Endothermy in different species

Endothermy in different species

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Birds and mammals are both endothermic, meaning they metabolically generate the heat they need to keep their body within a certain temperature ranger.

But birds are closer relatives to reptiles than they are to mammals, and reptiles are not endothermic. Thus birds and mammals developed endothermy independently; and here is the question:

How does thermal regulation differ in birds and mammals?

This is in between a comment and an answer…


  1. reptiles can have several definitions. Some of them causing birds to be a reptile.
  2. You probably meant "evolved" instead of "developed".

  3. Thermoregulation is performed by a set of different mechanisms and it is plausible that your question would be considered as too broad. Note however that I am NOT a physiologist and might overestimate the scope of the question.

Similitudes between birds and mammals

From wikipedia (here)

In cold environments, birds and mammals employ the following adaptations and strategies to minimize heat loss:

  • Using small smooth muscles (arrector pili in mammals), which are attached to feather or hair shafts; this distorts the surface of the skin making feather/hair shaft stand erect (called goose bumps or pimples) which slows the movement of air across the skin and minimizes heat loss.
  • Increasing body size to more easily maintain core body temperature (warm-blooded animals in cold climates tend to be larger than similar species in warmer climates (see Bergmann's Rule))
  • Having the ability to store energy as fat for metabolism
  • Have shortened extremities
  • Have countercurrent blood flow in extremities - this is where the warm arterial blood travelling to the limb passes the cooler venous blood from the limb and heat is exchanged warming the venous blood and cooling the arterial (e.g., Arctic wolf[3] or penguins[4][5])

In warm environments, birds and mammals employ the following adaptations and strategies to maximize heat loss:

Behavioural adaptations like living in burrows during the day and being nocturnal

  • Evaporative cooling by perspiration and panting
  • Storing fat reserves in one place (e.g., camel's hump) to avoid its insulating effect
  • Elongated, often vascularized extremities to conduct body heat to the air


Warm-blooded is an informal term referring to animal species which can maintain a body temperature higher than their environment. In particular, homeothermic species maintain a stable body temperature by regulating metabolic processes. The only known living homeotherms are birds and mammals, though ichthyosaurs, pterosaurs, plesiosaurs and non-avian dinosaurs are believed to have been homeotherms. Other species have various degrees of thermoregulation.

Animal body temperature control varies by species, so the terms "warm-blooded" and "cold-blooded" (though still in everyday use) suggest a false idea of there being only two categories of body temperature control, and are no longer used scientifically.


Jeffrey B. Graham , . Carl Gans , in Amniote Origins , 1997

Metabolic Rate

A significant event in tetrapod ecological physiology was the evolution of endothermy ( Bennett, 1991 Ruben, 1995 ), and biologists have long pondered the how, why, when, and where of this metabolically important specialization. More than any other vertebrate specialization, endothermy has dramatically altered the energetic balance sheet for vertebrates. The standard metabolic rate of ectotherms is about an order of magnitude less than the basal metabolic rate of mammals ( Withers, 1992 ). Endothermy also affects routine activity levels, stamina, and endurance. Bennett and Ruben (1986) have reviewed the numerous hypotheses forwarded regarding the fossil evidence for the acquisition of endothermy in mammals. Ruben (1995) has also reviewed the physiological and metabolic bases for endothermy. The large sails of Dimetrodon (from the Lower Permian) and other sphenacodontids suggest the presence of a complex behavioral repertoire revolving around the capacity to regulate heat transfer ( Romer, 1948 Haack, 1986 Tracy et al., 1986) . The discovery of turbinate bones in the nasal passages of therapsids indicates the presence of a water-conserving mechanism linked to frequent ventilation and endothermy and correspondingly suggests that the evolution of a “mammalian” metabolic rate had occurred by the Late Permian ( Hillenius, 1992 1994 ).

We suggest a two-part scenario for the evolution of a mammalian-level of metabolism in the hyperoxic Carboniferous-Permian biosphere. First, based on the discussions of Bennett and Ruben (1986) , Carroll (1986) , Tracy et al (1986) , and others, synapsids may have undergone natural selection for a relatively high metabolic rate and also increased their body size (thermal inertia). The sensory and locomotor specializations of these synapsids, as well as their capacities for rapid digestion and assimilation could all have been enhanced. Increased metabolic expenditures such as these, although necessitating a greater rate of energy resource acquisition, would have been favored by an abundance of environmental oxygen. Second, the presence of these metabolically specialized and hyperoxia adapted organisms in a Permian environment characterized by progressive atmospheric hypoxia could have intensified natural selection on certain lineages for an increased ventilation frequency (hence the appearance of turbinal bones in therapsids) and improved cardiac efficiency for oxygen delivery to the tissues (i.e., separation of systemic and pulmonary circulation).

Thermoregulation in Animals: Some Fundamentals of Thermal Biology☆

Evolutionary Considerations

This already leads to the question of phylogenetic development of thermoregulation. In order to understand this tradition, it may be helpful to look at some taxa that are somewhere in between ecto- and endothermy. Some insects, for example, large, nocturnal moths (Sphingidae), bees, dragonflies or wasps, are able to regulate thoracic and in some cases also abdominal temperature. However, this endothermy is only achieved when they are active, they perform wing-movements, called shivering, decoupled from flight. Moths at least, due to their hairy scales, have values of thermal conductance similar to birds and mammals, and they can keep large differences between Ta and Tb (some North American moths can fly at a core body temperature of around 30°C at Ta = 0°C). However, these small animals cannot achieve continuous endothermy similar to same-sized vertebrates if they are not active day and night (which insects are not).

