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Re: Words

>From an often overwhelmed casual reader - thanks for this post!

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Sally Pfeiffer
Gallery 2/Space VTL

>>> "philidor11" <philidor11@snet.net> 05/04/01 08:27PM >>>
HP Benoit also requested the definition of some of these words, so if you
don't mind, I'll use his list:
- terramegathermy
- gigantothermy
- bradymetabolism
- bradyaerobic
- poikilothermic
- tachymetabolism
- tachyaerobic
- pelagomegathermy ( I read pelagic, here )
- anaerobiosis

Some of these are from a past posting of mine, which I cribbed from HP
Paul's paper as quoted by HP Marjanovic:

Bradyaerobic: Bradyaerobes have low rates of active oxygen consumption (the
reptilian condition).
Bradymetabolic: Rates of oxygen consumption are low under resting conditions
(the reptilian condition).
Ectothermic: In ectotherms the majority of body heat is acquired from the
environment. These have LoMRs (reptilian condition).
Endothermic: In endotherms the majority of body heat is generated
internally. Most examples have HiMRs (avian-mammalian condition), but LoMR
giants like leatherback turtles can conserve enough body heat to be
endothermic (McNab, 1983; Spotila et al., 1991).
Hyperanaerobic: The very high levels of anaerobic power generated by the
muscles of many reptiles.
Tachyaerobic: Tachyaerobes have high rates of active oxygen consumption (the
avian-mammalian condition) [and either have a tracheal system like insects
or leaky cell membranes].
Tachymetabolic: Rates of oxygen consumption are high under resting
conditions (the avian-mammalian condition)."

Then the rest:
Anaerobiosis:  The complete absence, or (loosely) the paucity, of gaseous or
dissolved elemental oxygen in a given place or environment. (From Singleton
& Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)

Gigantothermy:  The term gigantothermy has been used to describe the
physiological state predicated on slightly elevated metabolic rate combined
with large body size, the use of peripheral tissues as insulation, and
active control of blood flow to retain or to disperse heat from the body as
appropriate. Most dinosaurs were excellent candidates for gigantothermy.

Heat production is related to body mass, while heat loss is related to body
area. As an animal gets larger, its body area decreases relative to its body
mass, so heat loss decreases and it becomes more efficient at maintaining
body temperature. This theory, termed 'gigantothermy', together with the
possible aid of plates, spikes, frills or nasal cavities used as heat
exchangers , proposes that large dinosaurs living for the most part in a
warm environment could in fact have found the body temperature of a fully
warm-blooded animal thermally stressful and disadvantageous.
There are a number of counter-arguments...

Poikilothermy:  A condition in which an organism's body temperature relies
on and varies with the temperature of the environment.

Well, pelagic has to do with the open seas, so I'll make a guess this has to
do with large marine animals, in contrast to terramegathermy.  Given the
supportiveness of water, I suspect that the metabolism needed would not have
to be as high.(See below)

Terramegathermy (from an 11/14/95 posting by HP Paul):  I have also been
working on the hypothesis of terramegathermy, which argues that land giants
over one tonne must have high metabolic rates in order to power the large,
powerful hearts needed to oxygenate the large limb muscles needed to carry
great mass in 1 Gravity, and to pump blood up tall necks. Because many
dinosaurs were over 1 tonne, high energy budgets are suggested

I hope this helps!