February 26, 2004

If you take a look at some of the orbital imagery of Meridiani, you
will see that there appears to be quite a bit of reef and outcroppings
around, but if you look very carefully, you notice that most of these
are the eroded away circular remnants of earlier cratering. Eroded as
in melted, slumped or subsided, as in ice and water.

http://www.msss.com/moc_gallery/e13_...8/E1801275.jpg

Now think about what a putative or hypothetical 'porifera jonathanii'
would have to deal with in surviving. Not only would it have to deal
with extreme environmental fluctuations, melting and thawing of ice
sheets, runoff etc., but it would also have to deal with the
occasional incoming impacts. A better way to propagate itself *and*
deal with random impacts in such an environment, is to leave millions
of hardened, impact resistant, aerodynamically stable gemmules laying
around, ready to ride the (shock) waves into the next quadrant.

If you choose the water and ice hypothesis then you have to start
thinking about life, and fossils. If you choose the fossil hypothesis,
you have to start thinking about natural selection and biology, in
addition to planetary geology.

Here is a modern paper on gemmulation and oogenesis. It describes the
'launch pad' very nicely. I propose that many large, robust, spherical
gemmules could be a result of natural selection.

http://www.bio.pu.ru/win/embryo/art/haplosclerida.pdf

Just a thought.

Thomas Lee Elifritz
http://elifritz.members.atlantic.net