Consider the following two scenarios: 1)A flash-flood sweeps through an area and random lemmings are killed,resulting in a change in lemming phenotype in subsequent generations;2)A flash-flood sweeps through an area and some lemmings are able to survive because they are able to hold their breath longer than other lemmings,resulting in a change in lemming phenotype in subsequent generations.What are the primary differences between the two scenarios?
A)Scenario 1 represents genetic drift because changes in the population were not adaptive,while Scenario 2 represents natural selection because some individuals were better adapted than other individuals.
B)Scenario 1 represents natural selection because changes in the population were adaptive,while Scenario 2 represents genetic drift because changes in the population were due to higher fitness of some individuals.
C)Both scenarios represent genetic drift because the flash-flood is a random event.
D)Both scenarios represent natural selection because some individuals survived in each scenario.

Question

Quizplus · Accepted Answer

In Scenario 1, the changes in phenotype were not due to any selective advantage, but instead occurred randomly as a result of the flash-flood. This is genetic drift. In Scenario 2, the survival of some lemmings was due to a specific trait that they possessed, holding their breath longer. This trait gave them a selective advantage and allowed them to survive the flash-flood, resulting in a change in the phenotype of subsequent generations. This is natural selection.

Consider the Following Two Scenarios: 1)A Flash-Flood Sweeps Through an Area