Who cares what the definition is? We as humans learn to adapt to our land and cope just like fishes developed lungs to breathe on land. To cope with where they were being forced to move to... evolution kicked in and slowly had them develop a lung that could work on land. But it's still them adapting to the change. Even the predators adapted so that they could once again prey on the fishies. It's all the same thing... you're just taking one thing and calling it something else.