Species are usually drawn as single units, but look closely and many of them are patchworks. Populations living in different conditions, a windswept ridge here and a sheltered valley there, can differ in ways that matter for survival while still interbreeding freely. These local variants are called ecotypes, and they are turning out to be one of the most interesting places to watch evolution happen.
What makes ecotypes useful is that the differences are often encoded in large stretches of rearranged DNA, regions where chromosomes have flipped or fused so that whole sets of genes travel together. That arrangement keeps beneficial combinations intact, allowing a population to adapt to a local habitat without splitting into a new species.
The concept is more than academic bookkeeping. Ecotypes preserve genetic variation that a species may need as conditions change, and they can be lost when habitats are fragmented. Recognising them changes how conservationists think about what exactly they are trying to protect.
