Question

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.

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

Answer 1

Here are 3-5 sentences that describe how mosquitoes may have come to develop resistance to DDT:

• Natural selection: Over time, mosquitoes that were naturally resistant to DDT were more likely to survive and reproduce, passing on their resistance genes to their offspring. This led to a population of mosquitoes that were increasingly resistant to DDT.
• Genetic mutation: Genetic mutations can occur randomly in any population. In some cases, these mutations can make an individual more resistant to a particular insecticide. If this individual survives and reproduces, its offspring will also be resistant to the insecticide.
• Environmental factors: Some environmental factors, such as pollution, can also increase the rate of genetic mutations. This can lead to an increase in the number of mosquitoes that are resistant to insecticides.

As a result of these factors, mosquito populations can develop resistance to insecticides over time. This can make it difficult to control mosquito-borne diseases.