Just for fun:
"According to Darcy Thompson [2] the appearance of Fibonacci numbers in biology is not due to some mysterious force. It can be accounted for by “the action of forces that lie in the steady production of similar parts, similarly situated, at similar successive intervals of time, and in consequence this gives rise to symmetrical patterns depending on the form of the entire surface.” "
http://file.scirp.org/Html/4-8301619_18625.htm