Question

If an organisms fails to adapt to it's environment, what could be the possible consequences?

Answer 1

Evolution of species over a long duration happens due to adaptive learning of organisms in new environments.  If the organism is flexible in different physiological environments, it will evolve.  The metabolic processes change according the environment to an extent.  Like breathing at a high altitude when Oxygen content is less.

But if the organism fails to adapt under severe conditions, that organism will die and the species will become extinct.