Question

Explain the resistance of mosquitoes to pesticides such as DDT.

Answer 1

Resistance of mosquitoes to pesticides such as DDT can be explained by natural selection. Initially, when DDT was first applied, it was very effective in killing mosquitoes, significantly reducing their population. However, within any large population of mosquitoes, there are some individuals that naturally possess genetic variations making them resistant to DDT. These resistant mosquitoes survived the pesticide applications while the susceptible ones died.

As DDT use continued, these resistant mosquitoes reproduced and passed their resistance genes to subsequent generations. Over time, the mosquito population became dominated by DDT-resistant individuals, rendering the pesticide ineffective.

Thus, the use of DDT created a selective pressure favoring mosquitoes with resistance traits, and natural selection led to the survival and increase of these resistant mosquitoes in the population. This process exemplifies how genetic variation and environmental pressures can drive evolutionary change in populations exposed to pesticides.