[_delirium]

Viruses evolve in a way that's very similar to living things (and some scientists consider them living, but that gets into philosophical definitions of life). They have genotypes that can mutate, and some of these mutations find ecological niches where they reproduce better than others, which leads to those genomes reproducing themselves more, i.e. evolution by natural selection. They're taxonomized similarly to living organisms as well, into phyla, orders, families, genera, species, etc.