The Evolution of Bird Flight: A Third Hypothesis (English Edition)

Up until now there have been two competing hypotheses about how bird flight evolved. The first hypothesis was that birds were originally animals that ran along the ground on two legs, but failed to adequately explain how and why they developed wings. The second hypothesis suggested that birds were originally animals that lived in the trees and gradually learned how to glide before developing fully-powered flight, but even this theory failed to explain how many of the features of bird flight anatomy evolved within such an environment. However, there is a third way in which bird flight evolution could have evolved, and this hypothesis explains how every aspect of bird anatomy came into being by means of natural selection so that each evolutionary progression provided an edge that allowed birds to survive successfully enough to pass on their genes and eventually conquer our skies.