Question

Read the sources given and answer any four from the questions given below:

Genetic drift is a mechanism of evolution in which allele frequencies of a population change over generations due to chance. Its effects is strongest in small populations. It usually results in the loss of some alleles altogether. It has major effects when a population is sharply reduced in size by a natural disaster (bottleneck effect) or when a small group splits off from the main population to form a colony (founder effect). The bottleneck effect happens when natural disasters like earthquakes, floods, fires and epidemics kill most individuals and leave behind a small, random group of survivors. It may lead to the loss of some alleles and the allele frequencies in new group are very different from the original population. The founder effect occurs when a few individuals move away from the parental population to establish a new colony. The founding individuals of the new colony do not represent the genetic diversity of the parental population as some alleles may be missing altogether.

1. The bottleneck effect in a population will be very pronounced in the following case.
   1. severe fire
   2. mutations in a population
   3. random mixing of individuals
   4. death of some individuals
2. When the allelic frequencies of a population change over generation due to chance events, it is called
   1. gene migration
   2. disruptive selection
   3. artificial selection
   4. genetic drift
3. When a few individuals move away from a parental population to form a new colony, it leads to
   1. Bottleneck effect
   2. Natural selection
   3. Founder's effect
   4. Artificial selection
4. Which of the following statements is true for the Founder's effect?
   1. result of an earthquake
   2. immigration of some individuals
   3. some alleles may not be present at all
   4. random mix of all alleles
5. The new population in a bottleneck effect represents
   1. population with loss of a some alleles
   2. large population with stable allelic frequencies
   3. random population with equal number of two alleles
   4. genetic diversity

Answer 1

1. severe fire
2. genetic drift
3. Founder's effect
4. some alleles may not be present at all
5. population with loss of a some alleles