âº a gradual process of change and development. âº biology Evolution is the process by which the physical characteristics of types of creatures change over time, new types of creatures develop, and others disappear. (Definition of âevolutionâ from the Cambridge Academic Content Dictionary Â© Cambridge University Press)
You can remember the difference between endotherms and ectotherms if you remember that endo- means inside endo- = inside and ecto- means outside ecto- = outside, so endotherms generate their own heat from within, and ectotherms get their heat from the outside.
This is because heat is synonymous with (the same as) energy. The more energy you have the faster the chemical reaction occurs. In the early mammals being endothermic probably allowed them to be active at night when competing reptiles were forced to rest or be sluggish. Being warm blooded is costly.