00:01
Hello students in this question we have been asked that why genetic drift occurs in small populations and we have been given some options and we have to find out the correct option among them.
00:08
So to solve this question first you need to understand what actually is genetic drift.
00:13
The simple definition of genetic drift is the random change, the random change of gene or allelic frequency in a population by chance.
00:32
So just remember the keyword over here which is by chance.
00:35
That means the random change in frequency occurring by chance is basically referred to as genetic drift.
00:43
It occurs in small population and the reason behind genetic drift is major due to the habitat fragmentation or the natural calamities or any kind of epidemic.
00:55
So any change because of habitat fragmentation or natural calamities or because of occurrence of any epidemic may change the allelic frequency of a small population and this is known as the genetic drift.
01:09
It may be of two different types.
01:11
It may be either founder's effect.
01:14
It can be the founder's effect where sometimes the change in allelic frequency is so different that it leads to the formation of a new species.
01:22
So the allelic frequency changes so differently such that it may lead to the formation of a whole complete different species.
01:32
So a new species is formed due to the change in allelic frequency.
01:36
This is known as found out of effect.
01:38
The other form can be the bottleneck.
01:41
And bottleneck effect, what happens? the sudden change in environment may lead to the change in the size of the population.
01:51
The size of population changes because of the sudden change of environmental conditions around the population.
01:59
And this new population may be genetically different from the original population which the size has changed or the size of the population has changed and when this size of population will recover, it will recover in such a way that that it may lead to the production of a new species.
02:16
Now see our main question was why genetic drift occurs in small population...