Question 1

Which of the following best describes the Biological Species Concept?

Accepted Answer

Species are groups of populations that are reproductively isolated from other such groups.

Question 2

A population of birds is separated by a mountain range, preventing gene flow. Over time, they evolve into two distinct species. What type of speciation is this?

Accepted Answer

Allopatric speciation

Question 3

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

Accepted Answer

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

Question 4

Which mechanism of reproductive isolation occurs when the genital structures of two insect species do not fit together, preventing successful mating?

Accepted Answer

Mechanical isolation

Question 5

A plant species undergoes a mutation during meiosis resulting in offspring with double the normal chromosome number. What is this process called?

Accepted Answer

Autopolyploidy

Question 6

Which of the following is NOT a prezygotic isolation mechanism?

Accepted Answer

Hybrid sterility

Question 7

According to the Phylogenetic Species Concept, a species is defined as:

Accepted Answer

The smallest monophyletic group on a phylogenetic tree.

Question 8

Which scenario best illustrates reinforcement in speciation?

Accepted Answer

Hybrid offspring have lower fitness, leading to increased reproductive isolation.

Question 9

A population of insects adapts to two different host plants in the same geographic area, leading to reproductive isolation. What type of speciation is this?

Accepted Answer

Sympatric speciation via disruptive selection

Question 10

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

Accepted Answer

$$2n_A + 2n_B$$

Question 11

Why can't the Biological Species Concept be applied to asexual organisms?

Accepted Answer

Reproductive isolation cannot be evaluated because they do not mate.

Question 12

Which of the following is an example of postzygotic isolation?

Accepted Answer

Hybrid offspring of horses and donkeys (mules) are sterile.

Question 13

Which of the following statements about vicariance is correct?

Accepted Answer

It involves the physical splitting of a habitat, leading to allopatric speciation.

Question 14

A researcher discovers two populations of fish that look identical but have different DNA sequences. Which species concept would best help distinguish them?

Accepted Answer

Phylogenetic species concept

Question 15

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

Accepted Answer

Phylogenies are only available for a small subset of populations.

Question 16

If two populations of mice are separated by a river and cannot interbreed, which type of isolation is this?

Accepted Answer

Habitat isolation

Question 17

Which of the following best explains why hybrid zones may persist between two species?

Accepted Answer

Hybrids have intermediate fitness, allowing them to survive in a specific region.

Question 18

Which of the following is a synapomorphy used to identify a monophyletic group?

Accepted Answer

A trait found only in the common ancestor and all its descendants.

Question 19

Which of the following scenarios would most likely lead to sympatric speciation?

Accepted Answer

A mutation causes some individuals to prefer a new food source within the same habitat.

Question 20

If a hybrid offspring between two species is sterile, which type of isolation is this an example of?

Accepted Answer

Postzygotic isolation

Speciation: Concepts, Mechanisms, and Examples

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