There is a pretty large population of Republicans who don't believe in evolution- case in point, Marjorie Trainwreck Greene stated that she doesn't believe in evolution. The beauty of reality is that it doesn't depend on belief- many a non-believer in Darwinian evolution has fallen to natural selection. Put simply, evolution by means of natural selection is merely the fact that individuals which produce the most offspring that survive to reproduce end up with the most descendants which will produce additional descendants. The forces of nature which result in this increased survivability select the individuals (and populations) which reproduce more, and the genetic makeup of these individuals accumulate in the population. Basically, things which reproduce more, reproduce more... it's a fact.
The significance of this phenomenon is apparent in the news (via Tengrain) that the Delta variant, which is more transmissible than Old School COVID-19, has become the dominant coronavirus strain in the United States. Viruses depend on the cells of other organisms to reproduce, so increased transmissibility is a trait which is selected for by natural forces- it's a clear example of Darwinian evolution in action.
There are a few factors which are at play here- the first is the fact that viruses have very short generations, they reproduce quickly, they accumulate genetic variation quickly, they evolve quickly. Another factor is that each individual infected by a virus is an ecosystem in which viral evolution can take place- more victims, more chances for new variants. In these here United States, people who refuse to socially distance, people who refuse to wear face masks, and people who refuse to be vaccinated (usually the same assholes in all three categories) have elected to become laboratories for the evolution of new COVID strains. For instance, Marjorie Trainwreck Greene, who compared mask mandates to the Holocaust, while refusing to believe in evolution, is unwittingly conducting an experiment in viral evolution. As I noted before, one doesn't have to believe in evolution to be subject to it.
To someone who strives for scientific literacy, this is particularly maddening. That Greene should have a vote in public policy which effects the health of Americans is monstrous. The lambda variant has already evolved, the mu, nu, and omicron variants probably aren't far behind (the kappa variant spilled the water in its head and is powerless)... this pandemic is never going to end at this rate.