Question 1

Which of the following best describes the Biological Species Concept?

Accepted Answer

Species are defined by their ability to interbreed and produce viable, fertile offspring.

Question 2

A population of birds is separated by a newly formed river, preventing them from interbreeding. Over time, the two groups evolve independently. This is an example of:

Accepted Answer

Allopatric speciation

Question 3

Which of the following is a limitation of the Morphospecies Concept?

Accepted Answer

It cannot distinguish cryptic species that differ in non-morphological traits.

Question 4

Which mechanism is an example of prezygotic isolation?

Accepted Answer

Mating occurs but eggs and sperm are incompatible.

Question 5

A botanist discovers a plant population with twice the normal number of chromosomes due to an error in meiosis. This is an example of:

Accepted Answer

Autopolyploidy

Question 6

Which of the following is a disadvantage of the Phylogenetic Species Concept?

Accepted Answer

It may lead to the recognition of many more species than other concepts.

Question 7

Which of the following best illustrates reinforcement in the context of speciation?

Accepted Answer

Natural selection favors traits that prevent interbreeding between two populations after secondary contact.

Question 8

Which of the following is NOT a type of prezygotic isolation?

Accepted Answer

Hybrid sterility

Question 9

A hybrid zone forms between two closely related species of frogs. Over time, hybrids have lower fitness than either parent species. What is the most likely evolutionary outcome?

Accepted Answer

Reinforcement of reproductive barriers

Question 10

Which of the following scenarios best exemplifies sympatric speciation?

Accepted Answer

A population of insects evolves reproductive isolation due to adaptation to different host plants within the same geographic area.

Question 11

Which of the following equations correctly represents the formation of an allopolyploid from two different species, A and B, each with chromosome number $$n$$?

Accepted Answer

$$n_A + n_B \rightarrow 2n_{AB}$$

Question 12

Why can't the Biological Species Concept be applied to fossil species?

Accepted Answer

Reproductive isolation cannot be evaluated in fossils.

Question 13

Which of the following is an example of vicariance leading to speciation?

Accepted Answer

A river changes course, splitting a population of rodents into two isolated groups.

Question 14

Which of the following is a synapomorphy used in the Phylogenetic Species Concept?

Accepted Answer

A unique homologous trait shared by all members of a monophyletic group.

Question 15

A researcher finds that two populations of beetles look identical but do not interbreed in nature. Which species concept would most likely consider them separate species?

Accepted Answer

Biological Species Concept

Question 16

Which of the following best describes disruptive selection in sympatric speciation?

Accepted Answer

Selection favors individuals at both extremes of a trait, leading to reproductive isolation within the same geographic area.

Question 17

Which of the following is a real-world example of postzygotic isolation?

Accepted Answer

Mules, which are sterile hybrids produced by mating a horse and a donkey.

Question 18

If two populations of plants in the same area become reproductively isolated due to a mutation that doubles the chromosome number in one population, what is this process called?

Accepted Answer

Sympatric speciation by autopolyploidy

Question 19

Which of the following statements about gene flow and speciation is correct?

Accepted Answer

A lack of gene flow between populations is necessary for speciation to occur.

Question 20

Which of the following best explains why the Phylogenetic Species Concept can be applied to both sexual and asexual organisms?

Accepted Answer

It is based on evolutionary history and shared derived traits, not reproductive compatibility.

Speciation: Concepts, Mechanisms, and Processes

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