Bottlenecks<span> and </span>founder effects<span>. </span>Genetic drift<span> can cause big losses of </span>genetic<span>variation for small populations. Population </span>bottlenecks<span> occur when a population's size is reduced for at least one generation.
A population bottleneck is an event corresponding to the fact that a substantial proportion of the population of a species disappears or is prevented from reproducing. There is a significantly different type of demographic bottleneck called the founder effect, which occurs when a subset of a population is, at least as far as reproduction is concerned, isolated from the main group (it does not disappear The two groups will be independent of each other).
In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals belonging to a larger population.
The unit of evolution is the population. A population consists of organisms of the same species that live in the same area. In terms of evolution, the population is assumed to be a relatively closed group. This means that most mating takes place within the population.
