Hey Hrikhikesh....understand easily...1. ..Founder Effect is an important example of genetic drift in human population. It is noted when a small group of persons called Founders, leave their homes to find a new settlement, the population in a new settlement may have different genotype frequencies from that of the parent population. Formation of a different genotype in a new settlement is called founder effect.sometimes they have a new species.
2...Genetic drift is drastic change in allele frequency when the population size becomes very small. Therefore, it alters the gene frequency of remaining population which causes variation. It is named after the American geneticist Sewall Wright who realised its evolutionary significance. Although genetic drift occurs in all populations, its effects are most marked in very small isolated population. Two important examples of genetic drift are founder effect and bottleneck effect. Genetic drift is called also Swewall Wright effect.