Question 1

Why is natural selection generally stronger on traits that affect young individuals compared to those that affect older individuals?

Accepted Answer

Because most individuals are young, and only a few reach old age, so selection acts more strongly on traits expressed early in life.

Question 2

Which of the following best explains why harmful mutations tend to accumulate and affect older ages?

Accepted Answer

Selection is weaker against mutations that affect the elderly, so these mutations are less likely to be eliminated from the population.

Question 3

In the context of population genetics, what is a bottleneck effect?

Accepted Answer

A random reduction in population size that leads to a loss of genetic diversity.

Question 4

Which scenario best illustrates the founder effect?

Accepted Answer

A small group of individuals colonizes a new island, and their genetic makeup shapes the future population.

Question 5

If a population of possums on an island lives longer than those on the mainland, what is the most likely explanation based on natural selection?

Accepted Answer

The island possums experience less predation, so selection for early reproduction is weaker, allowing for longer lifespans.

Question 6

Which population is expected to show faster aging according to the study materials?

Accepted Answer

A population with high predation rates, where few individuals survive to old age.

Question 7

Genetic drift is most likely to have a significant effect in which type of population?

Accepted Answer

Small populations where random changes can greatly affect allele frequencies.

Question 8

Which of the following is an example of intra-sexual selection?

Accepted Answer

Male elephant seals fighting for access to females.

Question 9

Why do male peacocks have large, multicolored tail feathers?

Accepted Answer

As a result of inter-sexual selection, where females choose mates based on tail feather appearance.

Question 10

According to sexual selection theory, which sex is more likely to be choosy when selecting a mate?

Accepted Answer

The sex that invests more resources in offspring.

Question 11

Which equation best represents the probability of survival to a certain age $$x in a $$population where selection is stronger on the young?

Accepted Answer

$$P(x) = e$$^{-rx}$$

Question 12

A population of 100 individuals experiences a bottleneck and is reduced to 10 individuals. What is the most likely genetic consequence?

Accepted Answer

Loss of genetic diversity due to random sampling of alleles.

Question 13

Which of the following statements about genetic drift is correct?

Accepted Answer

Genetic drift can cause allele frequencies to change randomly, especially in small populations.

Question 14

Why might traits that appear detrimental for survival, such as bright coloration in male birds, persist in a population?

Accepted Answer

Because they are favored by inter-sexual selection, where females prefer mates with these traits.

Question 15

Which of the following best describes the difference between intra-sexual and inter-sexual selection?

Accepted Answer

Intra-sexual selection involves competition between members of the same sex, while inter-sexual selection involves mate choice by the opposite sex.

Question 16

If a population is pushed off a cliff and only a few individuals survive, which evolutionary process is most likely to occur?

Accepted Answer

Genetic drift due to a bottleneck effect.

Question 17

Which formula would you use to calculate the change in allele frequency due to genetic drift in a small population?

Accepted Answer

$$\Delta p = \frac{1}{2N}$$

Question 18

Why do harmful mutations that affect older individuals tend to persist in populations?

Accepted Answer

Because selection is weaker against mutations that affect individuals after they have reproduced.

Question 19

Which of the following is a real-world example of the founder effect?

Accepted Answer

A group of finches colonizing the Galápagos Islands and evolving distinct beak shapes.

Question 20

Which sex is more likely to compete for mates in species where males invest less in offspring than females?

Accepted Answer

Males compete for females.

Evolutionary Mechanisms: Aging, Genetic Drift, and Sexual Selection

Study Guide - Practice Questions