On Mon, 30 Apr 2007 10:43:23 CST, kthirtya wrote:

Galen, did you ever come across 'cave insects',
adapted to living in the dark? Or other cave
critters like that - such as fish in underground pools (in
an attempt to keep this in the watery topic
area).

k :-)

Many of them have lost not only eyesight, but also pigmentation. Some
of them have become blind, albino cousins of their same kind that live
on the surface. Others are largely unchanged from those who dwell
outside a cave. There are blind, albino fish, crayfish, spiders,
centipedes, just oodles of things running around in caves. I don't
want to make it sound like a garden environment, it isn't. There
isn't much in the way of nutrients in a cave per se, those that are
there have to be washed in by water or carried into the cave. There
are beetles that live their whole lives in caves, but survive on the
droppings of bats, which must exit the cave to find their nutrition.
It has been discovered, somewhat recently, that there are several
kinds of bacteria that seem to be capable of transforming elements (in
this case, sulphur) directly into energy, without requiring any
external light input. (Well, I think it is pretty remarkable,
anyway.) These bacteria may have played a greater role in cave
development than water, in some cases. There are also some examples
of food chains based on these same bacteria, but I digress. At first
glance, a cave looks like a sterile environment. There is no light
whatsoever, there is nothing growing, just water and rocks and mud.
Surely nothing could survive there. But then there are
speleobiologists and several many universities giving advanced degrees
in speleobiology (speleo meaning "cave" in Greek) so there must be
something to study.
--
Galen Hekhuis
"Mistakes were made"