<P> A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events ( such as earthquakes , floods , fires , disease , or droughts ) or human activities ( such as genocide ) . Such events can reduce the variation in the gene pool of a population ; thereafter , a smaller population , with a correspondingly smaller genetic diversity , remains to pass on genes to future generations of offspring through sexual reproduction . Genetic diversity remains lower , increasing only when gene flow with another population occurs or very slowly increasing with time as random mutations occur . As a consequence of such population size reductions and the loss of genetic variation , the robustness of the population is reduced and its ability to adapt to and survive selecting environmental changes , like climate change or a shift in available resources , is reduced . Alternatively , if by chance survivors of the bottleneck are the individuals with the greatest genetic fitness , the frequency of the fitter genes within the gene pool is increased , while the pool itself is reduced . </P>
<P> A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events ( such as earthquakes , floods , fires , disease , or droughts ) or human activities ( such as genocide ) . Such events can reduce the variation in the gene pool of a population ; thereafter , a smaller population , with a correspondingly smaller genetic diversity , remains to pass on genes to future generations of offspring through sexual reproduction . Genetic diversity remains lower , increasing only when gene flow with another population occurs or very slowly increasing with time as random mutations occur . As a consequence of such population size reductions and the loss of genetic variation , the robustness of the population is reduced and its ability to adapt to and survive selecting environmental changes , like climate change or a shift in available resources , is reduced . Alternatively , if by chance survivors of the bottleneck are the individuals with the greatest genetic fitness , the frequency of the fitter genes within the gene pool is increased , while the pool itself is reduced . </P>
loss of diversity in a reduced population is called
loss of diversity in a reduced population is called
population bottleneck
population bottleneck