A Researcher Has Maintained a Small Population of Fruit Flies

Multiple Choice

A researcher has maintained a small population of fruit flies in the laboratory by transferring the flies to a new culture bottle after each generation. After several generations, the viability of the flies decreased greatly. Recognizing that small population size is likely to be linked to decreased viability, which of the following approaches would be the best way to reverse this trend of decreased viability?

A) cross the flies with flies from another lab
B) reduce the number of flies that are transferred at each generation
C) transfer only the largest flies
D) change the temperature at which the flies are reared