Final answer:
The bottleneck effect is the term used to describe the significant loss of genetic variation that occurs when a population is suddenly reduced in size due to a random event such as habitat loss, natural disaster, or other environmental changes. It results in a decreased gene pool and increased susceptibility to further environmental changes.
Step-by-step explanation:
When a population's size is dramatically reduced due to habitat loss, natural disaster, or other environmental changes, this can lead to a significant impact on the population's genetic variation. This genetic impact is known as the bottleneck effect.
The bottleneck effect occurs when a large portion of a population is suddenly eliminated due to a random, non-selective event, such as a hurricane, earthquake, or wildfire. Consequently, the genetic structure of the surviving population may greatly differ from that of the original population, because the survivors' genetics become representative of the entire population. The evolutionary consequence of the bottleneck effect is a reduction in genetic variability, which can make a population more susceptible to other environmental changes and may affect the population's future adaptability.
Another similar concept related to genetic drift is the founder effect, which happens when a new population is established by a small number of individuals from a larger population. This can result in a new population with reduced genetic variation compared to the original population.