1.2 Genetic Drift, Population Bottlenecks, and Founder Effects+
when is genetic drift likely to occur?
after a founder effect or bottleneck effect.
what is genetic drift?
genetic drift describes how the frequency of alleles can change over time due to change events rather than selection pressures.
what does genetic drift tend to cause in variation of populations?
genetic drift tends to decrease the variation within a population. however it tends to increase variation between populations potentially leading to speciation.
what mechanisms are most common to evolution of species?
geographical isolation mechanisms such as the formation of a mountain range, or land masses moving apart due to tectonic activity, are thought to have played a major role in the evolution of species.
what happens to the surviving population after a bottleneck?
if the population increases again to original size, the genetic diversity of the population will be reduced.
what happens first in a population bottleneck?
populations can sometimes be reduced to low numbers by climate change or catastrophic environmental events.
what sort of populations are more susceptible to genetic drift?
small populations. rather than large populations that have a greater buffer.
what is a founder effect?
the founder effect occurs when a small number of individuals emigrate from a population, or become geographically isolated from their original population.
what can have a major effect on the allele frequency of a small population?
the random mating and or death of one or two individuals in a population.
what's happens after bottleneck in a population?
the smaller surviving population is unlikely to contain a representative frequency or range it allele that were a present in the original population.
