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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]
Bergmann's rule. Bergmann's rule is an ecogeographical rule that states that, within a broadly distributed taxonomic clade, populations and species of larger size are found in colder environments, while populations and species of smaller size are found in warmer regions. The rule derives from the relationship between size in linear dimensions ...
Allen's rule is an ecogeographical rule formulated by Joel Asaph Allen in 1877, [2][3] broadly stating that animals adapted to cold climates have shorter and thicker limbs and bodily appendages than animals adapted to warm climates. More specifically, it states that the body surface-area-to-volume ratio for homeothermic animals varies with the ...
A few decades later, Atkinson (1994) performed a similar review of temperature effects on body size in ectotherms. His study, which included 92 species of ectotherms ranging from animals and plants to protists and bacteria, concluded that a reduction in temperature resulted in an increase in organism size in 83.5% of cases.
Thermoregulation in animals. In biology, kleptothermy is any form of thermoregulation by which an animal shares in the metabolic thermogenesis of another animal. It may or may not be reciprocal, and occurs in both endotherms and ectotherms. [1] One of its forms is huddling. However, kleptothermy can happen between different species that share ...
Ten species of fossil dinosaurs from five taxonomic groups reveal indices even higher than in mammals, when body size is accounted for, indicating that they were highly active, aerobic animals. Thus high blood flow rate, high blood pressure, a four-chambered heart and sustained aerobic metabolism are all consistent with endothermy .
Females were smaller. Insular dwarfism, a form of phyletic dwarfism, [ 1 ] is the process and condition of large animals evolving or having a reduced body size [ a ] when their population's range is limited to a small environment, primarily islands. This natural process is distinct from the intentional creation of dwarf breeds, called dwarfing.
Thermal ecology is the study of the interactions between temperature and organisms. Such interactions include the effects of temperature on an organism's physiology, behavioral patterns, and relationship with its environment. While being warmer is usually associated with greater fitness, maintaining this level of heat costs a significant amount ...