Larger species in the continuum between ecto- and endothermy are found among fish. Bluefin tuna (Thunnus thymnus) of 200–350 kg can uphold temperature differences of up to 20°C. In these fish, contrary to “cold- bodied” species, we find large amounts of red (= aerobic) skeletal muscles near the body core (along the vertebral column) instead of under the skin. Also a high BMR, and a countercurrent heat-exchanger in the circulatory system are further characteristics of these endothermic fish. Besides red skeletal muscles, endothermic fish also have local heat sources in stomach, gut and liver tissue. Also (again kept up by retia mirabilia = countercurrent heat exchangers) in the eyes and the brain of warm-blooded fish such as Mako sharks (Isurus oxyrhynchus) there is a temperature difference to the environment of > 5°C. However, there are no heat generating tissues in the sharks, heads, instead warm blood from abdominal red muscles is transported directly to the eye and brain regions. In some bony fish (e.g., Swordfish, Xiphias gladius) contrary to sharks, eye muscles are working as local heat sources, the whole complex of heater muscles, brain and eyes is thickly isolated in fat, and temperature differences of up to 14°C can be upheld between brain and surrounding water.

There is also evidence for mechanisms of physiological and behavioral temperature control in these fish. Also some python snakes and Leatherback turtles (Dermochelys coriacea) are able to obtain a certain control over their body temperatures.

Thus, the question of when and why endothermy could evolve has to be approached very broadly. The adaptive value of real endothermy and effective thermoregulation could have been to allow a decrease in body size at a constant body temperature. This would not only have allowed an increase in activity, but also an increase in reproduction. However, endothermy also is costly, and thus certain preconditions had to be met before achieving it. On the biochemical level, changes in membrane permeability for ions, are discussed as necessary preconditions for increasing metabolic rates. On the organismic level, it seems plausible at least in the evolution of mammals to assume that the large (up to 250 kg) therosaurus reptiles, the ancestors of mammals, had, due to their large size, achieved a certain degree of thermal independence, and that a whole array of morphological and physiological changes (development of isolating fur, increasing efficiency of ventilation by developing a bony palate and diaphragm, etc.) then allowed the transition from large reptile (with so called inertial homeothermy, which means they simply were too large to lose enough heat for being poikilotherms) to small mammal with an active, regulatory endothermy.

Ectothermy and endothermy: evolutionary perspectives of thermoprotection by HSPs

Living organisms respond to heat exposure by selectively expressing heat shock proteins (HSPs). Accumulation of HSPs confers thermotolerance in cell cultures and in ectotherms and is an important component of the heat shock response. This response, however, has not been directly examined in relation to different thermal states', namely ectothermy vs endothermy. By using avian development as a model system for transition from ectothermy to endothermy, we show that, in contrast to the ectothermic state, in the endothermic state the organism is more resistant to heat but relies less on HSPs as a first-line thermoprotective mechanism. Moreover, intraspecific, real-time, in vivo measurements in genetically diverse fowl strains relate improvement of thermoresistance in endotherms to improved body temperature (Tb) regulation, with a concomitant delay in the expression of HSPs. The time course of this delay and the Tb at which it occurs imply that the ontogenetic and evolutionary pathways leading to improved thermoresistance may have followed two, apparently non-related, parallel routes--cellular and peripheral (non-cellular). In search of other cellular components that differentially participate in the heat shock response, we revealed a significant expression of fatty acid synthase (FAS) in heat-exposed endotherms but not in ectotherms.

Development of endothermy in birds: patterns and mechanisms

Endothermy is a conspicuous and important adaptation in birds. Even though juvenile and adult birds are endothermic and maintain a constant, high body temperature by means of internal heat production, they begin life expressing an ectothermic phenotype. Depending on where a species falls along a continuum of maturity at hatching, from precocial to altricial, they begin to express endothermic traits either close to the time of hatching or as nestlings over a period of 1–3 weeks. Developing endothermy requires attaining a high basal metabolic rate and associated aerobic scope to produce sufficient internal heat, insulation to retain the internally produced heat, and a thermostat that “turns on” heat production in response to cooling ambient temperatures. To support the high metabolic costs of endothermy, the animal must have the capacity to deliver sufficient oxygen and nutrients to the heat-generating tissues. In this review, we examine the development of physiological and morphological traits that are required for endothermy and discuss their potential to limit the development of endothermy. These include ventilatory and cardiovascular function, contribution of visceral organ masses, membrane lipid composition, substrate supply pathways, and skeletal muscle physiology. The developmental trajectories of each of these systems in precocial and altricial species can have significant effects on the development of an endothermic phenotype.

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Interfacing our knowledge of thermal physiology with current and projected future climates enables us to address the potential impacts of climate change, and increased temperatures in particular, on organisms. We have highlighted the contrasting effects of increased temperatures on the potential activity times and energy needs of ectotherms and endotherms, two direct outcomes of their different physiology that critically affect their broad-scale ecology. Climate change may increase the potential activity time of temperate ectotherm species in the tropics it may reduce potential activity time during the reproductive season while also increasing maintenance costs ( Huey et al., 2009 Kearney et al., 2009 Dillon et al., 2010 ). The most severe consequences for ectotherms may arise from high temperatures causing overheating or unsustainably short potential activity times due to heat avoidance ( Kearney et al., 2009 Sinervo et al., 2010 ). Latitudinal gradients in thermal breadth suggest greater biological impacts in the tropics than in temperate zones ( Deutsch et al., 2008 Huey et al., 2009 ).

