There's a well known allegory that states that if a frog is dropped in boiling water, jumps out immediately and avoids a brothy grave; yet a frog placed in cold water that is heated slowly enough you'll have some tender (tasty?) froggy sous vide.
Recent research suggests that if the temperature of that pot (or the world as a whole, you guys following me?) increases slowly enough the increasing temperature could actually lead to increased biodiversity. Little froggy might evolve a physiology better adapted to warmer temperatures.
Maybe frogs would evolve something similar to sweat glands or dragon wings (because that would be sweet... and there would be increased surface area for heat radiation, of course).
Somewhat related: did you all hear about the frog with the transparent belly?