The random changes in gene frequencies in a population occurring by chance alone rather than by natural selection are called genetic drift or the Sewall Wright effect. The effects of genetic drift are mostly visible in tiny isolated populations, although it occurs in all people.
Important Notes on Genetic Drift
List - I | List – II | ||
A. | Living Fossil | i. | Elongated canine teeth |
B. | Connecting Link | ii. | Vermiform appendix |
C. | Vestigial Organ | iii. | Echidna |
D. | Atavism | iv. | Latimeria |
List-I | List-II | ||
(A) | 1 mol of H2O to O2 | (I) | 3F |
(B) | 1 mol of MnO-4 to Mn2+ | (II) | 2F |
(C) | 1.5 mol of Ca from molten CaCl2 | (III) | 1F |
(D) | 1 mol of FeO to Fe2O3 | (IV) | 5F |
In the given figure, which component has thin outer walls and highly thickened inner walls?
Evolution is a process that occurs in changes in the genetic content of a population over time. Evolutionary change is generally classified into two: microevolution and macroevolution. The process of changes in allele frequencies in a population over time is a microevolutionary process. Three main mechanisms that cause allele frequency change are natural selection, genetic drift, and gene flow. On the other hand, macroevolution refers to change at or above the level of the species.