Question

a) Define selection, and explain what differentiates it from drift.
b) Discuss three different levels of organization at which selection can act to drive evolution. Illustrate each case with an example, illustrating at least one evolutionary outcome resulting from selection at that level.

essay style answer 300-500 words

Answer 1

A) Natural selection is the selection of more fitter and better adapted and suited individuals to survive in the current conditions. Whereas drift is the random increase or decrease in allelic frequencies in population due to a matter of chance or randomness.

B)Genic selection is selection at the gene level,b

Where some of the genes will be selected over the other.

For eg.  meiotic drive where one gametic type is transmitted into the gamete pool in excess or deficiency. Like sex ratios are tend to be maintained at 50:50 ratios. But may be male or female ratio may become higher due to genic selection and then may stabilize also.

Kin selection or altruistic behavior seen in many species of animals that live in groups. They give warning signals for alerting about dangers like predators. But many times this puts the caller in danger , but helps the greater good that is selection of kin over the organism.

For eg. Mothers in mammals take care alot of their children which is thought that it reduces their fitness but they are actually nurturing the future generation.

This is actually Individual level selection- where selection is at individual level. And the better individuals are selected.

Intergroup selection- where the better group will be selected. It depends on the overall genotype of the group. One group being more superior than the other. Groups with more number of altruistic individuals will be selected more. The best way to do cooperation.

For eg. In ants the group work as a unit for best possible productivity, defense offense , and different ants perform different functions with altruistic behavior also.