Ok, so let me see if I understand...
" One thought - How will this impact this entire discussion if we find evidence of life on Mars? Will that lead to the speculation that life must be throughout the Universe, or simply that our isolated planetary system contains life and we still don't have evidence that it "should" exist elsewhere? Can we predict the odds go up everywhere? "
Once N=2 in a sample size as small as our solar system then it's reasonable to conclude that N will be a very large number when the sample size is very large.
Pesse (And I got a big bottle of Scotch riding on N=2..) Mist
If 10 years from now we find a planet just like ours, same size, right kind of star, right distance, water, O2, H and we have NOT found anything on Mars...it is NOT reasonable to think life is there? Would that not be a sample size of 2 in the sense that things grow given the right conditions? But if we found something on Mars that opens the door to reasonable assumption...is that right?
Let me tell you what I think..
I think people put a much too narrow a focus on what is required for 'life' to develop.
I think you just need a stable niche, energy source, and chemical blocks to build with and eventually you'll get 'life' of some sort or another.
Extremophiles on Earth are only called that relative to us. In other words, WE are extremophiles when looked at from their perspective. "OMG! Look at those Hu-Mans living in a neutral Ph environment!"
Think about it, life developed under chemistry much different than exists on Earth today yet life has poked into and thrived in virtually every niche we have examined.
So, in my mind we will find life on every planet in the solar system and on all the moons with an atmosphere (and maybe some without).
The life may be just microbial but I bet we find it.
Mars was far less hostile in the past to life (at least life as we know it in N=1).
Earth deserts look lifeless but dig down a bit and you'll find life. I bet in protected niches and those underground caves we will find life teeming.
If we don't than I suspect something else is at work to make life necessary (seeding?)
Pesse (Extinction is a fallacy. Animals today are just around because chuck norris decided to let them live.) Mist