I have a question about genetic drift...wat is it actually...the book said that it random change in allele frequency but how does that happen???

and wats a founder effect?

Genetic drift refers to the random changes in the frequency of different alleles (variations of genes) in a population over time. It is one of the mechanisms of evolution. Genetic drift occurs when random events cause certain alleles to become more or less common in a population, independent of their effect on the organism's fitness.

There are two main ways by which genetic drift can occur:

1. Population Bottlenecks: A population bottleneck is an event that drastically reduces the size of a population, such as a natural disaster or disease outbreak. As a result, the surviving individuals may have a different allele frequency than the original population, purely due to chance. This can lead to the loss of certain alleles or the fixation of others.

2. Founder Effect: The founder effect occurs when a small group of individuals establishes a new population in a different geographic area or becomes isolated from the larger population. Since the founding group is a small subset of the original population, their allele frequencies may differ significantly from the source population's. This introduces a random change in allele frequencies in the new population.

To give you an example of the founder effect, let's say a small group of birds migrates to a new island. The genetic makeup of these birds is now a representation of the genetic diversity of the founding individuals. If they have a different allele frequency for certain traits, this can persist in future generations, leading to unique characteristics in the island's bird population.

In summary, genetic drift is the random change in allele frequency in a population. It can occur through population bottlenecks or the founding of new populations, as in the case of the founder effect. These random events can cause certain alleles to become more or less common over time, independent of their direct effect on an organism's survival or reproductive success.