According to the theory of natural selection, a species that lacks the variations necessary to adapt to a changing environment will most likely go extinct.

Here's why:

* Natural Selection: The core of this theory is that individuals with traits better suited to their environment are more likely to survive, reproduce, and pass on those advantageous traits.

* Variations: Variations within a population are essential for natural selection to work. These variations arise from random mutations in genes.

* Adaptation: If a species lacks the necessary variations, it cannot develop adaptations that help it cope with environmental changes (like climate change, new predators, or changes in food sources).

* Lack of Adaptation = Extinction: Without the ability to adapt, the species will struggle to survive and reproduce. Over time, the population will decline and eventually go extinct.

In other words, natural selection favors those who can adapt, and those who can't adapt will likely be eliminated.