A recent model of thermal limits on activity time, which was validated for Mexican lizards and applied globally, suggests that reduced activity time due to climate change may result in substantial extinctions ( Sinervo et al., 2010 ). As yet, similar field demonstrations of increased heat per se causing widespread die-offs or fatally limiting foraging activity of populations are not available for endotherms. Low-latitude endotherms tend to have higher body and critical temperatures than ectotherms and may thus be more buffered in their activity and energy requirements. Nevertheless, short-term population declines in response to extreme heat events have been demonstrated (e.g. in European birds) and have been linked to indirect estimates of thermal tolerance ( Jiguet et al., 2006 ).

A particular concern in endotherm arid specialists, which lack easy access to water, is increasing evaporative water loss in the face of increased intensity and frequency of heat events. Projections for hot days in example desert locations suggest that water needs by 2080 could increase by 95% for small-bodied (5 g) and 65% for medium-bodied (50 g) birds, leading to dramatically reduced survival times ( McKechnie & Wolf, 2009 ). At least in arid environments, water loss rather than overheating is likely to be the main constraint on endotherm activity and survival in a future warmer world.

There is a growing focus on using organismal physiology to predict the responses of vertebrate ectotherms to climate change, ranging from approaches that are specific and complex ( Kearney & Porter, 2009 Buckley et al., 2010 ) to those that generalize physiological constraints ( Deutsch et al., 2008 Kearney et al., 2009 Sinervo et al., 2010 ). For endotherms, biophysical models for a few species ( Porter et al., 2002 ) and some broader generalizations in the context of climate change ( McKechnie & Wolf, 2009 Monahan, 2009 ) have been developed, but predictive models have lagged due to the more complex link between environmental temperatures and fitness in endotherms ( La Sorte & Jetz, 2010 ). Yet the stark ecophysiological contrast between ectotherms and endotherms already points to the importance of considering physiology in predicting species responses to climate change.


Typical endothermic temperature physiology of mammals is characterized by four measurable aspects:

The basal or resting metabolic rate (BMR) is high. It varies typically from five to as much as ten times that of an ectotherm of similar body size (e.g. Hayes & Garland, 1995 Hulbert & Else, 2000).

The body temperature (Tb) is higher than the animal’s normal ambient temperature, and lies between about 28 °C and about 40 °C depending on species (e.g. Crompton, Taylor & Jagger, 1978 Eisenberg, 1981).

The core body temperature is maintained at a remarkably constant value, not normally varying by more than 1–2 °C over the 24-h diurnal cycle (e.g. Eisenberg, 1981).

The maximum aerobic metabolic rate (MAMR) that the organism is capable of sustaining is greatly elevated over that of ectotherms. There is a very approximately constant ratio of 10–15 between the basal rate and the maximum aerobic rate in amniotes, and therefore, like the BMR, the MAMR of an endotherm is typically somewhere between five and ten times that of an ectotherm of similar body size (e.g. Taylor et al., 1987 Hinds et al., 1992 Hayes & Garland, 1995).

Disentangling which of these aspects are the functions and which are the mechanisms responsible for the functions seems clear now, although for many decades there was considerable confusion. The elevated BMR cannot be considered to be of direct functional importance because it is very variable among otherwise similar and closely related species. To name but one of many examples, the study of Shkolnik (1980) showed that the desert-adapted African hedgehog Paraechinus aethiopicus has a BMR only half, and the semi-arid adapted Hemiechinus auritus only three-quarters that of the temperate-adapted European hedgehog Erinaceus europeaus, yet all maintain the same body temperature of 34 °C, and have similar activity levels. The elevated body temperature also cannot be regarded as an adaptation per se, because it too is very variable among otherwise comparable mammal species, and because many ectothermic amniotes operate with body temperatures as high as, or higher than, those of mammals. This leaves two basic direct functions of the endothermic physiological system, thermoregulation and elevated aerobic activity levels, respectively.


Maintaining a constant body temperature is an ecological adaptation for remaining active over a wider range of ambient temperature. Although in principle this includes high ambient temperatures, the effect is perhaps more striking at the low ambient temperature of night-time. Thermoregulation also serves another, distinctly physiological function. Maintenance of a precisely constant internal temperature is an essential prerequisite for the higher degree of organizational complexity of endotherms compared with ectotherms. The rates of enzyme-controlled metabolic pathways, diffusion rates such as that of transmitter molecules across synapses, and the viscosity and therefore speed of contraction of muscle fibres such as the heart muscle are all temperature dependent, and therefore can only occur at the reliably predictable rates necessary for sustaining the integrity of a complex system if the body temperature is maintained constant. Given the degree of sensitivity of the greatly enlarged and complex mammalian brain to induced temperature changes, it is evident that the central nervous system more than anything depends critically for its proper functioning on maintenance of the correct temperature.

