Question

Explain the difference between natural selection and genetic drift.

Answer 1

Difference between natural selection and genetic drift-

GENETIC DRIFT	NATURAL SELECTION
1. It is a Random process	1. It is a Non random process
2. It Does not occur due to environmental changes.	2. Environment play a crucial role.
3. Non directional	3. Directional
4. Non adaptive evolution	4. Adaptive evolution
5. Important allele may disappear	5. Ends up with the survival of fittest
6. Loss of genetic variation	6. Increase genetic variation
7. Operate on neutral allele	7. Operate on any allele

Explanation of above points-

• Natural selection is a process by which the most adaptive trait for an environment become more common generation after generation and it is not a random process.whereas genetic drift is a Random process, it is random change in the genes,so genetic drift is not an adaptive process, meaning it places no role in making the species more suited to its environment
• Genetic drift , Change in allele frequencies in population due to random sampling of organisms, it more likely occur in small population.in natural selection the more alleles may exist to come about in times of environmental change .
• Natural selection is directed evolution to where the most beneficial genes or traits are more likely to succeed and eventually become predominant., thus natural selection is an adaptive process. Genetic drift does not comprise account an allele's adaptive value to a population, and it can result in loss of a beneficial allele or fixation of a harmful allele in a population.
• Natural selection is the process where by traits that confer the highest relative reproductive success (greatest relative Fitness) on their bearers and which can be passed down across generations,increase in frequency over many generations.thus in natural selection Increase genetic variation can occur, but in genetic drift the rate of fixation of alleles is inversely proportional to the size of the population.thus in a small population, genetic variation or drift decrease more rapidly than in the case of larger Population or in natural selection.
• Genetic drift may cause gene variants to abandon or disappear completely and thereby cut down or reduce genetic variation. where natural selection ends up with survival of fittest.
• In genetic drift, there is a small population then chance could determine whether a neutral allele becomes extinct or increases in frequency to fixation.where Natural selection appear when individuals with certain genotypes are more expected than individuals with other genotypes to survive and reproduce, and pass on their alleles to the next generation, thus natural selection operates on any allele.