Bio homework ten points?

Question

A farmer spray a certain pesticide over his crops several times during the growing season to kill a particular species of insect. explain why the farmer begins to see increased numbers of that insect species in the growing season. please in detail

Answer 1

As the farmer continues to use the same pesticide, eventually the species of insect becomes immune or resistant to the chemical. This occurs as when a few live the initial spray they breed and make more resistant off-spring the cycle then continues until the pesticide is useless and the species is nearly completely resistant.

say there are 2 survivors, they breed out come more. The new generation breeds and so on. Every time the population builds up and becomes more resistant. Survival off the fittest...

Answer 2

The answer is simply evolution.  As the farmer sprays his crop with pesticides, it kills most of the insects.  However, due to the genetic differences between individual insects, some of them have a mutation that makes them resistant to the pesticide.  The resistant insects therefore survive and reproduce in greater numbers.  Every time the farmer sprays his crops, he kills off only the insects that are susceptible to the pesticide, and those that are resistant survive in greater numbers, and therefore each succesive genereation has more and more resistant insects.  This is why multiple types of pesticides are necessary for efficient eradication.

I hope I explained this well enough, if you have any more questions feel free to ask me directly.