As recently reviewed in the context of the origin of avian endothermy ( Schweitzer & Marshall, 2001), the biochemical basis for the elevated BMR lies in an increased number of mitochondria in the cells, mostly those of the visceral organs. They metabolize aerobically and inefficiently, with a consequent increase in heat production ( Hulbert & Else, 1989, 1990, 2000). For this to be linked efficiently to a thermoregulatory function requires first that the body is sufficiently well insulated for the body temperature to rise high enough to create a heat gradient between the body and the outside world: the surface conductance has to be low enough. But secondly, there must be a means of varying the conductance of the surface with great speed and precision so that the rate of heat loss can be rapidly adjusted to changes in the net rate of heat input, which is the sum of the BMR and any heat of activity being generated by muscular exercise. Variable insulation of the skin by variable piloerection, variable blood flow through the cutaneous capillaries and variable posture are the well-known mechanisms for achieving this rapidly adjustable rate of conductance of heat from the body. Many other features such as a more effective circulatory system for heat distribution and a higher oxygen-carrying capacity of the haemoglobin are also necessary, as will be discussed later.


Within the thermo-neutral zone of ambient temperature, much the greater proportion of the additional metabolism above BMR is devoted to muscular activity, and therefore the five-fold or more increase in the maximum sustainable level of aerobic metabolism in endotherms potentially impacts on all the activities of the animal. For example, Bennett & Ruben (1979) quoted a maximum sustainable speed of a 1-kg Iguana as 0.5 km h −1 and of a mammal of similar body weight as 4.1 km h −1 Farmer (2000) quoted the huge daily locomotory investment in birds foraging for their nestlings. The mechanism behind the raised MAMR is quite simple. A larger number of mitochondria with a larger net membrane area in the muscle tissue, coupled with adequate oxygen delivery by the vascular system, permits a greater rate of ATP synthesis and its conversion to mechanical energy.

The relationship between the increased level of maximum aerobic activity and the thermoregulatory function is poorly understood: the main site of metabolism for thermoregulation is the viscera, that for aerobic activity is the musculature, but there is no obvious mechanical or functional reason why they should be linked to one another ( Bennett & Ruben, 1979). Nevertheless, a considerable body of empirical evidence in living organisms demonstrates the roughly constant ratio between the two values in both ectotherms and endotherms (e.g. Bennett & Ruben, 1979 Hayes & Garland, 1995 Ruben, 1995 Krosniunas & Gerstner, 2003). Suggestions of possible reasons for the correlation include: a relationship between an increase in the metabolic activity of the muscle tissue and a corresponding increase in the metabolic functions of the viscera necessary to maintain the muscle tissue ( Ruben, 1995) a coincidental correlation between a raised BMR for maintaining a higher incubation temperature for the juvenile and an increased need for higher muscle activity levels associated with food collection for provisioning the young ( Farmer, 2000) a correlation between increased locomotory activity for food collecting and increased visceral metabolism for assimilation of the extra food ( Koteja, 2000) and a requirement that the BMR remains a constant fraction of the MAMR in order to maintain a rapidly increased oxygen supply via the circulatory system during high activity levels ( Krosniunas & Gerstner, 2003). This problem will be returned to.

Opah (Lampris guttatus): First Known Warm-Blooded Fish Species

A team of researchers led by Dr Nicholas Wegner of NOAA Fisheries’ Southwest Fisheries Science Center has discovered a whole-body form of endothermy in a deep-water fish, the opah (Lampris guttatus), that produces heat through the flapping of wing-like fins and minimizes heat loss through a series of counter-current heat exchangers within its gills. Unlike other fish, opah distribute warmed blood throughout the body, including to the heart, enhancing physiological performance while foraging in the cold waters.

The opah (Lampris guttatus). Image credit: NOAA Fisheries / Southwest Fisheries Science Center.

The opah, also known as the spotted moonfish, cravo, kingfish, and Jerusalem haddock, is a deep-bodied, compressed fish found in eastern North Atlantic, North Sea and Mediterranean.

Opah have beautiful coloration: the body is a steely blue grading to rosy on the belly, with white spots covering the flanks. The body is covered in very small, smooth scales.

Both the median and paired fins are a bright vermillion, contrasting strongly with the body. The large eyes stand out as well, ringed with golden yellow. The mouth is small and toothless.

Opah grow to over 5 feet (1.5 meters) in length and can weigh over 150 pounds (70 kg).

They are apparently solitary but are known to school with tuna and billfish. They propel themselves by flapping their pectoral fins. This, together with their forked caudal fins and depressible median fins, indicates that opah, like tuna, maintain themselves at constantly high speeds.

They regularly dive to depths below 650 feet (200 meters) where they feed on mesopelagic fishes, squids and crustaceans – and where water temperatures are below 4 degrees Celsius. Primary predators of opah are Mako and Great White sharks.

Fish that typically inhabit cold depths tend to be slow and sluggish, conserving energy by ambushing prey instead of chasing it. But the opah’s constant flapping of its fins heats its body, speeding its metabolism, movement and reaction times, according to Dr Wegner and his colleagues at NOAA Fisheries’ Southwest Fisheries Science Center.

“That warm-blooded advantage turns the opah into a high-performance predator that swims faster, reacts more quickly and sees more sharply” explained Dr Wegner, who is the lead author on the study published in the journal Science.

“Before this discovery I was under the impression this was a slow-moving fish, like most other fish in cold environments. But because it can warm its body, it turns out to be a very active predator that chases down agile prey like squid and can migrate long distances.”

The scientists collected temperature data from opah caught during surveys off the West Coast, finding that their body temperatures were regularly warmer than the surrounding water.

They also attached temperature monitors to opah as they tracked the fish on dives to several hundred feet and found that their body temperatures remained steady even as the water temperature dropped sharply.

