Of course how well an animal digests the food it is eating affects its survival and the survival of its offspring? If your tribe of anatomically modern homo sa

Of course how well an animal digests the food it is eating affects its survival and the survival of its offspring? If your tribe of anatomically modern homo sapiens sapiens moves to the sea shore for a thousand years because environmental changes have made your previous lifestyle impossible, mutations that correlate with shelf fish allergies are going to be highly disadvantageous, for instance. If wheat farming is all the rage, anyone who can digest gluten is going to have way more offspring than anyone who can't.