design evidence #320,098,754: the crossover food and air tubes in humans

Nope - you're wrong schraf. The absolute, most perfect, bestest proof of the great Interior Designer of All Life is Rheodytes leukops, the Australian river turtle. Here we have a critter whose cloaca (its butt, for all you comparative-physiology-challenged people out there) not ONLY provides a tube for egg laying, feces and urine elimination, but ALSO, being lined with papillae (like lungs), and fitted with a slight adaptation of the normal "push" musculature, allows the critter to obtain 69% (mean 45%) of its oxygen by pumping water in and out of its anus. What better, more efficient design could you possibly imagine?