The fish had an average muscle temperature about 5 degrees Celsius above the surrounding water while swimming about 150 – 1,000 feet (45 – 305 meters) below the surface.

While mammals and birds typically maintain much warmer body temperatures, the opah is the first fish found to keep its whole body warmer than the environment.

“Discoveries like this help us understand the role species play in the marine ecosystem, and why we find them where we do. It really demonstrates how much we learn from basic research out on the water, thanks to curious scientists asking good questions about why this fish appeared to be different,” said Dr Francisco Werner of the Southwest Fisheries Science Center, who was not involved in the study.


Endothermy definition is - physiological generation and regulation of body temperature by metabolic means : the property or state of being warm-blooded . It may be maintained continually or for limited periods only, such as during activity

adj. 1. Chemistry Characterized by or causing the absorption of heat endoergic. 2 parental care, behavioral flexibility, and endothermy (the physiological maintenance of a relatively constant body temperature independent of that of the environment, allowing a high level of activity). Within the class, ecological diversity has resulted from adaptive specialization in food acquisition, habitat preferences, and locomotion

An endotherm (from Greek ἔνδον endon within and θέρμη thermē heat) is an organism that maintains its body at a metabolically favorable temperature, largely by the use of heat released by its internal bodily functions instead of relying almost purely on ambient heat The endotherms primarily include the birds and mammals however, some fish are also endothermic. If heat loss exceeds heat generation, metabolism increases to make up the loss or the animal shivers to raise its body temperature. If heat generation exceeds the heat loss, mechanisms such as panting or perspiring increase heat loss Endothermy is a phenomenon among certain living species that allows one to regulate its body temperature. Ectothermy depends on external sources of heat to regulate the body temperature. Endotherms can acclimatize. Ectotherms cannot. Humans or Homo sapiens are endotherms. As with most biological realities, there are some endothermy pros and cons

Endotherm definition is - a warm-blooded animal. Time Traveler for endotherm. The first known use of endotherm was in 1940. See more words from the same yea An endotherm is any organism (primarily birds and mammals) that maintains a stable internal temperature by means of the heat released through internal functions, namely metabolic reactions in the organs EndoTherm is a unique, energy & fuel saving hydronic heating additive independently proven to save up to 15% on energy consumption Learn endothermy with free interactive flashcards. Choose from 98 different sets of endothermy flashcards on Quizlet

Endothermy Definition of Endothermy by Merriam-Webste

Endothermy in Dinosaurs Dr. Bakker and others have presented numerous lines of evidence for dinosaurian endothermy — some reasonable, some not so reasonable. We shall list some of these and objectively mention some problems with each Endotherms use internally generated heat to maintain body temperature. Their body temperature tends to stay steady regardless of environment. Ectotherms depend mainly on external heat sources, and their body temperature changes with the temperature of the environment Regardless of location (and hence external temperature), endothermy maintains a constant core temperature for optimum enzyme activity. Endotherms control body temperature by internal homeostatic mechanisms Evolution of Endothermy Because endothermy is energetically expensive and evolved more than 100 million years ago (at least in birds and mammals), the selective forces leading to the evolution of endothermy are unclear Endotherms (warm-blooded) are animals that are capable of internal generation of heat. This means endotherms generate their own heat to maintain body temperature at an optimal value. Heat is generated in the internal organs. Two third of the heat is generated in the thorax and 15% of the heat is generated by the brain

Endothermy definition of endothermy by Medical dictionar

  • imise energetic costs by using ectothermy facultatively when entering short- or long-term torpor. They also have a substantial layer of internal dorsal insulation
  • Endothermy definition: a system of temperature control whereby an animal generates heat internally | Meaning, pronunciation, translations and example
  • Endothermy Mammals generate heat internally and have many strategies to keep their internal temperature constant
  • Endothermy means generating heat internally. All mammals are endothermic and most are homeothermic. Some mammals cannot always maintain a constant temperature within. Echidnas have a body temperature that varies between 25-37 degrees C (they are also poor at cooling)
  • Endothermy. Virtually all mammals are endothermic. Endothermy is the ability of an organism to generate and conserve heat in order to maintain a stable, warm body temperature. This ability is commonly referred to as warm-bloodedness. Another term that is used to refer to endothermic animals is homeothermy. Although homeothermy and endothermy.
  • Endothermy, however, is energetically very expensive and requires a great deal of food, compared with the intake of similarly sized ectotherms, to support high metabolic rates. In their 1979 paper, Bennett and Ruben discussed how high levels of activity and aerobic metabolism could have contributed to the evolution of endothermy

Endothermy - definition of endothermy by The Free Dictionar

  1. The evolution of endothermy is a fairly intensively studied niche topic. Evolutionary biologists agree that full or partial endothermy must have arisen separately in a number of species, among which are some sharks, tunas, reptiles, and, either together or separately, birds and mammals. Even some insects are endothermic
  2. The Origin of Endothermy As previously noted, the idea that endothermy has evolved on multiple occasions appears most likely. Mammals, including amniotes, marsupials and the monotremes, are all endothermic, as are the vast majority of extinct species. Similarly, all modern birds are endothermic, and it is widely accepted that theropods and.
  3. Endothermy: The endothermy is the ability of the organism to maintain its body temperature constant. This ability is seen in warm-blooded animals that are capable of surviving in the cold.
  4. The integrated theory of the origin of endothermy presented here is that the several individually definable functions of endothermy, and the structures and processes responsible for it, all evolved in a loosely correlated progression, a small step in this structure here, a small step in that process there, and so on

