Given what you know about human activity on our planet, it is possible that we Homo sapiens could start a nuclear or biological war that would wipe out a significant portion of human society, and turn our species into just a small segment of the animal world, no longer dominant in our influence. Should this happen, what type (or types) of organisms do you think might become dominant? What kinds of selective forces might be operating and responsible for this new wave of evolution? Be aware that there is no species in geologic history that has survived from the beginning of life to the present day. Every past species has become extinct. Some become new buds on the evolutionary bush, producing many new branches, while others become dead twigs (like the dinosaurs), that die out and never appear again.