contingent

hair follicles' and sweat glands' fates are chained
the same progenitors make either cell
selecting better cooling for big brains
our ancestors got hairlessness as well
four times--at least--the flapping wing's evolved
however inefficient 'tis for flight
the menu's fixed and Darwin merely solved
for something that would work, 'though it's a fight
a screw-propeller wasn't in the cards
for multicellulars like you and me
and Reynold's numbers make the flying hard
flagella only work when they're at sea
this time, a primate triumphed through the odds
another cast of dice....cephalopods?