Endothermy is a typical convergent phenomenon which has evolved independently at least eight times in vertebrates, and is of significant advantage to organisms in extending their niches. However, how vertebrates other than mammals or birds, especially teleosts, achieve endothermy has not previously been fully understood The evolution of endothermy in birds and mammals is an important transition during vertebrate evolution providing an extraordinary instance in evolutionary convergence between groups, pivotal to. ., 1978)

Regional endothermy, the conservation of metabolic heat by vascular countercurrent heat exchangers to elevate the temperature of the slow‐twitch locomotor muscle, eyes and brain, or viscera, has evolved independently among several fish lineages, including lamnid sharks, billfishes, and tunas The evolution of endothermy in birds and mammals is regarded as one of the most important transitions in vertebrate evolution, providing an extraordinary case of evolutionary convergence between..

It is widely agreed that endothermy evolved several times independently. Among recent species, true endothermy, however, is only present in mammals and birds. The evolutionary origin and development of endothermy and metabolism presents a special challenge and has always been a matter of debate (Nespolo et al., 2011) Complex turbinates appear to be an ancient attribute of mammals and may have originated among the therapsid ancestors of mammals, in relation to elevated ventilation rates and the evolution of endothermy Endothermy, the ability to raise body temperature by internal heat production, is unusual in teleost fishes and has only been documented within one suborder, the Scombroidei Endothermy is the ability to maintain body temperatures that are higher than environmental temperatures. Tuna are endothermic and therefore are able to migrate over huge distances and make deep vertical dives in order to catch prey and avoid predators while maintaining a high over-all body temperature

endothermy. there is the heat of increment feeding, called the _____ or thermic effect of food. specific dynamic action _____ is the generation of heat by muscle fiber contraction in an asynchronous manner that does not result in gross movement of the whole muscle is also important heat generating means EndoTherm is a unique energy saving central heating additive, independently proven to save up to 15% on heating bills! But how does it work Although endothermy has been proposed to have been a cardinal character that led to much of this convergent evolution, selection for extensive parental care behaviors is a more compelling explaination. Because extensive parental care encompasses a wide range of behaviors, morphology, and physiology, it may be a key innovation that has. What does endothermy mean? (biology) A form of thermoregulation in which heat is generated by the organism's metabolism. (noun

A) endothermy B) ectothermy C) amniotic egg D) terrestrial habitat All mammals are endotherms: A. True B. False Create an account to start this course toda [184][1] see also p. [123][2] Tissue regenerative potential displays striking divergence across phylogeny and ontogeny, but the underlying mechanisms remain enigmatic. Loss of mammalian cardiac regenerative potential correlates with cardiomyocyte cell-cycle arrest and polyploidization as well as the development of postnatal endothermy The evolution of the endothermy of mammals can be traced to the ectothermy of early reptiles. It is suggested that small endotherms cannot be directly derived from small ectotherms because of the requirement for the simultaneous change in thermal conductance and the rate of metabolism INTRODUCTION. The origin of endothermy remains one of the most debated questions in vertebrate evolutionary physiology (), particularly because modern-day birds and mammals do not share a common endothermic ancestor, suggesting different possible scenarios for its evolution.The proposed proximate and ultimate origins of the rise in metabolic expenditure required to fuel an endothermic rate of.

Endothermy physiology Britannic

'Different lines of evidence indicate that endothermy as it is known from modern birds and mammals may not have been feasible for most, particularly larger, dinosaurs.' 'Two evolutionary events that shaped current vertebrate life were the transition from water to land, and the development of endothermy.' B) Endothermy in birds. Birds are really hot. Birds have body temperatures that range from about 40-44°C (104-111°F). 80% of all bird species are warmer than the warmest 10% of mammal species. Advantages. A primary reason for endothermy is that it allows an animal to maintain high activity levels at all times Endothermy is a feature that appeared late in the evolution of animals, and is found only in modern animals. Warm-blooded animals are also called endothermic or homoeothermic animals, and they generate heat internally and have a thermoregulatory system that maintains a constant body temperature largely independent of their surroundings The evolution of endothermy (that is, of non-shivering thermogenesis) from behavioral thermoregulation of fish can be envisioned as a bypassing of the behavoiral response of fish and a direct stimulation of the Na + pump to produce heat. The attraction of this argument is the ubiquity of Na + transport across membranes

Endotherm - Wikipedi

  1. RM endothermy is an energetically expensive thermal strategy , and its convergent evolution indicates that the extra energetic costs incurred by RM endothermy can be outweighed by some ecological advantages. This topic has been discussed intensively, and two primary,.
  2. Endothermy is the ability of some creatures to control their body temperatures through internal means such as muscle shivering or increasing their metabolism (Greek: ἔνδον endon within θέρμη thermē heat). Some writers [who?] restrict the meaning of endothermy to mechanisms that directly raise the animal's metabolic rate to.
  3. Birds feather flight & endothermy with EVOLUTIONARY PROSPECTIVE and PHYLOGENETIC RELATIONSHIPS is discussed in this article Birds are traditionally classified as class Aves. Birds have adaptations for flight. The major characteristics of this class are: 1. Their appendages are modified to wings. 2. They body is covered by leathers

