Question 1

Which of the following best describes directional selection?

Accepted Answer

Individuals at one phenotypic extreme have higher fitness than others, causing the population mean to shift.

Question 2

In a population of peppered moths, pollution causes trees to darken. Over time, the frequency of dark-colored moths increases. Which type of selection is this an example of?

Accepted Answer

Directional selection

Question 3

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

Accepted Answer

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

Question 4

A population of birds has a wide range of beak sizes. If birds with very small and very large beaks survive better than those with medium-sized beaks, what type of selection is occurring?

Accepted Answer

Disruptive selection

Question 5

Which of the following is a misconception about evolution?

Accepted Answer

Natural selection always leads to the 'best' possible trait.

Question 6

Which scenario best illustrates stabilizing selection?

Accepted Answer

Human babies of average birth weight have higher survival rates than those with very low or very high birth weights.

Question 7

Sexual selection can sometimes conflict with natural selection. Which of the following is an example of this conflict?

Accepted Answer

Brightly colored male birds attract more mates but are also more visible to predators.

Question 8

Which of the following is NOT a prezygotic reproductive isolation mechanism?

Accepted Answer

Hybrid sterility

Question 9

According to the biological species concept, what defines a species?

Accepted Answer

A group of organisms that can interbreed and produce viable, fertile offspring.

Question 10

Which species concept is most useful for identifying cryptic species that differ in traits other than morphology?

Accepted Answer

Phylogenetic species concept

Question 11

A population of iguanas experiences increased air and water temperatures due to climate change. If larger males have higher foraging efficiency and attract more mates, what is the likely evolutionary outcome?

Accepted Answer

Mean body size will increase due to directional selection.

Question 12

Which of the following is an example of postzygotic isolation?

Accepted Answer

Hybrid offspring are sterile and cannot reproduce.

Question 13

Which process can lead to genetic isolation and ultimately speciation?

Accepted Answer

Physical separation of populations by a geographic barrier

Question 14

Which of the following best describes allopatric speciation?

Accepted Answer

Speciation occurs when populations are separated by a physical barrier.

Question 15

If two populations of birds with different coloration are brought together and produce fertile offspring that breed with each other and the parent populations, what does this indicate about their species status under the biological species concept?

Accepted Answer

They are the same species.

Question 16

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

Accepted Answer

It may fail to identify cryptic species that differ in non-morphological traits.

Question 17

Which of the following statements about gene flow is correct?

Accepted Answer

Gene flow decreases genetic differences between populations.

Question 18

Which of the following is a real-world example of disruptive selection?

Accepted Answer

Gall flies with either very small or very large galls survive better than those with medium-sized galls.

Question 19

Which of the following equations correctly represents the sum of allele frequencies in a population?

Accepted Answer

$p + q = 1$

Question 20

Which species concept defines a species as a monophyletic group based on evolutionary history?

Accepted Answer

Phylogenetic species concept

Mechanisms of Evolution: Selection and Speciation

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