found in all prokaryotes.

Question 6

Which group is responsible for the initial production of atmospheric $$O_2 on $$Earth, and what was a major consequence of this event?

Accepted Answer

Cyanobacteria; it led to the evolution of aerobic respiration.

Question 7

Which characteristic is shared by Archaea and Eukarya, but NOT by Bacteria?

Accepted Answer

Similar RNA polymerase structure

Question 8

Which of the following is a shared derived trait that unites all members of the plant kingdom (Kingdom Plantae)?

Accepted Answer

Alternation of generations with multicellular, dependent embryos

Question 9

Which of the following animal phyla is NOT part of the Bilateria?

Accepted Answer

Cnidaria

Question 10

Which two phyla belong to the Ecdysozoa, and what is their shared derived characteristic?

Accepted Answer

Arthropoda and Nematoda; molting of the cuticle

Question 11

Which method is most appropriate for estimating the population size of a mobile animal species, such as deer, in a forest?

Accepted Answer

Mark-recapture

Question 12

Given the exponential growth equation $$\Delta N / \Delta t = rN$$, if a population of 100 rabbits has an intrinsic rate of increase $$r = 0.2$$, what is the expected population increase in one time unit?

Accepted Answer

$$\Delta N = 20$$

Question 13

Which of the following best distinguishes density-dependent from density-independent regulation of population size?

Accepted Answer

Density-dependent factors intensify as population size increases, while density-independent factors affect populations regardless of size.

Question 14

Which of the following is an example of disruptive selection in a real-world scenario?

Accepted Answer

A population of finches where both small and large beak sizes are favored due to different food sources, but medium beaks are selected against.

Question 15

Which of the following best describes the founder effect?

Accepted Answer

A new population is established by a small number of individuals, resulting in reduced genetic variation.

Question 16

Which of the following is a shared ancestral characteristic of all animals and choanoflagellates?

Accepted Answer

Flagellated cells

Question 17

Which class of arthropods includes spiders, scorpions, and ticks?

Accepted Answer

Chelicerata

Question 18

If a population of 500 birds has a birth rate $$b = 0.1$$ and a death rate $$m = 0.05$$, what is the intrinsic rate of increase $$r$$ and the expected change in population size per time unit ($$\Delta N$$)?

Accepted Answer

$$r = 0.05; \Delta N = 25$$

Question 19

Which of the following is a shared derived trait of Lophotrochozoa?

Accepted Answer

Presence of a lophophore or trochophore larva

Question 20

Which of the following best describes the process of gastrulation in animal development?

Accepted Answer

The inward folding of the blastula to form embryonic germ layers

BIOL 1307 Exam 3 Review – Step-by-Step Study Guidance

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