As others have said, evolution doesn’t really work that way: an individual organism doesn’t make changes to suit its environment. Offspring aren’t carbon copies of their parents, there’s variation of pretty much every attribute. Most attributes don’t really impact survivability, but sometimes they do. If certain things tend to result in an organism surviving to reproduce better than other things, those traits get reinforced and are more likely to be passed on. Over lots and lots of generations, you can end up with pretty much every organism in that species having that trait, and that trait getting more and more pronounced.