I am in the minority here or has anybody ever actually put time into thinking about how Sci-Fi creatures came about? I'm not getting at who thought of them and how but actually say if they were real and not fictional how they evolved or any other factors which made them the way they are.

E.g. The Predator from AvP, I personally think that the Yaucha as they call themselves where probabally once a crustation type species (Big Lobsters if you will) and could have evolved in that fashion to protect itself from a creature higher up on the food chain at that time. According to the books the Yaucha homeworld is a very hot and dry place (if I remember right) and maybe the Yaucha began life as Big Lobsters (hense the mandibles) to protect them from a Sand Shark like creature. Possibly as their intelligance grew they devised ways of avoiding or even slaying these creatures which eventually lead them on their way to being sentient beings and establishing a society. Once they had established ways of hunting instead of foraging they became predators and not prey which may be why they are 'The Big Game Hunters of Space'

My possible explanination is a bit weak and I'm pretty sure someone here could do a better one.

So I'll get the ball rolling, how do you think that the Yaucha came to be and why they turned out that way?

Another good one is why do you think Xenomorphs from the Alien Saga have acidic blood.

Post here ya all.