That’s what evolution is.
Biologists talk about it as change in allele ratios over time. Alleles are the different forms a gene can take. Oversimplified example: green, blue, hazel and brown eyes could all be alleles of one gene. If that gene were to mutate you might get purple eyes. If blue eyes couldn’t see as well and the people with them couldn’t find food, over time there’d be fewer of them. That’s evolution.
Translated, that means adaptions that don’t hurt stay in the population. Adaptations that help, increase.