Wilson’s group selection
Genes : Organisms :: Organisms : Groups (:: Groups : Ideas?)
At one end of the scale, quick senescence because cloning a new copy of yourself is safer than defensively repairing the old in face of environmental changes. At the other end of the scale, no obligatory senescence as can keep up with environmental changes by throwing away and/or adding new parts to yourself. Put otherwise, the modularity of a system increases from left to right – the more modular you are, the less ‘you’ (through how many changes are you still you?) need to die in a changing world.