Endothermy, i.e. the ability for an organism to generate body heat through a specifically dedicated metabolic activity, is considered to have appeared at least twice in the evolution of vertebrates, in the mammalian and avian lineages [1,2] Endothermy continued • Heat production - Resting metabolic rate • The rate that we burn calories at rest through cellular processes (burning ATP to ADP to AMP) - Specific dynamic action • Heat increase after eating from assimilating molecules and synthesizing proteins - Activity (muscle contraction This pioneering work investigates why endothermy evolved in birds and mammals, despite its enormous energetic costs. Vividly narrated and illustrated, this book integrates paleontology, zoology, and physiology to stage a groundbreaking argument that will prove provocative and fascinating for specialists and lay readers alike Terrestrial systems act as a test for the role of endothermy in limiting food chain lengths, as endotherm and ectotherm consumers are often more similar in size in those systems (partially controlling for body size as a variable). Revisiting the energetic efficiency hypothesis: body mass, metabolism, and food chain lengt But endothermy-required obligatory bipedalism could not have arisen in fauna-poor freshwater environments. The possible existence, in faunivorous thecodonts, of functional (or vestigial) cranial salt glands may suggest that the earliest semiaquatic archosaurs originated in fauna-prolific marine environments. If archosaurs were originally.

Endotherm biology Britannic

Broadly, endothermy was much more common in terrestrial systems, and endotherms assumed lower trophic positions (namely, herbivory), both of which were negatively correlated with MFCL. Revisiting the energetic efficiency hypothesis: body mass, metabolism, and food chain length Ruben, Endothermy and activity in vertebrates, Science, vol Endothermy is fundamental to the life of mammals. Mammals must wring as many calories as possible from the foods they eat in order to provide enough energy to heat their bodies. And this is where teeth come in. 'Mammal teeth today' looks at the dental diversity of mammalian teeth in both marsupials and placentals Endothermy (the metabolic production and retention of heat to warm body temperature above ambient) enhances physiological function, and whole-body endothermy generally sets mammals and birds apart from other animals

Endothermy Pros and Cons List NYLN

  1. is that homeothermy is the state or condition of being homeothermic while endothermy is (biology) a form of thermoregulation in which heat is generated by the organism's metabolism
  2. the age of endothermy does not occur at the asymptotic to adult weight, and e is In-'. same stage of growth in all species. Thus, the Adult and asymptotic weight also were considered age of endothermy normally may be flexible in the analysis to test whether the age of endothermy and size are correlated
  3. Some of these animals evolved small body size, and probably endothermy and body fur. Archive 2006-05-01. Dinosaur body temperature: The occurrence of endothermy and ectothermy, Paleobiology, Winter 2003. Endotherm. I remember that I answered the first with a question about the development of body temperature regulation endothermy in mammals
  4. Abstract. Macrophage polarization refers to how macrophages have been activated at a given point in space and time. Polarization is not fixed, as macrophages are sufficiently plastic to integrate multiple signals, such as those from microbes, damaged tissues, and.

Endotherm Definition of Endotherm by Merriam-Webste

  1. Characteristics of endothermy (suggested reading) Thermoneutral zone (TNZ): The range of temperatures at which no extra energy is required to maintain homeothermy. Lower critical temperature (LCT): The lower temperature threshhold at which the animal has to increase its metabolism to maintain body temperature. Upper critical temperature (UCT) The upper temperature threshhold at which the.
  2. um cooling crystallization dust encapsulation materials sludge Show all 9 Subjects Abstract: This study confirmed that the modified industrial sludge can be used as the preparation material of composite powder suppressor
  3. a, and tolerance in various conditions. (Photo :

Endotherm Animals: Definition, Characteristics and Example

The evolutionary success of endothermy in mammals and birds represents an enduring enigma. Relative to an ectotherm of equivalent body size, endotherms expend many times the energy to maintain. Recently, whole-body endothermy has also been described in the opah (Lampris guttatus) . In chondrichthyans, regional endothermy is restricted to lamniform sharks, where it is found in two of the three species of alopids [22-24] and in all species of the family Lamnidae ( and references therein) For example, endothermy is surely one of the most striking animal adaptations, requiring extensive restructuring of many parts (including lung, heart, and skeletal muscle) of vertebrate bodies

Read the entire study at Science: Whole-body endothermy in a mesopelagic fish, the opah, Lampris guttatus . Top photo credit: Ralph Pace/ National Geographic Contact the author at george. Slippery Rock University, Fall 2016PREE - 673 - 89 - Ecosystem EcologyExplainer video project detailing animal adaptations to be either warm or cold blooded We investigated the development of thyroid function during the transition to endothermy in red-winged blackbirds (Agelaius phoeniceus). Thermoregulatory capabilities of blackbirds improve markedly over their relatively short nestling period (10-12 days), with the most striking improvements occurring between days 6 and 8

EndoTherm - Hydronic Heating Additive - Energy Savin

Endothermy may also provide a protection against fungal infection. While tens of thousands of fungal species infect insects, only a few hundred target mammals, and often only those with a compromised immune system. A recent study suggests fungi are fundamentally ill-equipped to thrive at mammalian temperatures. The high temperatures afforded by. Definition of endothermy in the dictionary. Meaning of endothermy. What does endothermy mean? Information and translations of endothermy in the most comprehensive dictionary definitions resource on the web

