"15 ) Explain to me why we donÂ ’ t see humans or dogs or alligators with accidental wings forming . ( If the possibility was there for random mutations to produce wings on reptiles or mammals in the past , then it should also be happening now . )"
"Oh dear ; where do I even start ? Ok , look , the ToE does n't say that the possibility was ever there for random mutation to suddenly make wings appear out of nowhere . It just does n't . The evolution of something as complex as a wing proceeds by a lot of intermediate steps , each one of them being useful , or at least associated with something useful . We do n't see humans or dogs or alligators suddenly sprouting wings because that would require massive wholesale genomic , and probably epigenetic , change . What we do see are more mundane , less drastic variations which can accumulate over time . It 's tempting to think `` wings evolving from arms ; huh , what about the millions of years when they were neither ; how could they have been 'fittest ' ? `` The mistake there is in visualising a straightforward morph from 'then ' to 'now ' , as if the organism knew where it was headed . A better way to imagine it is via an intermediate stage where the arms were still useful as arms , but also conferred an aerodynamic advantage , such as we see in flying squirrels today . If the original purpose of the arms later becomes less important , those features can atrophy while improved aerodynamic qualities remain strongly selected . The divergence of mice and bats is likely to have followed just such a pattern ; who knows , in another ten million years we might see descendents of flying squirrels that are as adept in the air as bats are today . So in a sense , 'flying squirrels ' are your answer . I ca n't guarantee they 'll evolve more and more wing-like structures over the next few million years , but it 's possible ."
"Explain to me why we donÂ ’ t see humans or dogs or alligators with accidental wings forming ."
"The evolution of something as complex as a wing proceeds by a lot of intermediate steps , each one of them being useful , or at least associated with something useful ."