Imagine a school of fish or a flock of birds. Notice how they seem to move in a fluid motion almost in unison? How is it that when one fish moves in one direction to avoid a predator or obstacle, the others seem to follow? Each individual animal is after their own preservation - so when one spots a predator or obstacle it moves out of the way, that results in a subtle cue to the rest of the group to do the same. A single action triggered by one animal can result in a large change that benefits the entire group. The flock becomes an organism.