Q: A population of beetles has two alleles for color: green (G) and brown (g). If the frequency of G is 0.7 and g is 0.3, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

$2pq = 2 \times 0.7 \times 0.3 = 0.42$

Question 1

Which of the following best describes Darwin's concept of natural selection?

Accepted Answer

Individuals with heritable traits that increase survival and reproduction tend to leave more offspring.

Question 2

According to Hardy-Weinberg equilibrium, which equation represents the expected genotype frequencies in a population?

Accepted Answer

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

Question 3

A population of beetles has two alleles for color: green (G) and brown (g). If the frequency of G is 0.7 and g is 0.3, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$2pq = 2 	imes 0.7 	imes 0.3 = 0.42$

Question 4

Which evolutionary process is most likely responsible for the random loss of alleles in a small population after a natural disaster?

Accepted Answer

Genetic drift

Question 5

Which of the following is NOT one of Darwin's four postulates of natural selection?

Accepted Answer

All individuals survive and reproduce equally.

Question 6

A population of birds is separated by a mountain range, preventing them from interbreeding. Over time, the two groups develop distinct traits. What type of speciation is this?

Accepted Answer

Allopatric speciation

Question 7

Which mechanism of evolution can introduce new alleles into a population from another population?

Accepted Answer

Gene flow

Question 8

Which of the following is an example of postzygotic reproductive isolation?

Accepted Answer

Hybrid offspring are sterile.

Question 9

In a population, the frequency of allele A is 0.4 and allele a is 0.6. What is the expected frequency of homozygous recessive individuals under Hardy-Weinberg equilibrium?

Accepted Answer

$q^2 = 0.6^2 = 0.36$

Question 10

Which evolutionary process is most likely to increase genetic variation in a population?

Accepted Answer

Mutation

Question 11

Which type of selection favors individuals with intermediate traits and reduces variation in a population?

Accepted Answer

Stabilizing selection

Question 12

A researcher observes that two species of frogs breed at different times of the year. What type of reproductive isolation is this?

Accepted Answer

Temporal isolation

Question 13

Which of the following statements about phylogenetic trees is correct?

Accepted Answer

They show the evolutionary relationships among species.

Question 14

Which process can result in speciation without geographic isolation?

Accepted Answer

Sympatric speciation

Question 15

A population of plants undergoes a mutation that doubles their chromosome number, resulting in a new species. What is this process called?

Accepted Answer

Polyploidy

Question 16

Which of the following is a direct result of gene flow between populations?

Accepted Answer

Decreased genetic differences between populations

Question 17

Which scenario best illustrates disruptive selection?

Accepted Answer

Birds with very small or very large beaks survive better than those with medium-sized beaks.

Question 18

Which of the following mechanisms is LEAST likely to cause evolution in a population?

Accepted Answer

Hardy-Weinberg equilibrium

Question 19

A scientist wants to build a phylogenetic tree for several species. Which type of data would be most useful?

Accepted Answer

DNA sequence data

Question 20

Which of the following is an example of prezygotic reproductive isolation?

Accepted Answer

Gametes of two species cannot fuse.

Study Guide: Evolution, Natural Selection, and Phylogeny

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