Question 1

Which of the following best describes a phylogenetic tree?

Accepted Answer

A diagram that shows the evolutionary relationships among various biological species based on similarities and differences in their physical or genetic characteristics.

Question 2

What is the most likely outcome when two diverged populations come into secondary contact and hybrid offspring have reduced fitness?

Accepted Answer

Reinforcement of divergence due to selection for traits that prevent interbreeding.

Question 3

In a scenario where two populations of fish are separated by a physical barrier and later come into contact, which process is most likely if gene flow does not reduce fitness?

Accepted Answer

Fusion of the populations back into one.

Question 4

Which of the following is a correct statement about monophyletic groups in a phylogenetic tree?

Accepted Answer

A monophyletic group includes an ancestral species and all of its descendants.

Question 5

If two closely related species of crickets come into contact and produce sterile hybrid offspring, what is the most likely evolutionary response in regions where they overlap (sympatry)?

Accepted Answer

Selection will favor increased differences in mating calls to prevent hybridization.

Question 6

Which of the following best describes a hybrid zone?

Accepted Answer

A geographic area where interbreeding occurs and hybrid offspring are common.

Question 7

A population of whitefish in a lake splits into two groups: one adapted to open water with many gill rakers, and one adapted to the benthic zone with fewer gill rakers. If these populations come into contact and hybridization does not reduce fitness, what is the most likely outcome after many generations?

Accepted Answer

The two populations will fuse, resulting in an average gill raker number between the two extremes.

Question 8

Which of the following is NOT a possible outcome of secondary contact between two diverged populations?

Accepted Answer

Immediate extinction of all other species in the ecosystem.

Question 9

In a phylogenetic tree, what does a node represent?

Accepted Answer

A common ancestor from which two or more descendant groups diverged.

Question 10

Which of the following statements about phylogenetic trees is correct?

Accepted Answer

They are hypotheses about evolutionary relationships that can be revised with new data.

Question 11

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

Accepted Answer

Selection for traits that prevent interbreeding when hybrid offspring have reduced fitness.

Question 12

A botanist is constructing a phylogenetic tree of cats. Which of the following would be the best outgroup?

Accepted Answer

A dog

Question 13

Which of the following is an example of allopatric speciation?

Accepted Answer

A river forms and splits a population of rodents, leading to genetic divergence.

Question 14

Which of the following equations correctly represents the Hardy-Weinberg equilibrium for allele frequencies $$p$$ and $$q$$?

Accepted Answer

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

Question 15

If a hybrid offspring possesses adaptive traits that allow it to thrive in a new environment, what is a possible evolutionary outcome?

Accepted Answer

Hybrid speciation, resulting in a new species.

Question 16

Which of the following is a paraphyletic group?

Accepted Answer

A group that includes an ancestral species and some, but not all, of its descendants.

Question 17

Which of the following is true about the root of a phylogenetic tree?

Accepted Answer

It represents the most recent common ancestor of all taxa in the tree.

Question 18

In the context of speciation, what is vicariance?

Accepted Answer

The physical splitting of a population into smaller, isolated groups by a barrier.

Question 19

Which of the following best explains why phylogenetic trees are considered hypotheses?

Accepted Answer

They are based on available data and can change with new evidence.

Question 20

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

Accepted Answer

Two frog species in the same pond develop different mating calls to avoid producing unfit hybrids.

Phylogenies and Speciation: Mechanisms and Outcomes

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