RE: [Killietalk] Cold water killies

["Kray, Edd" <Edd_Kray at rf.doe.gov>]

Wright Huntley observes:

"There's no one answer to that one, Rusty. Some shallow-puddle killies 
have adapted to take wide, sudden changes in temp., while big-water fish

like *lamprichthys* like it rather constant.

The fishes of the Gabon highlands live in year-around even-temperature 
cool waters, while coastal fishes of either Africa or SA tend to suffer 
more heat and are often less cold tolerant."

One of my favorite "topics of wonderment"! Have you asked why one
species favors or is adapted to a specific temperature range vs another?

It's all a matter of enzyme kinetics and the abilities of the enzymes
within the species to catalyze it full compliment of biochemical
reactions within either very slim or very wide temperature ranges. All
enzymes being proteins are very temperature specific and will word best
(or work period) within specific temp ranges. This is based on the
effect of temp on its unique "folding". Some enzymes can be VERY temp
specific in their functionality, others are more forgiving and work over
wider ranges. It seems that a species adapted to a very temp stable
environment (equatorial) would develop enzymes with a slim range of temp
adaptability. Others, like our temperate climate killies (100 degrees to
freezing here in CO) would, of necessity, have more "flexible" enzymes
that function over a much wider temperature range.






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