Professor Norman: For primitive beings like us, life seems to have only one single purpose: gaining time. And it is going through time that seems to be also the only real purpose of each of the cells in our bodies. To achieve that aim, the mass of the cells that make up earthworms and human beings has only two solutions. Be immortal, or to reproduce. If its habitat is not sufficiently favorable or nurturing, the cell will choose immortality. In other words, self-sufficiency and self-management. On the other hand, if the habitat is favorable, they will choose to reproduce. That way, when they die, they hand down essential information and knowledge to the next cell. Which hands it down to the next cell and so on. Thus knowledge and learning are handed down through time.