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An ectotherm (from the Greek ἐκτός (ektós) "outside" and θερμός (thermós) "heat"), more commonly referred to as a " cold-blooded animal ", [1] is an animal in which internal physiological sources of heat, such as blood, are of relatively small or of quite negligible importance in controlling body temperature. [2]
Elevation of body temperature via metabolic production of heat. Weak or absent metabolic control of a particular body temperature. The first trait distinguishes mesotherms from ectotherms, the second from endotherms. For instance, endotherms, when cold, will generally resort to shivering or metabolizing brown fat to maintain a constant body ...
In 1847, Carl Bergmann published his observations that endothermic body size (i.e. mammals) increased with increasing latitude, commonly known as Bergmann's rule. [9] His rule postulated that selection favored within species individuals with larger body sizes in cooler temperatures because the total heat loss would be diminished through lower surface area to volume ratios. [8]
The Cretaceous–Paleogene (K–Pg) extinction event, [ a ] also known as the Cretaceous–Tertiary(K–T)extinction, [ b ] was the mass extinction of three-quarters of the plant and animal species on Earth [ 2 ][ 3 ] approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs.
e. Reptiles arose about 320 million years ago [1] during the Carboniferous period. Reptiles, in the traditional sense of the term, are defined as animals that have scales or scutes, lay land-based hard-shelled eggs, and possess ectothermic metabolisms. So defined, the group is paraphyletic, excluding endothermic animals like birds that are ...
Physiology of dinosaurs. The physiology of dinosaurs has historically been a controversial subject, particularly their thermoregulation. Recently, many new lines of evidence have been brought to bear on dinosaur physiology generally, including not only metabolic systems and thermoregulation, but on respiratory and cardiovascular systems as well.
t. e. Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature as its own body temperature, thus avoiding the need for internal thermoregulation.
Gigantothermy (sometimes called ectothermic homeothermy or inertial homeothermy) is a phenomenon with significance in biology and paleontology, whereby large, bulky ectothermic animals are more easily able to maintain a constant, relatively high body temperature than smaller animals by virtue of their smaller surface-area-to-volume ratio. [1]