On Wednesday, March 14, 2001 4:59 PM Robert J. Bradbury bradbury@aeiveos.com
wrote:
> > Well, when continental species get introduced to islands, it's sayonara
> > locals 9 times out of 10, and sometimes very quickly. Earth has an
> > enormous biosphere and bacteria at least swap genes with avidity.
> > I doubt Europa can match that, assuming it has any life at all, simply
> > as there's far less usable energy there.
>
> But with the islands case, you have some species adapted to a
> specific niche where there are no competitors and the incoming
> species are those from the larger continents where they have
> had to compete and survive. They generally come in with
> better "genes" and that is why they win.
But that's the point. The assumption here is that any Europan life would
probably not have the competition Terrestrial life has had to face. (This
is speculative, of course. We might find no Europan life or perhaps the
Europan environment is more varied and any ecosystems there much more robust
than we imagine.)
Also, Europan life would most likely be adapted to a limited set of
environments and there mgiht not be much movements.
> The proper comparison given your example is species coming into
> an island just after it has been formed when there is no established
> ecosystem to take advantage of. In that situation the "mainlanders"
> don't have an easy time of it. Only a very limited set of species
> that have evolved to deal with the resource poor conditions manage
> to make a go of it.
This is true, though on Earth, typically, the first species to land on a new
island are often birds just looking for a place to roost or spiders who eat
any insects that drop by.:)
> Given the low energy availability you cite on Europa, the species
> from Earth that would manage to compete effectively are probably
> few and far between.
I don't think so. Earth possesses many different microenvironments, some
more like Europa, such as Lake Vostok in the Antarctic. Europa would seem,
prima facie, not to have such variations. So, my bet would be that while
percentage-wise most Earth life would find Europa inhospitable, in terms of
raw numbers -- numbers of species and of organisms that might be able to
survive there -- Earth has Europa beat.
> The scientific insights that could
> be derived from any species that were discovered growing in
> such an environment would likely be very great.
I see no need to contaminate Europa and think any ET life would add a lot to
our knowledge.
> Nothing like
> a few billion years of evolution under really poor conditions
> to make you tougher than steel...
Well, if that's true, why haven't lichen overgrown Earth?:) (There are many
other examples, but usually organisms that evolve to fit really tough --
which is a relative term anyhow; bacteria that survive in a low or no oxygen
environment often find it tough to survive in what we or E. coli would find
normal -- places are ones that were pushed out of other ones on Earth.:)
Cheers!
Daniel Ust
http://uweb.superlink.net/neptune/
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