Well it isn't always survival of the fittest. Any number of advantages can and will be in play.As a general rule, insects and other small creatures have better odds of survival than larger, more complex animals; so it could be expected that the cockroaches would survive, but paleontologist don't have any answers as to why alligators survived while all of the dinosaurs (including marine reptiles like pleiosaurs) went extinct.
Yes we are physically adaptable but I will tell you one thing. Without fire we will die cause we lost that adaptability. That is the only "technology" we need and we managed even through the ice age. In fact we probably wouldn't have survived the ice age without it.We are not much of a physically adaptable species! Our survival and ability to flourish and move into every biological niche on land has come through technology and a high use of energy and natural resources. When those resources dry up, so does our technological advantage.
Right but my point is we don't need an economy to survive so it is besides the real issue. If our populations go beyond our means then populations will simply dwindle until it is again manageable and population will flux accordingly.No, I said that economists and their theories are a source of a lot of our problems, since they depend on us being rational, and their economic models depend on continual growth. They have played a huge part in creating the problems we have today. When we start hitting the limits to further growth, economies fall apart....which they are doing now.
edit: oh and the fire thing is only necessary if we want to remain carnivores.