"Locating Life's Limits with Dimensionless Numbers"
Despite the dazzling diversity of life, evolution hasn't
complete freedom - it's constrained by such matters as basic physical rules
and the conditions on earth. Borrowing a page from the engineers,
it turns out that dimensionless numbers, both well-established and newly-contrived,
can give us a lot of help in understanding what nature
can and can't get away with. The insights they provide apply to,
among other things, locomotion, respiration, and circulation.