Question 1

Which of the following best distinguishes microevolution from macroevolution?

Accepted Answer

Microevolution refers to changes in allele frequencies within a population over time, whereas macroevolution refers to broad patterns of evolutionary change above the species level.

Question 2

Which of the following is NOT a limitation of the biological species concept?

Accepted Answer

It does not account for gene flow between populations.

Question 3

A population of frogs is separated by a newly formed river, preventing gene flow. Over time, the two populations diverge genetically and can no longer interbreed even if brought together. This is an example of:

Accepted Answer

Allopatric speciation

Question 4

Which of the following is an example of a prezygotic reproductive isolating barrier?

Accepted Answer

Mating occurs at different times of the year.

Question 5

Polyploidy is a common mechanism of speciation in plants. Which of the following best describes how polyploidy can lead to sympatric speciation?

Accepted Answer

Polyploid individuals can only mate with other polyploids, creating reproductive isolation within the same geographic area.

Question 6

Which of the following scenarios best illustrates habitat isolation as a prezygotic barrier?

Accepted Answer

Two species of garter snakes live in the same region, but one lives in water and the other on land.

Question 7

A hybrid zone forms between two closely related species of butterflies. Over time, hybrids have lower fitness than either parent species, and the zone narrows. This outcome is best described as:

Accepted Answer

Reinforcement

Question 8

Which of the following is a postzygotic reproductive isolating barrier?

Accepted Answer

Hybrid sterility

Question 9

According to the biological species concept, what must occur for a population of humans on Mars to be considered a new species from those on Earth?

Accepted Answer

They must accumulate genetic differences that prevent successful interbreeding with Earth humans.

Question 10

Which of the following best describes the difference between the morphological and phylogenetic species concepts?

Accepted Answer

The morphological species concept uses physical characteristics, while the phylogenetic species concept defines species as the smallest group sharing a common ancestor.

Question 11

Which of the following is NOT a possible outcome when closely related species meet in a hybrid zone?

Accepted Answer

Instantaneous extinction of both parent species

Question 12

Which of the following best explains why speciation can occur rapidly in some cases, according to the punctuated equilibrium model?

Accepted Answer

Speciation occurs in rapid bursts, often following environmental changes or the formation of new habitats.

Question 13

Which of the following is an example of gametic isolation?

Accepted Answer

Two species of sea urchins release sperm and eggs into the water, but the sperm cannot fertilize the eggs of the other species.

Question 14

A scientist observes that two populations of insects in the same forest have developed different mating calls, preventing interbreeding. This is an example of:

Accepted Answer

Behavioral isolation

Question 15

Which of the following statements about speciation is TRUE?

Accepted Answer

Speciation can occur both gradually and rapidly, depending on environmental and genetic factors.

Question 16

Which of the following best describes the role of sexual selection in sympatric speciation?

Accepted Answer

Sexual selection can cause reproductive isolation by favoring certain traits, leading to divergence within the same population.

Question 17

Which of the following is a real-world example of allopatric speciation?

Accepted Answer

A population of squirrels is separated by the formation of the Grand Canyon, leading to the evolution of two distinct species.

Question 18

Which of the following equations could be used to calculate the frequency of a particular allele in a population, a key concept in microevolution?

Accepted Answer

$$p + q = 1$$

Question 19

Which of the following best explains why hybrid zones can complicate the application of the biological species concept?

Accepted Answer

Hybrid zones demonstrate that reproductive isolation is sometimes incomplete, allowing gene flow between species.

Question 20

Which of the following is NOT a prezygotic isolating mechanism?

Accepted Answer

Hybrid sterility

Speciation and the Origin of Species: Study Guide and Key Concepts

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