Perhaps strangely - if you walk through a tropical rainforest, you don't see that much fighting - it all seems rather peaceful most of the time. Nature really likes cooperation.

Are you joking, or are you really that naive? Maybe you should stop talking about evolutionary biology until you've studied it a bit more. Do you have any idea how much of a rainforest is war? That when you look at a tree, the bark is armor against insects that want to eat the tree, the trunk is there to raise it up above other trees that are competing for the same sunlight? If there's anything in a rainforest that isn't at war, it would be a rock.