Question 1

Which of the following best describes Darwin's concept of 'descent with modification'?

Accepted Answer

All life is connected by common ancestry, and descendants accumulate adaptations over time.

Question 2

A population of mosquitoes exposed to DDT developed resistance over time. Which mechanism best explains this evolutionary change?

Accepted Answer

Natural selection acting on heritable variation in the population.

Question 3

Which of the following is the ultimate source of genetic variation in a population?

Accepted Answer

Mutation.

Question 4

A fossil record reveals a sequence of organisms from simple to complex. What does this evidence most strongly support?

Accepted Answer

The concept of extinction and evolutionary change over time.

Question 5

Which equation is used to determine whether a population is in Hardy-Weinberg equilibrium?

Accepted Answer

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

Question 6

A population of iguanas has allele frequencies of $$ p = 0.8 $$ and $$ q = 0.2 . $$What is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$$ 0.32 $$

Question 7

Which of the following is NOT a condition required for Hardy-Weinberg equilibrium?

Accepted Answer

Natural selection favoring certain alleles.

Question 8

Which mechanism of microevolution is most likely to reduce genetic diversity after a natural disaster drastically reduces population size?

Accepted Answer

Genetic drift (bottleneck effect).

Question 9

In a population of finches, individuals with either very large or very small beaks survive better than those with intermediate beaks. What type of selection is this?

Accepted Answer

Disruptive selection.

Question 10

Why can't an individual organism evolve?

Accepted Answer

Evolution is a process that occurs at the population level, not the individual level.

Question 11

Which of the following best explains why antibiotic resistance evolves in bacteria?

Accepted Answer

Antibiotics select for bacteria that already possess resistance alleles.

Question 12

Which of the following is an example of a vestigial structure?

Accepted Answer

The human appendix, which has lost its original function.

Question 13

Which process consistently leads to adaptive evolution?

Accepted Answer

Natural selection.

Question 14

A population of birds is isolated on an island. Over generations, their allele frequencies change due to random events. What is this process called?

Accepted Answer

Genetic drift (founder effect).

Question 15

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

Accepted Answer

Human birth weight, where intermediate weights have lower mortality.

Question 16

What is the biological definition of relative fitness?

Accepted Answer

The contribution an individual makes to the gene pool of the next generation relative to others.

Question 17

Which of the following is a mechanism by which sexual reproduction increases genetic variation?

Accepted Answer

Crossing over during meiosis.

Question 18

Why does natural selection tend to reduce genetic variation more in haploid organisms than in diploid organisms?

Accepted Answer

Recessive alleles are not hidden in haploid organisms.

Question 19

Which of the following is an example of balancing selection?

Accepted Answer

Heterozygote advantage in sickle-cell anemia.

Question 20

Which statement best explains why natural selection cannot produce perfect organisms?

Accepted Answer

Evolution is limited by historical constraints and adaptations are often compromises.

How Populations Evolve: Mechanisms and Evidence of Evolution

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