Question

Match the following.

List-I	List-II
(A) Founder effect	(I) Long necked giraffes
(B) Bottleneck effect	(II) Heterozygous for sickle cell anaemia
(C) Genetic load	(Ill) Pitcairn Island human population
(D) Directional selection	(IV) Polydactylic dwarf individuals
	(V) Sunflower population in california

• A. A- (II), B- (I), C- (III), D- (IV)
• B. A- (V), B- (IV), C- (II), D- (III)
• C. A- (III), B- (IV), C- (II), D- (I)
• D. A- (IV), B- (II), C- (V), D- (III)

Answer 1

The correct option is C A- (III), B- (IV), C- (II), D- (I)

• Founder effect is one form of genetic drift which is the derivation of a new population from a small isolated group of individauls (founders) that is genetically different from the parent populations. Ex. Pitcairn island human population. So, A matches with (III).
• Bottleneck effect is a form of genentic drift. Bottlenecks are the natural calamaties like earthquakes, volcanoes etc. After the bottlenecks, the parents of the next generation have been reduced to a small number that are left under bottlenecks. Eg., Polydactylic dwarf individuals are more in Old Order Amish population of Lancaster in USA. This phenotype is a recessive type. So, B matches with (IV).
• The deleterious genes that produce a genetic load may arise from mutation or from genes that are favorable in heterozygotes but not in homozygotes. So, C matches with (II).
• Directional selection is a mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time towards that phenotype.
• The neck of the giraffe was small. There was a selection pressure against short necks since individuals with short necks could not reach as many leaves to feed on. As a result, the distribution of neck length shifted to favor individuals with long necks. So, D matches with (I).

Thus, the correct answer is option (C).