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Topic: Homeotherms

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 NationMaster - Encyclopedia: Poikilothermic
Many homeothermic, or warm-blooded, animals also make use of these techniques at times.
For example, all animals are at risk of overheating on hot days in the desert sun, and most homeothermic animals can shiver.
However, in a given niche, homeotherms often drive poikilothermic competitors to extinction because homeotherms can gather food for a greater fraction of each day.
www.nationmaster.com /encyclopedia/Poikilothermic   (617 words)

 Arguments Against Warm Bloodedness in Dinosaurs. Who Lies Sleeping? The Dinosaur Heritage. AskWhy! Publications.
Mass homeotherms must necessarily have been displaced by creatures that were actively warm-blooded irrespective of size.
The cartoon depicts a large sauropod, the mass homeotherm, comatose and unresponsive in the freezing rain, failing to notice tiny rat-like mammals, active despite the cold, eating him alive from the tip of his tail.
How could cold-blooded dinosaurs or even mass homeotherms survive here in the cold and darkness of winter—they had to be warm-blooded Migration after the fashion of the caribou is just a possibility but again implies a highly active animal.
www.adelphiasophism.com /awwls/00/wls116.html   (1885 words)

 Ask a Scientist - High body temperatures
These warm-blooded species are called homeotherms (as opposed to the cold-blooded poikilotherms).
One way homeotherms generate heat is by shivering.
As muscles convert energy stores into motion, much of the energy is converted to heat.
www.hhmi.org /cgi-bin/askascientist/highlight.pl?kw=&file=answers/general/ans_042.html   (468 words)

 Straight Dope Staff Report: What makes some animals cold-blooded and others warm- blooded?
In endotherms, most of the heat is generated internally, through metabolism, while in ectotherms, most of the heat comes from external sources, such as the sun.
For example, some desert lizards, although ectotherms (receiving most of their heat from sunlight) are behavioral homeotherms.
In the morning they bask to bring their body temperature up to activity level; at mid-day they seek out shade to avoid overheating.
www.straightdope.com /mailbag/mwarmblood.html   (656 words)

 Respiration Study Sheet
Homeotherms are able to maintain their bodies (and the component cells thereof) at an optimal temperature for enzyme-catalyzed reaction rates.
But, homeotherms require 10x to 30x as much food and oxygen as poikilotherms.
Respiration is the process that enables organisms to release the chemical energy that is stored in food so that they can use it.
www.wsbd.net /biology/umn1009/bioss5.html   (159 words)

 Control of metabolic rate is a hidden variable in the allometric scaling of homeotherms -- Chaui-Berlinck et al. 208 ...
B (the metabolic rate of a homeotherm) converges to SMR.
There are internal and external conditions that once met supposedly lead the metabolic rate B of a homeotherm to the SMR.
and B in conditions representing a large homeotherm (A), a homeotherm weighing a little less than 50 g (B) and a 10 g homeotherm (C).
jeb.biologists.org /cgi/content/full/208/9/1709   (4038 words)

 Lecture notes of Chapter 1
Describe the internal reflexive thermoregulatory responses of homeotherms 2.
Homeotherms = warm blooded = gentlemen Mammals and birds are homeotherms, they remain an almost constant body temperature, range of 36 - 37.2 C degree.
Note: 1 kilocalories = enough heat to raise the temperature of 1000 grams of water 1 degree C. Internal reflexive thermoregulatory response of homeotherms See Transparency (1).
www.humboldt.edu /~sh4/p321notech10.htm   (1970 words)

 The Metabolic Cost of Swimming in Marine Homeotherms (ResearchIndex)
This document uses CoBlitz to cache paper downloads.
If your firewall is blocking outgoing connections to port 3125, you can use these links to download local copies.
Abstract: This paper describes a model of the metabolic cost of swimming in pinnipeds and its application to other marine homeotherms.
citeseer.ist.psu.edu /hind97metabolic.html   (541 words)

