Mosquitoes can carry and transmit many diseases to humans. In the past, the insecticide DDT was heavily used to reduce mosquito populations in order to reduce instances of disease transmission. However, after some time, mosquito populations developed a resistance to DDT, which made the DDT less effective in reducing mosquito populations.

Question

Based on what you’ve learned about natural selection, in 3–5 sentences, describe how mosquitoes may have come to develop this resistance.

(4 points)

Answer 1

Mosquitoes may have developed resistance to DDT through natural selection. Initially, there may have been a small number of mosquitoes in the population with a genetic variation that made them less susceptible to the effects of DDT. When DDT was heavily used, the mosquitoes that were not impacted by the insecticide were more likely to survive and reproduce, passing on their resistance gene to their offspring. Over time, this resistance gene became more prevalent in the population as those mosquitoes continued to survive and reproduce, leading to a population of mosquitoes that were largely resistant to DDT.