DDT is an insecticide that was used extensively in the mid-1900s to kill mosquitoes. It was very effective at first, but after a
few decades DDT became less effective at killing mosquitoes because many populations had evolved resistance to DDT. Which of the following conditions would biologists say was required for the evolution of DDT resistance in a population? a. A few mosquitoes in the population were resistant to DDT before it was ever used.
b. Mosquitoes in the population learned to adapt to the high levels of DDT in the environment.
c. The mosquito population needed to evolve DDT resistance in order to avoid extinction.
d. Exposure to DDT caused specific, nonrandom mutations for DDT resistance within the population.
Insect populations can develop resistance to insecticides over time. The evolution of resistance is associated with an increase in the frequency of adaptive genes in the population.
In the case above described it is expected that a few mosquitoes in the population were resistant to DDT before it was ever used (Option a is correct).
Dichlorodiphenyltrichloroethane (DDT) is a pesticide used in agriculture.
After exposure to DDT, those individuals in the mosquito population that didn't carry gene variants (i.e., alleles) associated with the resistance to this pesticide died.
Subsequently, insects having adaptive alleles associated with DDT resistance survived and reproduced, thereby increasing the frequency of adaptive genes/alleles in the population.
The reason why is because A only pairs with T, and G only pairs with C. So, if you have a strand with GGTCTA, the only possible pairing for that to replicate is CCAGAT.
