EPOW - Ecology Picture of the Week

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A Tale of Four Wings

Credit & Copyright: Dr. Bruce G. Marcot

Explanation:  What on Earth do these four creatures have in common ... an extinct Archosaur, a bumblebee, a cormorant, and a bat ... ?  The simple answer is obvious ... they all fly.   But less obvious is the fact that independent flight has evolved on Earth four times, in completely separate classes of organisms:  pterosaurs, birds, mammals (bats), and insects.  This "tale of four wings" (OK, actually eight wings) represents how adaptation sometimes results in similar or convergent "solutions" to problems.   So what problems has the power of flight solved?  Consider this list:  escape from terrestrial predators ... efficient movement to areas with better food sources or better weather ... ability to occupy niches otherwise unused ... ability to use resources otherwise unexploited ... more efficient finding of mates ... more efficient dispersal from natal areas ... and the list could go on.  What advantages might each of the above animals have, in being able to fly? There had been some debate over whether pterosaurs actually had independent flight or if they just were able to glide.  Gliding has evolved in a number of animal groups including squirrels, possums, snakes, frogs, geckos, and others, most likely as a predator-escape response.   And maybe we should add Homo sapiens to the list of species in which both flight and gliding have developed!  This makes humans the "Fifth Wing."