Final answer:
When an endangered population rebounds with less genetic variation, this is often due to a bottleneck effect resulting from a small initial population size. The reduced genetic diversity may increase susceptibility to diseases and limit adaptability, but conservation efforts aim to increase the population's genetic variance.
Step-by-step explanation:
When a population that was once endangered experiences a population boom but ends up with less genetic variation, several biological concepts are at play. This scenario often involves a small initial population size that survives a bottleneck event, which is a major reduction in population size due to natural or human-caused disasters such as earthquakes or habitat destruction. After the bottleneck, the surviving population's genetic structure may lack diversity.
The reduction in genetic diversity can increase vulnerability to recessive lethal alleles, potentially leading to genetic diseases, or may limit the ability to adapt to changing environmental conditions. Moreover, events like these might result in habitat isolation, where a population becomes reproductively and genetically independent, leading to further loss of genetic diversity as only a small range of genetic material is passed on to future generations.
Conservation efforts may aim to eliminate the threats to endangered species, and successful recovery can involve enhancing genetic variance to mitigate issues such as inbreeding depression. This is crucial because inbreeding can bring together deleterious recessive mutations, increasing the likelihood of genetic disorders within a population.