So, life (on Earth) is much older than what was thought...

[Desdichado]

Perhaps sentience then is an evolutionary reaction against mass extinctions; evolution couldn’t find a solution to keep life alive here. How can life be defended against massive asteroid collisions? So the solution was to sever us from nature and let us come up with our own answer to that problem.

The problem with that, that even many specialists often seem to forget, is that the theory of evolution specifically excludes any "plan" for evolution. It's random. There's no higher consciousness looking at the "end goal"--each and every step on the way must have benefit to the organisms that develop it, or it doesn't last.

 

[Aesmael]

The documentary told that the crash of the two planets boiled down everything on Earth's surface at 4000 degree celsius, and remained so for an extremely long time (thousands of years). Only a few micro-organisms escaped disintegration because they were in some water deep inside the crust, where the cataclysm was less disastrous. So, if what the documentary tells is true, it appears that everything on Earth's surface was vaporized.

At least, all of this is great for developping some Cthulhu adventures!

Except, to repeat, moon rocks have been dated to 3.5 billion years old (or was it more?). But IIRC 500 million years ago was about the time life developed into more complex (interesting?) forms. Cambrian explosion and all that.

That certainly doesn't prevent anything Lovecraftian from happening though. I suppose an adventure might start with the discovery of a strange fossil in a sedimentary layer that should not have any.

And for those who find the impact theory of lunar origin new, consider that the planet in this scenario was the size of Mars before Earth ate it and spat out the pieces. (Whee! Riding on reflected cosmic awesome is fun!)

 

[Nifft]

You'd have me believe that this impact then destroyed the fossils of all the first round of multicellular critters, but left the fossils of the single-celled critters right next to them intact for us to find? That makes no sense.

Devil's advocate: statistically, the most commonly fossilized critter with the widest habitat range is most likely to have its little fossils survive.

So, if we have N multi-cell critters, and M >> N single-celled critters, and the single-cell critters can live deep under the soil and other places where the multi-cell critters cannot... we're likely to have fossils only of the single-cell critters.

-- N

 

[Nifft]

The problem with that, that even many specialists often seem to forget, is that the theory of evolution specifically excludes any "plan" for evolution. It's random.

Yes, but don't forget the Weak Anthropomorphic Theorum: you only get existential questions when the conditions are perfect for sentient critters to evolve.

-- N

 

[JamesDJarvis]

The documentary told that the crash of the two planets boiled down everything on Earth's surface at 4000 degree celsius, and remained so for an extremely long time (thousands of years). Only a few micro-organisms escaped disintegration because they were in some water deep inside the crust, where the cataclysm was less disastrous. So, if what the documentary tells is true, it appears that everything on Earth's surface was vaporized.

At least, all of this is great for developping some Cthulhu adventures!

Documentaries aren't alwasy the best places to find scientific truths about life the universe and everything. I alwys thoughtthe impact theory of the moon was supposed to happen while the molten glob that was to becoem the earth was struck by something.
Certainly a great Cthulhuianic basis for RPG fun.

 

[Zappo]

Well, the 3.5 BYA date is based on fossil evidence, not models of hypothetical processes.

See? I didn't, in fact, RC.

The problem with that, that even many specialists often seem to forget, is that the theory of evolution specifically excludes any "plan" for evolution. It's random. There's no higher consciousness looking at the "end goal"--each and every step on the way must have benefit to the organisms that develop it, or it doesn't last.

Right. Sentience appeared by chance. If we survive the next big asteroid impact, Shag was right, in a metaphorical way. In the same sense that "hawks evolved good eyes to better spot their prey" - yeah, it's reversing cause and effect, but the relation is there. If we don't, eh, who cares.

 

[RedWick]

The problem with that, that even many specialists often seem to forget, is that the theory of evolution specifically excludes any "plan" for evolution. It's random. There's no higher consciousness looking at the "end goal"--each and every step on the way must have benefit to the organisms that develop it, or it doesn't last.

Evolution isn't random, but neither is it predictable. Which basically means all bets are off when it comes to talking about it.

 

[tarchon]

The documentary told that the crash of the two planets boiled down everything on Earth's surface at 4000 degree celsius, and remained so for an extremely long time (thousands of years). Only a few micro-organisms escaped disintegration because they were in some water deep inside the crust, where the cataclysm was less disastrous. So, if what the documentary tells is true, it appears that everything on Earth's surface was vaporized.

I wouldn't completely rule out the possibility that the pre-lunar Earth already had a reasonably evolved surface. It would have been a fair bit smaller at the time. A couple hundred million years might be enough for some sort of primitive life to emerge.

 

[Desdichado]

Evolution isn't random, but neither is it predictable. Which basically means all bets are off when it comes to talking about it.

I'm not sure what you're talking about. The prevailing interpretation (in fact, pretty much the only one I'm aware of, unless you discount crackpot ideas like genetic manipulation by Grays or something like that) is that evolution is "fueled" by random mutations, some of which provide a benefit to the mutated, causing the mutation to be passed on to its offspring.

 

[Someone]

I'm not sure what you're talking about. The prevailing interpretation (in fact, pretty much the only one I'm aware of, unless you discount crackpot ideas like genetic manipulation by Grays or something like that) is that evolution is "fueled" by random mutations, some of which provide a benefit to the mutated, causing the mutation to be passed on to its offspring.

You both are actually right: it has a random part (mutation commonly, though I think there are other mechanisms) and a non-random part (selection)