Final answer:
Populations with reduced genetic diversity due to population bottlenecks are more vulnerable to extinction as natural disasters can lead to a severe reduction in genetic variation, increased inbreeding, and reduced adaptability.
Step-by-step explanation:
Populations with reduced genetic diversity, such as those affected by population bottlenecks, are at an increased risk of extinction for several reasons. When a natural disaster like an earthquake or hurricane occurs, it can randomly kill a large portion of the population, resulting in what is known as the bottleneck effect. This effect means that the genetic makeup of the survivors will drastically differ from the original population's makeup.
Fewer individuals in a population means that genetic variation is low. This reduced genetic diversity can lead to inbreeding depression, making the population more susceptible to diseases, as well as less adaptable to changes in the environment. Additionally, a small initial population size means that harmful recessive alleles may become more common, potentially leading to a decrease in population vitality and an increased chance of extinction.
The bottleneck effect can be especially magnified by events that kill individuals randomly, without regard for their genetic traits. This reduction in genetic variation can make it difficult for a population to recover from environmental changes or disease outbreaks.