Question 1

Which of the following best describes the two-step process of speciation?

Accepted Answer

Genetic isolation followed by genetic divergence

Question 2

According to the biological species concept, what is the main criterion for identifying species?

Accepted Answer

Reproductive isolation

Question 3

Which of the following is a disadvantage of the morphological species concept?

Accepted Answer

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

Question 4

A population of birds is split into two by the formation of a new river. Over time, the two populations evolve independently. What type of speciation is this?

Accepted Answer

Allopatric speciation by vicariance

Question 5

Which of the following mechanisms can lead to prezygotic isolation?

Accepted Answer

Individuals of different species are prevented from mating successfully

Question 6

Why is speciation by polyploidy especially common in plants?

Accepted Answer

Polyploids can tolerate higher levels of self-fertilization and have increased genetic diversity

Question 7

Which equation best represents the Hardy-Weinberg equilibrium for allele frequencies in a population?

Accepted Answer

$$p^2 + 2pq$$ + $$q^2 = 1$

Question 8

A new species of plant arises instantly due to a chromosome-level mutation that doubles its chromosome number. What is this process called?

Accepted Answer

Autopolyploidy

Question 9

Which of the following is a key feature of the phylogenetic species concept?

Accepted Answer

Species are identified as the smallest monophyletic group on a phylogenetic tree

Question 10

In a hybrid zone, what determines whether the zone is narrow or wide?

Accepted Answer

The fitness of hybrid offspring and the extent of interbreeding between parental species

Question 11

Which of the following scenarios is an example of reinforcement?

Accepted Answer

Natural selection favors traits that prevent interbreeding between two diverged populations

Question 12

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

Accepted Answer

It can identify cryptic species that differ in non-morphological traits

Question 13

A population of finches colonizes a new island and evolves larger beaks due to genetic drift and natural selection. What is likely to happen if gene flow with the original population continues?

Accepted Answer

The two populations will not become separate species

Question 14

Which of the following best describes allopolyploidy?

Accepted Answer

Offspring are produced when parents of different species mate and an error in mitosis results in viable, nonsterile offspring

Question 15

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

Accepted Answer

Formation of river systems in the Amazon basin splitting ancestral populations of trumpeters

Question 16

What is the expected outcome when two populations that have diverged come into contact and prezygotic isolation exists?

Accepted Answer

Mating between populations is rare and gene flow is minimal

Question 17

Which of the following events can initiate sympatric speciation?

Accepted Answer

Disruptive selection based on ecological niches or mate choice

Question 18

A hybrid species of flower arises from the interbreeding of two previously diverged species and is able to grow in a drier habitat than either parent. What does this illustrate?

Accepted Answer

Hybridization can result in new species with unique ecological characteristics

Question 19

Which of the following statements about gene flow is correct?

Accepted Answer

Gene flow tends to homogenize allele frequencies between populations

Speciation: Mechanisms and Concepts (Chapter 24 Study Notes)

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