  Critical size of newborn homeotherms.
Balmer RT; Strobusch AD It is shown that for cylindrical and spherical bodies there is a critical radius below which the addition of any form of insulation to the body will increase rather than decrease the cooling of the body.
A critical weight is derived from the critical radius for basically spherical animals which compares favorably with typical birth weights of various altricial homeotherms.
The effect of the overall conductive-convective heat transfer caused by a basically cylindrical animal rolling up into a ball is also discussed.
www.medscape.com /medline/abstract/863818   (145 words)

Homeothermic mammals regulate their body temperatures, and hence their energy expenditure, to a relatively constant and fairly high rate (Fox, 1984).
Therefore, the purpose of this laboratory exercise was to test the null hypothesis that metabolic rates of poikilothermic animals are greater than or equal to those of homeothermic animals, and that metabolic rates of large homeotherms are greater than or equal to those of small homeotherms.
When this principle is applied to homeothermic animals, it is apparent that as the size of the animal decreases, its surface area to volume ratio will also increase and must be accompanied by a corresponding increase in metabolic activity in order that body temperature be maintained in spite of the greater radiational cooling.
csm.jmu.edu /biology/garrisne/Physiology/SampleReport.htm   (1010 words)

Some larger poikilotherms, by virtue of their substantial volume to surface area ratio, are able to maintain relatively high body temperatures and high metabolic rates.
This phenomenon, known as gigantothermy (inertial homeothermy), has been observed in sea turtles and great white sharks, and was most likely present in many dinosaurs and ancient sea reptiles (such as ichthyosaurs and plesiosaurs).
However, large dinosaurs are not poikilotherms, but homeotherms (homeothermic all the time) because of their large bodies.
www.oobdoo.com /wikipedia/index.php?title=Cold-blooded   (918 words)

 Human Thermoregulation and Hair Loss
Homeotherms are organisms that maintain their body temperature within a very narrow range through a variety of thermoregulatory structural and physiological devices in widely varying environmental temperatures.
Homo sapiens is a homeothermic species that must maintain a relatively stable body temperature no matter what environmental conditions individuals are exposed to.
The function of the thermoregulatory system of a homeothermic organism is to maintain a constant core body temperature under different environmental conditions.
www.modernhumanorigins.net /anth501.html   (9745 words)

 Wildlife Habitats and Management Home Page
  While homeotherms can remain completely active over a wide range of ambient temperature, the cost this adaptation is relatively high, because the greater expenditure of energy involved requires a correspondingly greater food intake than for poikilotherms whose body temperature is maintained primarily by the external environment.
Homeotherm’s adaptations to exist under varying ambient temperatures are almost always supplemented by dependence on surrounding conditions and/or structures that either reduce loss of heat or reduce over-heating.
Homeotherms not only can produce needed heat to keep the body warmer than their surroundings, but also can dissipate heat to keep themselves below otherwise damaging ambient levels.
fwcb.cfans.umn.edu /courses/FW5603/Lecture_6_Sept_21.htm   (3914 words)

 [No title]
Homeotherms - are at the other end of the spectrum, these animals have a variety of structural and physiological adaptations which maintain their body temperature at a very stable value in spite of wide fluctuations in their environmental temperature.
Humans are homeotherms, except under some pathological conditions.
This compensates for the increased thermal output of the active muscles and maintains core temperature within the homeothermic limits.
www.science-aquinas.co.uk /biology/body_temp.htm   (1743 words)

 Thermoregulation in Therapsids
Most reptiles are heterothermic ectotherms; however, some large crocodiles -- despite being ectothermic -- are actually able to live as homeotherms by a combination of heat retention (due to their body size) and behaviorally-based thermoregulation strategies (e.g.
Homeothermic endothermy provides important benefits: it can increase activity levels significantly, free the animal from behavioral obligations that would otherwise be imposed by ectothermy, and allow it to survive in a wider range of environmental conditions.
For this reason, these early therapsids may have been ectothermic "inertial homeotherms" that used their body mass to maintain a relatively low, stable temperature.
www.geo.brown.edu /geocourses/QE/fr/classtopics/Evolutio/CarlTakei/CarlTakei.HTM   (1571 words)

