My $0.02 on subjects raised here:
Oxygen doesn't play well with other elements. Rapid reaction with oxygen tends to give off lots of heat and is called combustion. Slow oxidation is the basis for rust and the eventual degredation of many other materials. The fact that it reacts so readily and can trigger the release of energy while doing so is what makes it a viable basis for a biological metabolism. If you are going to put together a fictional non-oxygen ecosystem, then something else with those properties (like clorine) is needed to fill in for the oxygen. I don't know if you also need something to replace water (which is H20 after all) if you are doing this. I think Earth had oceans before it had an oxygen atmosphere, so I would guess not.
Sillicon-based lifeforms are popular in sci-fi, not only because of the chemical similarities between Sillicon and Carbon, but because having a rock-like creature is neat. However, carbon's role in biology is largely due to the long-chain molecules it forms, which sillicon is less prone to doing. Make of that what you will.
On the subject of genetic drift, the American Continents were isolated from the rest of the world for about 12,000 years and the locals were able to breed with Europeans when they showed up. According to this Wikipedia article, the founding population of these people was fairly small as well. Of course, any genetic tinkering going on increases the rate of change considerably.
The part that wories me about this is the rough technological parity between the races, which someone else brought up. If the Precursors did their thing 80,000 to 50,000 years ago, then a 1% variation in rate of technological advancement would be an 800 to 500 year edge for someone. 500 years ago we didn't even have steam engines and guns were just starting to edge out muscle-powered weaponry. Going the other way, Startrek the Next Generation is only set 360 years from now.
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No, I don't believe the world has gone mad. In order for it to go mad it would need to have been sane at some point.
Oxygen doesn't play well with other elements. Rapid reaction with oxygen tends to give off lots of heat and is called combustion. Slow oxidation is the basis for rust and the eventual degredation of many other materials. The fact that it reacts so readily and can trigger the release of energy while doing so is what makes it a viable basis for a biological metabolism. If you are going to put together a fictional non-oxygen ecosystem, then something else with those properties (like clorine) is needed to fill in for the oxygen. I don't know if you also need something to replace water (which is H20 after all) if you are doing this. I think Earth had oceans before it had an oxygen atmosphere, so I would guess not.
Sillicon-based lifeforms are popular in sci-fi, not only because of the chemical similarities between Sillicon and Carbon, but because having a rock-like creature is neat. However, carbon's role in biology is largely due to the long-chain molecules it forms, which sillicon is less prone to doing. Make of that what you will.
On the subject of genetic drift, the American Continents were isolated from the rest of the world for about 12,000 years and the locals were able to breed with Europeans when they showed up. According to this Wikipedia article, the founding population of these people was fairly small as well. Of course, any genetic tinkering going on increases the rate of change considerably.
The part that wories me about this is the rough technological parity between the races, which someone else brought up. If the Precursors did their thing 80,000 to 50,000 years ago, then a 1% variation in rate of technological advancement would be an 800 to 500 year edge for someone. 500 years ago we didn't even have steam engines and guns were just starting to edge out muscle-powered weaponry. Going the other way, Startrek the Next Generation is only set 360 years from now.
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No, I don't believe the world has gone mad. In order for it to go mad it would need to have been sane at some point.