Natural Selection and Evolution Practice

Some organisms have genes that improve their ability to survive and reproduce. If the genes also help their offspring survive and reproduce, then which of the following will most likely increase?

• The frequency of the genes in one individual

• The number of genes in one chromosome

• The frequency of the genes in the population

• The frequency of the genes in the population

How does Natural Selection work to change populations?

Explain the relationship between Natural Selection and Evolution:

According to Darwin's proposed theory of evolution, species of organisms:

• change over time

• are not related to fossil remains

• do not vary from one location to another

• remain unchanged when the environment changes

Adaptations that result from natural selection are expected to increase the fitness of an organism. In terms of natural selection, which of the following best describes fitness?

• Being able to escape from predators

• Being among the strongest organisms in a population

• Being able to survive, find a mate, and produce offspring

• Being able to survive long enough to reach the adult stage

Differences among individuals of a single species are referred to as ___

• artificial selection

• genetic variation

• survival of the fittest

• environmental adaptation

Which would an animal breeder use to produce cows that give more milk?

• overproduction

• genetic isolation

• acquired characteristics

• artificial selection

The photograph shows monarch butterflies landing on plants where there are thousands of other monarch butterflies. These butterflies feed on milkweed plants as they travel south for the winter, covering distances of 5,000 km or more each year. However, the population of these butterflies has been steadily declining over the last 20 years. 

What is the most likely reason the population of these butterflies has been declining?

• The number of bird species evolving to prey on butterflies has increased.

• The butterflies are evolving to tolerate cold weather in the northern United States and southern Canada.

• The increase in yearly temperatures has warmed the northern habitats.

• The number of milkweed plants along the butterflies’ migratory route has decreased.

The green frog (Lithobates clamitans clamitans) is found in many parts of the United States. The table contains some information about this frog.

Why does the ability to lay 1,000 to 5,000 eggs increase the fitness of the species L. clamitans clamitans?

• It increases opportunities for offspring to compete for limited resources.

• It increases the probability that some offspring will survive long enough to reproduce.

• It increases the probability that moving water will promote gene flow from one population to another.

• It increases the chance of the recombination of alleles, leading to genetic drift in the population.

Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment?

• Mutations are a source of variation in the species.

• Mutations are the cause of disease in the species.

• Mutations are not harmful when they occur in somatic cells of the species.

• Mutations are always passed on to subsequent generations of the species.