Final answer:
Population bottlenecks increase the risk of extinction by reducing genetic variation and limiting adaptability to changing environments.
Step-by-step explanation:
The population bottleneck effect refers to a dramatic reduction in the size of a population, resulting in the loss of genetic variation. This loss of genetic diversity increases the risk of extinction for the affected population. With fewer individuals and decreased genetic variation, the population becomes more vulnerable to environmental changes and is less able to adapt to new conditions.
For example, imagine a population of birds that undergoes a population bottleneck event, such as a severe storm that kills off a large number of individuals. The surviving birds may not represent the full range of genetic variation that was present in the original population. This means that the population as a whole has a reduced ability to adapt to changes in their environment, such as a new predator or a decrease in food availability.In summary, population bottlenecks increase the risk of extinction by reducing genetic variation and limiting the adaptability of a population to changing environments.