June 12, 2012Ok my post got deleted so here goes... again...
I think it's folly to assume the engineers didn't evolve.... we know almost nothing about them. Also I think the theory that humans "evolve" is flawed. While yes we do advance in our thinking and technology (which the Engineers have already surpassed), I don't believe we evolve biologically anymore. That process halted, or at least slowed, when we started changing the environment to suit us, rather than adjusting out lives to adapt to the environment. If it's cold, the hairless cousins dont die off, we just turn up the heat. Hot? the thin-nosed cousins arent at a disadvantage, just turn on the air conditioning. Live in a desert? Don't evolve another way to cool besides sweat to conserve water, just turn on the tap or dig a well. Our technology overcomes the environment (to a degree, the jury is still out on us adapting to micro-organisms.... until the nanites come). This slows evolution.
In essence, if humans (on Earth) have stopped evolving because of technology, and the Engineers already surpass our technology, why would they need Earth to evolve? - They wouldn't.
I think it's obvious the engineers surpass our level of technology - so they are in a similar circumstance regarding evolution. While they may voluntarily surrender their tech to regress to a feral state and evolve, what would be the point? The third generation of offspring would get sick of eating berries and squatting in the mud and start building fires and sharpening sticks. From the human paradigm at least, I don't see the members of any civilization in large numbers voluntarily subjecting themselves to famine, disease, weather extremes, and the food-chain simply for the chance for some beneficial freak mutations to become prevalent in the species several thousand generations later. No one is that altruistic.
Furthermore, even if they can't evolve, the engineers have proven they can force evolution - a la the black goo mutagen and the worms in the face-chamber. If they were worried about evolving, why not just engineer blue goo to transform themselves?
I think they've hit the wall technologically. They can terraform, traverse the stars, and chart the course of evolution on an interplanetary scale. I think they may be looking for some kind of ascension or transcendence, but in the mean time they are just out for new real-estate.
The black-goo combined with the sacrifice breaks down the Engineer DNA into its base proteins - reassembling them into random organisms. Since there's no plant or animal life to eat, plant life survives best at first - "eating" the hostile atmosphere and shitting out a Nitrogen Oxygen atmosphere. Over time animals also evolve, and the engineers move in to their new home.
I think on Earth, despite the extreme odds their species (in humanity) evolved for a second time - only in our understanding we are far behind and our propensity for our reach to exceed our grasp is dangerous. As such, they view humans as a threat to themselves and the galaxy, so they planned on dropping off more goo to cleanse the planet. I think the body-hugger and the end-stage proto xeno are meant to consume and destroy all other life on the planet, then be rendered dormant/be killed off by the Engineers (similarly to how the green crystal seems to control the environment in the chamber with the pots until disturbed by the shore party). In the end, another engineer bites the waterfall and the whole game begins anew.