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Heterothermic Metabolism
Name: Grant
Status: Other
Grade: Other
Location: IN
Country: United States
Date: February 2008
Question:
I assume that cold blooded animals metabolize glucose in
essentially the same way as warm blooded one. why then are unable to use
the heat from the metabolic process to heat their bodies as warm blooded
creatures do?
Replies:
This is just an alternative life style. Some animals "spend" some of the
energy they get from glucose to keep their thermostat set at the same
temperature all the time. This allows them much quickness and freedom of
movement because they are always warm. The downside is that they have to
eat more to compensate. Other animals don't spend any of their energy budget
on keeping warm and therefore don't need to eat as often. The problem is
that they tire easily and after a burst of movement need to recover, and
they don't move quickly in the morning when it's cooler. This also means
that in colder climates they usually need to hibernate or go dormant because
their body temperature goes down with the environmental temperature.
vanhoeck
Animals used to be categorized as ‘warm-blooded’ or ‘cold-blooded’, but that’s
a bit of an oversimplification. The preferred terms now include ‘endotherm’ for
certain ‘warm-blooded’ animals and ‘ectotherm’ for some animals that used to be
called ‘cold-blooded’ (but be careful! there are many examples that don’t fit
into either!).
All animals must regulate their temperature to some degree to live, but they
don’t all have the same target temperature or the same ways of doing it. Some
have many tools in their temperature-toolbox, and some have very few. It’s not
accurate to think that “Cold-blooded” animals are “unable to use the heat”
generated in metabolism -- they just have a different target temperature,
and/or have a different set of methods they use to control their body
temperature.
In all organisms, metabolism generates heat. Metabolism is just one tool
of many that animals have to regulate their body temperatures. Some organisms
can become more active (e.g. generate more heat through metabolism) to warm up
their bodies, and then become less active and cool down their bodies. Other
animals control how they exchange heat with their surroundings (moving to the
shade or into the sun, moving to a warmer or cooler area in water, etc.).
Physiological changes are also used in animals (sweating, panting, flowing
more or less blood to extremities, etc.) to raise or lower temperature. Other
organisms have very little control – not only are they strongly influenced by
their surroundings, but they also don’t have very good ability to change their
temperature.
Specific animals have different targets and different techniques, so to get more
specific, you would need to pick an example to discuss.
Hope this helps,
Burr
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