 Arguments Against Warm Bloodedness in Dinosaurs. Who Lies Sleeping? The Dinosaur Heritage. AskWhy! Publications.
The huge, noble sauropods might have been stately homeotherms, needing less internally generated heat, because their bulk retained it.
Closer to the poles or up mountains a temperature must be reached where the mass homeotherms would lose body heat becoming less active whereas a fully warm blooded animal with its built in thermostat would remain active.
Furthermore, if dinosaurs were anything other than warm-blooded they could never have displaced the mammals, or rather the mammal-like reptiles, 200 million years ago and could only have survived by taking the role of our mainly small, present day reptiles.
web.ukonline.co.uk /michael.magee/awwls/00/wls116.html   (1885 words)

 Wildlife Habitats and Management Home Page
Since our focus is on quadrupeds, we are concerned with both homeotherms and poikilotherms.
An underlying issue in the environmental relations of both homeotherms and poikilotherms is how well they can adjust to threats from extreme ambient temperatures through use of external objects.
Energy required is much higher; hence food is correspondingly greater than in poikilotherms whose body temperature is maintained primarily by inputs from the ambient temperature.
fwcb.cfans.umn.edu /courses/fw5603/lect9_thermal.htm   (2502 words)

 Margaret Judge   (Site not responding. Last check: )
Homeotherms maintain a constant internal body temperature, even when they are subjected to fluctuating environmental temperatures.
Therefore, it was expected that their respiration rates would increase when exposed to cold temperatures.
To record respirations rates, a gas sensor probe was used to measure the amount of Carbon Dioxide (CO), which is an output of respiration, in a gas chamber.
spot.colorado.edu /~basey/judge.html   (470 words)

 AllRefer.com - body temperature : Warm-blooded Animals (Homeotherms) (Anatomy And Physiology) - Encyclopedia
AllRefer.com - body temperature : Warm-blooded Animals (Homeotherms) (Anatomy And Physiology) - Encyclopedia
In many mammals and birds the body temperature shows more pronounced cyclic variations than in humans.
For example, in hibernators the body temperature may lower to only a few degrees above the environmental temperature during the dormant periods; mammalian hibernators reawake spontaneously and in their active period are homeothermic.
reference.allrefer.com /encyclopedia/B/bodytemp-warm-blooded-animals-(homeotherms).html   (595 words)

Furthermore, the thermogenesis of young precocial homeotherms does not bear as close a relationship to body weight as that of the adults.
The presence of adaptive differences in basal metabolic rates is thus by no means so absolutely precluded as has been alleged for adult homeotherms on the basis of the general quantitative relation of their basal metabolic rate to body weight.
(1950b) presented a simplified model of the heat economy of a homeothermic organism and discussed the quantitative relationships involved and the significance of insulation and thermogenesis, in particular, in thermoregulation.
elibrary.unm.edu /sora/Auk/v081n03/p0281-p0307.html   (18089 words)

Insects that warm their flight muscles by vibrating them in place.
Many homeothermic, or warm-blooded, animals make use of these techniques at times.
However, in a given niche, homeotherms often drive poikilothermic competitors to exinction because homeotherms can gather food at more times than poikilotherms.
www.ebroadcast.com.au /lookup/encyclopedia/po/Poikilothermic.html   (372 words)

 body temperature. The Columbia Encyclopedia, Sixth Edition. 2001-05
Mammals and birds are termed warm-blooded, or homeothermic, i.e., they are able to maintain a relatively constant inner body temperature, whereas other animals are cold-blooded, or poikilothermic, i.e., their body temperature varies according to the temperature of the environment.
The body temperature of fishes must remain close to that of the surrounding water, because heat is lost directly into the water during respiration; however, in some fishes, such as the bluefin tuna, a special network of fine veins and arteries called the rete mirabile provides a thermal barrier against loss of metabolic heat.
The mechanism of temperature regulation in homeotherms is considered an important evolutionary advance in that physical activity in such animals can be relatively independent of the environment.
www.bartelby.com /65/bo/bodytemp.html   (667 words)

