Evolution Test Bank Questions

What is the observable change in the allele frequencies of a population over time called?

• selection

• microevolution

• distribution

• recombination

Natural selection that changes the distribution of a trait to favor one extreme phenotype is called

• disruptive selection.

• stabilizing selection.

• normalizing selection.

• directional selection.

In stabilizing selection, what occurs in a population?

• The population shifts toward one of two extreme phenotypes.

• Both extreme phenotypes shift toward the middle.

• The intermediate phenotype becomes more common.

• The intermediate phenotype becomes rare.

In a population of birds, intermediate beak size is selected against, and both very small and very large beak sizes are favored. What type of selection is this an example of?

• directional

• disruptive

• normal

• stabilizing

Random by chance changes in allele frequencies within a population are called

• gene flow.

• gene pool.

• genetic drift.

• sexual selection.

A small number of birds, blown off course during migration, find an island and colonize it. This population will most likely experience genetic drift as a result of the

• founder effect.

• bottleneck effect.

• sexual selection.

• mutations.

What is speciation?

• combining of two species to form one with different traits

• isolation that affects mating behavior

• timing of mating that prevents normal sexual selection

• divergence of two or more species from an existing one

A difference of chemical scents and feather displays between two bird populations is an example of what kind of isolation?

• temporal

• behavioral

• geographic

• disruptive

An earthquake causes an ocean channel to open up on an island where a low area previously existed. The island's lizard population is now separated on the two parts of the island, providing an example of

• geographic isolation.

• behavioral isolation.

• disruptive selection.

• temporal isolation.

Which of the following examples illustrates a temporal barrier to mating between populations?

• Populations of the same species of seal live on islands too far apart to swim between them for mating.

• Species of birds have elaborate courtship dances, and females select the best dancers as mates.

• Varieties of oak tree produce pollen during different seasons, so they can't pollinate one another.

• Herds of caribou misinterpret each other's mating behavior, so they fight instead of mating.