Hey DV,

I never took biology, which is a shame because I just started getting interested. Anyway, for the past few months I've been doing my own research on evolution, and more recently on abiogenesis.

There are two things I like about abiogenesis: 1) It doesn't seem as if it would be that unlikely to happen, and 2) Once it happens, evolution naturally begins to happen.

So recently someone was talking to me about SETI, and it got me thinking about aliens, but with my new knowledge. And I have to say, it kind of worries me really. My argument always used to be, "Well the universe is so vast. If intelligent life could happen here surely it could happen elsewhere", but the more I think about it, the more I doubt it.

Here's a very brief story of evolution for us: Once we had very basic simple cells through abiogenesis, eukaryotic cells arose. These made the first multicellular organisms. These at first were simiar to sea-sponges, and the very first to have any specific shape looked something like jellyfish. From a gene-centered point of view, these are just fine, because they, obviously, survive and get to pass down their genes. One day a genetic mutation came along (cut a long story short), and the neuron was invented. Please note that mutations in the genes are RANDOM. The very first animals to use these efficiently were things that were something like flatworms. The planaria for instance has a very basic body, two basic eyes, and a very basic brain. That's it. No organs or anything. From there it was pretty straight forward. As the evolutionary tree split into many branches, intelligence became a fitness factor, so all the animals had to become more intelligent to survive. Out of all the millions of species that have existed with a brain, humans are the only ones that have ever been able to use this intelligence to look outwards into space for other beings. Now, look back a bit, and take note that none of this would have happened if you didn't get this genetic mutation that made a nerve cell able to transmit electricity.

So, assuming abiogenesis has happened elsewhere in the universe (which I seriously assume it must have), and evolution taken over (even if it doesn't use DNA like ours), then we have to conclude that any animals (if they ever even left the ground!) that got intelligent enough to have brains must have evolved something that can act as a brain - something that can take in information and reformat it, process it, and do something with it. Once this happens, we have to assume that the environment grew complex enough for the brain to grow complex enough. Once that happened, we have to assume the brain is able to break free of only concentrating on survival (like we have - the only species on Earth to have done it so far), and then, become intelligent enough to be able to look for aliens.

Does this not trouble anyone else? I've always had this feeling that there must be intelligent life out there, but now the probability of this happening seems to have dropped in my head, and if it has happened, I don't think it would have happened very often.

Your thoughts?