Q7. DDT is an insecticide that was used extensively in the mid-1900s to kill mos
ID: 83874 • Letter: Q
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Q7. 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 few mosquitoes in the population were resistant to DDT before it was ever used Mosquitoes in the population learned to adapt to the high levels of DDT in the environment. O The mosquito population needed to evolve DDT resistance in order to avoid extinction O Exposure to DDT caused specific, nonrandom mutations for DDT resistance within the population. Use the following passage to answer the next two questions. Ducks are aquatic birds. Their feet are webbed and this trait makes them fastswimmers, Biologists believe that ducks eolvedfrom andbirds that idnothave webbed feet. The amount of webbing on a duck's feet is a heritable trait. Q8. While webbed feet were evolving in ancestral ducks, with each generation: Most ducks had about the same amount of webbing on their feet as their parents. e do Most ducks had more webbing on their feet than their parents. O Most ducks had less webbing on their feet than their parents. o The amount of webbing on ducks' feet had no relationship with the amount their parents had would naf see any changeExplanation / Answer
Ans 7) The exposure to DDT caused specific, non random mutations for DDT resistance within the population.
It was found that genetic mutation causes DDT resistance. It was seen that a single mutation in GSTe2gene takes place that leads the insect to break down DDT making it no longer toxic to the insect. GSTe2
Ans 8 ) Most ducks had more webbing on their feet than their parents
The offsprings are genetically similar to their parents but with the little adaption and mutation, there is little changes with the coming generation. Hence, the survival potential of the offspring enhances with little more webbing than parents as they are inclined toward water based birds. Since with moving generation, ducks are moving towards water based inclination, webbing gets slightly more developed in offspring compared to parents.
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