In which scenario would a species be less likely to adapt effectively to environmental changes?

A species is less likely to adapt effectively to environmental changes when it has low genetic diversity within the species. Genetic diversity refers to the variety of genetic traits within a population. A population with low genetic diversity has a limited gene pool, which reduces the range of traits available for natural selection to act upon. This lack of variety means that if environmental changes occur, the chances of some individuals within the species possessing the necessary traits to survive and reproduce under the new conditions are significantly diminished.

In contrast, high genetic variation provides a broader range of traits that can help some individuals adapt to changing environments. Isolation from other species can limit gene flow, but it does not inherently mean a species can't adapt as long as it has genetic variation. Frequent mutations can introduce new traits into a population, which may facilitate adaptation, especially if those mutations are beneficial. Thus, low genetic diversity directly correlates with a reduced potential for adaptation to new environmental challenges.