Endothermy, colloquially referred to as warm-bloodedness, was the physiological ability of some creatures to control their body temperatures through metabolic means, notably by burning food within themselves. To keep a being's body temperature high even in cold weather, that process required that being to use more food. In hot weather, the body of an endothermic being had ways of cooling. Endothermy is significant in vertebrate evolution because it changes the relations between animals and their environment. How endothermy has evolved in archosaurs (birds, crocodiles and dinosaurs) is controversial especially because birds do not possess brown adipose tissue, the specialized endothermic tissue of mammals Endothermy and homeothermy are mammalian characteristics whose evolutionary origins are poorly understood. Given that fungal species rapidly lose their capacity for growth above ambient temperatures, we have proposed that mammalian endothermy enhances fitness by creating exclusionary thermal zones that protect against fungal disease

Recognition of endothermy in dinosaurs can explain both the success and the extinction of this group in the Mesozoic In contrast to ectotherms, endotherms regulate their own body temperature through internal metabolic processes and usually maintain a narrow range of internal temperatures. Heat is usually generated from the animal's normal metabolism, but under conditions of excessive cold or low activity, an endotherm generate additional heat by shivering whole body endothermy circulation Definition routs blood into two cutaneous artries that run along side of body. a cutaneous vein (along artery) brings blood back to the hear The diapsid lineage (birds) and synapsid lineage (mammals), share a suite of functionally similar characteristics (e.g. endothermy) that are considered to be a result of their convergent evolution, but the candidate selections leading to this convergent evolution are still under debate Endothermy is just another word for the term warm-blooded and ectothermy is closest to the meaning of cold-blooded. The obvious pros of endothermy is the ability to perform more activities within a larger range of temperatures. For example, a human would be able to walk around in 100 degree weather Fahrenheit

Endothermy Flashcards and Study Sets Quizle

Endothermy is characterized by high endogenous heat production via combustion of metabolic fuels. This differs from ectothermy in most living organisms, which generally do not produce substantial amounts of internal heat for thermoregulation (Tattersall et al., 2012 Withers et al., 2016). Endogenous heat production is energetically very costly Endothermy. Endotherms vs ectotherms. Characteristics of ectothermic tetrapods. Two aspects to temperature regulation Temperature stability Temperature at which body is regulated. Characteristics of endotherms Advantages and disadvantages of endothermy Hibernation and torpor. The evolution of endotherms. Anatomy and physiology of endotherm Warm bodied fish, including species of shark and tuna, can swim more than twice as fast as other colder bodied species, according to new research. The ability of these fish to maintain a body temperature warmer than the surrounding water (endothermy) allows them to swim at cruising speeds approximately 2.7 times faster than other similar sized cold-bodied species Regional endothermy, the conservation of metabolic heat by vascular countercurrent heat exchangers to elevate the temperature of the slow-twitch locomotor muscle, eyes and brain, or viscera, has.

To suppose that the endothermy of an organism is due to the heat formation at the expense continually (and low efficiency) flow of energetic processes is a little grounded point of view. Against this point of view comes the fact of the existence of cold-blooded animals, in the organism of which the energetic processes are also continually. Lovegrove defines endothermy as the capacity to produce heat on demand from within ananimal (p. 6), and argues that basal metabolic rate (i.e. minimum existence metabolic rate) is primarily generated from metabolic activity in central organs (e.g., heart, kidney, liver, intestines) rather than muscles endothermy. Abstract Body mass positively influences diving capacities in air-breathing vertebrates and has been identified as a key determinant for the evolution of diving. Our review on the relationship between body mass and dive duration (a major parameter of dive performances) encompassed for the first time a wid

Evidence for Endothermy

Recent palaeontological data and novel physiological hypotheses now allow a timescaled reconstruction of the evolution of endothermy in birds and mammals. A three‐phase iterative model describing how endothermy evolved from Permian ectothermic ancestors is presented So-called warm-blooded animals control the temperature of their body at quite a high level. This ability is called endothermy. All mammals and birds are endotherms (homeotherms or homoiotherms). The basic source of the heat is chemical energy from the body's metabolism One of the great unresolved controversies in paleobiology is whether extinct dinosaurs were endothermic, ectothermic, or some combination thereof, and when endothermy first evolved in the lineage leading to birds

Personally, I suspect that external insulation, in the form of fur or feathers, is far more diagnostic of high resting metabolic rates, since it is (a) absent from all living ectotherms, and (b) is functionally linked to tachymetabolic endothermy *Response times vary by subject and question complexity. Median response time is 34 minutes and may be longer for new subjects. Polonium is a rare element with 33 radioisotopes. The most common one, 210Po, has 82 protons and 128 neutrons. Biology: The Unity and Diversity of Life (MindTap Course. adjective Chemistry. noting or pertaining to a chemical change that is accompanied by an absorption of heat (opposed to exothermic) Support the Seattle Aquarium. Your gift will support the Seattle Aquarium's Resilience Fund. Our programming continues with your help. Make a Donatio Ectotherm vs Endotherm . Thermoregulation is the process that enables life to exist in an amazingly wide range of the thermal environment and enhances their ecological and geographical distribution on earth Endothermy and Ectothermy Ch. 6.7, Bush Outline vEffects of temperature on life vThermoregulation vEcological aspects of thermoregulation Outline vEffects of temperature on life vThermoregulation vEcological aspects of thermoregulation Effects of extreme temperatures vCold -- the effects of freezing - physical damage to structures caused by the formation o

Watch the video: What Is An Endotherm And Ectotherms? (December 2022).