Exam 15: How Populations Evolve

Which of the following is MOST likely to experience genetic drift?

The male peacock's beautiful tail is really a trade-off between:

In one butterfly species, the colors of individuals range from white to black, with many shades of gray in between. If the butterflies in a mountain population become more and more similar in color over several generations (for example, if most butterflies are the same shade of gray), what kind of evolutionary force is likely acting on the population?

As predator and prey species acquire new adaptations to help them survive the constant "arms race" between them, what evolutionary phenomenon is occurring?

In an equilibrium population:

Imagine you are studying leaf size in a large population of plants over several years. In one year of your study there is a below-average amount of rainfall, and the following year the average leaf size in the population is smaller than before. However, the amount of variation in leaf size is the same and the population size doesn't change. Other scientists have done experiments showing that small leaves are better adapted to dry conditions than large leaves. What has most likely occurred?

Multidrug-resistant bacteria:

Which of the following phenomena favors individuals with average phenotypes over those with extreme phenotypes?

A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, 2pq represents:

Shrews have been documented to travel across frozen lakes and establish populations on previously uninhabited islands. This is an example of:

In a population, the most common phenotype represents the dominant allele. True or False?

Natural selection causes genetic changes in an individual. True or False?

In a certain species of salmon, some adult males are extremely large whereas other adult males are very small, compared to the females. There are no intermediate-sized adult males in the population. This is probably due to:

Female finches, which do not sing, tend to choose to mate with males who sing a specific, elaborate song. This is an example of:

The extreme loss of genetic diversity that has occurred in cheetah populations due to overhunting is the result of:

A bird comes in a range of phenotypes, from white through gray to black. Disruptive selection favors the gray phenotype. True or False?

Evolution by natural selection is:

If two or more phenotypes in a population are both favored by selection, what is happening?

The net migration of alleles into or out of a population from neighboring populations is called:

________ is due to chance events that change the allele frequencies in small populations.