 Maintaining Dynamic Equilibrium   (Site not responding. Last check: )
Homeotherms are animals that maintain a constant body temperature.
Poikilotherms are cold blooded animals whose body temperature depends upon the environmental temperature.
Heat is a by-product of metabolic processes and there are several ways in which heat loss is controlled through the skin.
www.pwc.k12.nf.ca /wadey/2201/notes/unit3/u3_homeostasist.htm   (314 words)

 Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal
For example, some species of sea turtles are homeothermic some of the time.
They float on the surface of the ocean to absorb heat and then, after submerging again, stay homeothermic for periods of time because of their sheer size.
Their body temperature may also decrease when they float on the surface of the ocean at night, depending on the surrounding temperature.
www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=cold-blooded   (913 words)

 Homeostatic Control Systems   (Site not responding. Last check: )
Species are often categorised as hot-blooded (homeotherms), cold-blooded (poikilotherms), endotherms, ectotherms, regulators, compensators, or conformers.
The others -- cold-blooded animals or poikilotherms -- differ from homeotherms in lacking the central autonomic thermal controls (the hypothalamus in mammals, and the spinal cord in birds), the continuously high body temperatures, and the emphasis on thermoregulation as a balance between metabolic heat and insulation (in the form of feathers or fur).
Both homeotherms and poikilotherms have biological stabilisation in the face of changing external temperature by homeostatic feed-back control mechanisms: in homeotherms it is the temperatures of particular parts of the body which are the controlled variables, whereas in poikilotherms the controlled variable might be, for example, metabolic rate [6, Chap.
www.cogs.susx.ac.uk /users/adrianth/ecal97/node12.html   (1061 words)

 MEDLINE_1996-2006 - Resultado de la búsqueda <página 1>
Colonization of homeotherms by vascular trematodes required precision egg laying near the conduit for egg passage to the external environment and avoidance of pathogenesis that might result in the premature death of the host.
Evolution of dioecy from the hermaphroditic condition may have proceeded through androdioecy in which hermaphrodites were specialized for precision egg placement in the vascular system and larger adults became functional males.
Eggs are sequestered within the portal system of homeotherms, thus restricting egg dispersal and resulting pathogenesis to less sensitive organs.
www.bireme.br /cgi-bin/wxislind.exe/iah/online/?IsisScript=iah/iah.xis&nextAction=lnk&base=MEDLINE_1996-2006&exprSearch=9406775&indexSearch=UI&lang=e   (389 words)

 Temperature Regulation in Homeotherms   (Site not responding. Last check: )
Animals capable of temperature regulation within a given range are deemed homeotherms (alternatively homiotherms or homotherms).
They have the ability to regulate temperature via negative feedback control.
Other corrective mechanisms are involved, such as a drop in metabolic rate and shivering when temperatures drop.
www.marquette.edu /~buxtoni/DW/temperaturereg.htm   (239 words)

The rule of thumb is that they go faster when they are warm and slower when they are cold.
The advantage of being homeothermic is that you can always maintain yourself near one optimum temperature and you will now have all your internal chemical reactions functioning at their best.
This means that you can think, move, digest, etc. with your best possible speed and efficiency.
www.ufaqs.com /wiki/en/wa/Warmblooded.htm   (1176 words)

 Avoiding the Big Chill
All homeotherms face the same dilemma, how to maintain a constant body temperature in a varying environment.
In man these "goose bumps" have no effect, but in other homeotherms the fluffed up fur or feathers increase their insulative values considerably.
Further cooling triggers involuntary muscle contractions, shivering, (remember--increased activity leads to increased metabolism leads to increased heat production) which is extremely effective for a short time.
www.oswego.edu /wscp/avbgchil.html   (6677 words)

 Current Research: Raul Suarez
The anatomical and physiological correlates of these differences have been well studied, but the biochemical basis for them is poorly understood.
I am very interested in how morphology, physiology, and biochemistry together might constrain animal size and maximum rates of metabolism.
When muscles work at their maximum power outputs, metabolic rates increase by up to several hundred-fold.
www.lifesci.ucsb.edu /eemb/faculty/suarez/research/research.html   (511 words)

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