Question

The bottleneck effect reduces genetic variation because a select group of the original population has left and established a new population.

True
False

Answer 1

@Somy

Answer 2

@Kainui

Answer 3

Population bottlenecks occur when a population’s size is reduced for at least one generation. Because genetic drift acts more quickly to reduce genetic variation in small populations, undergoing a bottleneck can reduce a population’s genetic variation by a lot, even if the bottleneck doesn’t last for very many generations. This is illustrated by the bags of marbles shown below, where, in generation 2, an unusually small draw creates a bottleneck.
Reduced genetic variation means that the population may not be able to adapt to new selection pressures, such as climatic change or a shift in available resources, because the genetic variation that selection would act on may have already drifted out of the population.

Answer 4

so true? @Somy

Answer 5

@Kainui

Answer 6

@Compassionate

Answer 7

i thought it would be false @somy

Answer 8

i too think it would be false
because bottleneck effect seems to deal with same population that has factors that reduce genetic variation in that population which basically decrease the size of population
thats what i got

Answer 9

A bottleneck is an event that drastically reduces the population size of something. It does not have to decrease the genetic variation of the population to do this, but it usually does.

Now, after this occurs the effects of genetic drift can cause large scale changes in the population variation. However, it is not correct to say that a bottleneck speeds up or makes genetic drift act more quickly. Genetic drift is 100% random, it cannot speed-up or slow down.

Example of drift effects on large and small populations:

We have two bags, bag A and B. A has 500 black marbles and 500 white marbles. Bag B has 5 white and 5 black. We reach into the bag and randomly select a marble, then flip a fair coin (again random). If the coin is heads we put the marble back, if it is tails we replace the marble with the opposite color.

So, if we select a marble from each bag, say we happen to get two black marbles, 1 from bag A and 1 from bag B, and we flip our coin and get tails. So, we now have 501 white and 499 black in bag A and 6 white and 4 black in B. In bag B there is a 10% increase in white and 10% decrease in black marbles. In Bag A this incease/decrease is 0.1%.