Organisms that can tolerate and thrive in a wide range of temperatures are termed

Organisms that can tolerate and thrive in a wide range of temperatures are called eurythermal organisms (e.g., humans, red algae, Artemisia tridentata of family Asteraceae). Stenothermal organisms are restricted to a narrow range of temperatures (e.g., corals, fishes, polar bears, conifers, coconut plants). Poikilothermic (cold-blooded) organisms are those which cannot maintain a constant body temperature. Thermoconformers are  the organisms whose body temperature changes according to the external temperature.