Exam 17: The Means of Evolution: Microevolution

The greater prairie chicken once flourished on the prairies of Illinois.The conversion of prairie to farmland reduced their numbers from millions to only 50 birds by 1993.Poor genetic diversity resulted in only 50 percent of eggs hatching.Bringing in birds from neighboring states increased their genetic diversity,which improved the egg-hatching rate to 90 percent.These changes in genetic diversity were the result of:

Mutations:

The most important kind of selection acting on a well-adapted population in a relatively constant environment is:

The smallest unit that can participate in evolution is a ________.

Even though in a similar habitat,a founder population that breaks away from the parent population may become very different because of:

Genetic drift occurs when:

Habitats set aside for endangered species are often sectioned into areas by roads,producing separate small populations.This causes problems in conservation because it reduces:

Refer to the scenario below, and then answer the following question(s). Two European men and two Polynesian women settled on a previously uninhabited tropical island. All four of the settlers have brown eyes, a dominant trait, but one of the Europeans is heterozygous and carries the recessive gene for blue eyes. -No new settlers arrive,and nobody leaves the island.After a few generations,the percentage of blue-eyed individuals increases from the original zero to 25 percent.This is probably due to which of the following factors?

Without mutation,evolution would eventually cease,because mutations create the variation that evolution acts upon.

A population of salamanders migrates from a sand beach to a pebble beach and evolves over many generations from a solid color to speckled coloration.This process is called stabilizing selection.

Which of the following processes is not an agent of microevolution?