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Biology/Body Temperatures


Good day.  I have two main questions.

First:  how did evolution give us a resting body temperature of precisely 98.6 degrees?  And why?  Are there inherent benefits to that temperature, as opposed to 95 or 103 degrees?  Could you explain the evolutionary reason and mechanism of our body temperature?

I see that animals have different body temperatures.  Why do different mammals have different body temperatures?  Whats that bout?  Animals seem to have higher temperatures than us.  Could you explain why that is, and the evolutionary implications of the varying body temperatures of mammals?

Second, why, if our body temperature is 98.6 degrees, does air or water that is 90 degrees feel hot and why don`t we feel cold when it`s 70 degrees outside?  Why does  staying in water thats 98 degrees for an extended period of time (if we keep drinking water) cause hyperthermia?  

Any additional observations or interesting info on the subject would be welcome too.


Cole LaValley

hope this helps;The normal core body temperature of a healthy, resting adult human being is stated to be at 98.6 degrees fahrenheit or 37.0 degrees celsius. Though the body temperature measured on an individual can vary, a healthy human body can maintain a fairly consistent body temperature that is around the mark of 37.0 degrees celsius.

The normal range of human body temperature varies due to an individuals metabolism rate, the higher (faster) it is the higher the normal body temperature or the slower the metabolic rate the lower the normal body temperature. Other factors that might affect the body temperature of an individual may be the time of day or the part of the body in which the temperature is measured at. The body temperature is lower in the morning, due to the rest the body received, and higher at night after a day of muscular activity and after food intake.

Body temperature also varies at different parts of the body. Oral temperatures, which are the most convenient type of temperature measurement, is at 37.0 C. This is the accepted standard temperature for the normal core body temperature. Axillary temperatures are an external measurement taken in the armpit or between two folds of skin on the body. This is the longest and most inaccurate way of measuring body temperature, the normal temperature falls at 97.6 F or 36.4 C. Rectal temperatures are an internal measurement taken in the rectum, which fall at 99.6 F or 37.6 C. It is the least time consuming and most accurate type of body temperature measurement, being an internal measurement. But it is definitely, by far, not the most comfortable method to measure the body temperature of an individual.
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The heat in your body comes from the burning of different forms of carbon, mostly glucose. The body breaks the glucose down in many steps to harness as much energy as possible, but there is excess energy and that goes to heating your body. When we consume and digest food, the chemical reactions that occur are very similar if not identical to combustion. As everyone knows in the case of combustion, an abundance of heat is released as a by-product and warm blooded organisms use this heat constructively to maintain a consistent internal temperature. You'll notice that when we are cold, we often will shiver or run in place. We do this to heighten our metabolic rate and combust fat reserves to generate additional heat to maintain our core temperature. We will die if our core temperature goes too low because we will be unable to produce enough energy fast enough to power our vital organs or neurons.

The evolutionary reason we have a consistent core temperature involves metabolism as well. In chemistry, the rate at which a chemical reaction is completed depends on the temperature of the reactants. The higher the temperature, the higher the rate of reaction. Animals that are warm blooded can consistenly generate plenty of energy whenever they'd like, and animals that need more or less energy on a regular basis have higher or lower core temperatures.

You may have noticed that cold blooded animals are slow or lethargic during times of day that are cold or if they have not "sunned themselves" to warm up. This is because the metabolic reactions that are generating the power to get them moving are progressing at a slower rate. see also     Science   Biology   Human Biology  


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