Animal temperature (Introduction)

by David Turell , Thursday, May 05, 2016, 23:40 (3122 days ago)

There is no known mechanism that transformed the early animals who were cold-blooded to warm-blooded. Cold blooded means having a body temperature dictated by the surrounding temperature. Warm-blooded animals maintain a standard range of internal temperature: - http://www.evolutionnews.org/2016/04/understanding_t102811.html - "The human cell is able to harness only about one-quarter of the energy released from the breakdown of complex molecules like carbohydrates, fats, and proteins. The remaining three-quarters is released as heat into the body. As with any working machine, the more active the body, the more heat it releases. - *** - "Humans, like birds and most mammals, are able to regulate their core temperature at a level that is usually above their surroundings, and sometimes lower than it as well. They accomplish this through increasing their cellular respiration and releasing more heat from their metabolism, altering blood flow in the skin, sweating, panting, shivering, and releasing heat by breaking down fat. In this way they are able to control their core temperature from within....The increased need for energy to accomplish this type of thermoregulation requires a high resting metabolic rate, so these organisms have a tachymetabolism (tachy = fast + metabol = to change). In general, birds and mammals are endotherms and homeotherms with a tachymetabolism. - "Most insects, reptiles, fish, and amphibians, are not able to maintain a regular core temperature from within, and are therefore more dependent on the temperature of their surroundings. They are therefore called ectotherms (ecto = outside + therm = heat).... In order to live within these temperature guidelines, these creatures do not need to provide themselves with as much heat energy as those that are warm-blooded. These creatures tend to have a lower resting metabolic rate or bradymetabolism (brady = slow). - *** - "Warm-blooded animals are, in general, able to forage for food faster and defend themselves better in a wider temperature range than cold-blooded animals. Additionally, warm-blooded animals can support highly-complex energy-dependent organs like the mammalian brain. - "However, to maintain a core temperature that is often far higher than its environment, warm-blooded animals must use more of the energy they obtain from food as heat. This means that warm-blooded animals require much more food (often about five to ten times more) than cold-blooded animals to survive. - *** - " Whether cold or warm-blooded, all life forms, even bacteria and amoebae, have some sort of thermoregulatory mechanism. - *** - " One of the main differences between warm-blooded and cold-blooded organisms is that the former can generate more heat from their metabolism than the latter. It is important to note that when cold-blooded animals increase their level of activity, they give off more heat just like warm-blooded ones do. The key difference between them is that, in general, whether at complete rest or with activity, warm-blooded animals tend to give off more heat than cold-blooded ones. - *** - "It appears that not only do the cells of cold-blooded organisms have fewer mitochondria and so release less heat through cellular respiration, but the process of cellular respiration seems to be different as well. In the last few decades, scientists have shown that there are uncoupling proteins (UCPs)within the cells of most organisms, which, particularly in warm-blooded ones, seem to reduce the amount of energy their cells store as ATP and cause the release of more heat. - Comment: Huge differences, and we have no idea how it happened, but the higher metabolism of the warm bloods allows for a bigger more complex conscious brain. Pre-planning?