EVERYDAY SCIENCE

Detailed explanation-1: -ectotherm, any so-called cold-blooded animal-that is, any animal whose regulation of body temperature depends on external sources, such as sunlight or a heated rock surface. The ectotherms include the fishes, amphibians, reptiles, and invertebrates.

Detailed explanation-2: -Ectotherms depend mainly on external heat sources, and their body temperature changes with the temperature of the environment.

Detailed explanation-3: -Unlike homeothermic animals like mammals and birds, they are unable to regulate their body temperature internally. Their body temperature depends directly on the external surroundings. They can control their body temperature only by moving to an environment with a suitable ambient temperature.

Detailed explanation-4: -In a table compiled by Rogers (’27, p. 353), the results of several investigators show that the body temperature of a fish may vary between 9.3°F. above (Broussonet) and 2.8°F. below (Davy) the temperature of the water.

Detailed explanation-5: -Lizards (Tiliqua scincoides) regulated their internal body temperature by moving back and forth between 15 degrees and 45 degrees C environments to maintain colonic and brain temperatures between 30 degrees and 37 degrees C.