What is a downside of low genetic diversity in a species?

Low genetic diversity in a species is a significant concern because it increases susceptibility to extinction. This occurs for several reasons. When a population has low genetic diversity, it means that there is a limited gene pool, which reduces the range of traits available for selection by natural processes. This can hinder the ability of a species to adapt to changing environmental conditions, such as climate change, habitat destruction, or the emergence of new diseases.

Additionally, with a homogenous genetic makeup, a population may be more vulnerable to pathogens. If a disease strikes, for instance, a lack of genetic variation means there may not be individuals with resistance to that disease, potentially leading to widespread mortality and decline in population numbers. Such vulnerabilities can compound over time, making recovery from population declines more difficult and increasing the likelihood of extinction.

In contrast to the other options, which suggest either positive outcomes associated with low genetic diversity or misunderstand the nature of competition and adaptation, low genetic diversity unequivocally threatens the long-term survival of a species.