Many of these solutions are about energy minimization. Sometimes its the lifetime energy. Sometimes, its the energy of creation/instantiation. If you start from a bundle of cells you don't have the option to yank a mecanno box of new parts into the system ready-made: you have to use cellular generative methods, to construct largely fluid and jelly filled sacs, which then accrete things, or form surfaces, and you badly want to minimize the energy cost of doing that, within the constraints of the physical system you are in.<p>Whales could be half a mile long and razor. Thin. or globular. They went somewhere inbetween for reasons.<p>Thats what I think, anyway. I base this on (mis) readings of D'Arcy Thompson. 1917.<p><a href="https://en.wikipedia.org/wiki/On_Growth_and_Form" rel="nofollow">https://en.wikipedia.org/wiki/On_Growth_and_Form</a>