[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: origin of bats/reply to J. Headden



When pre-bats became inverted bipeds their hands were no longer involved in locomotory matters. That freed the hands, as in pterosaurs and birds, to become something else. In the case of birds, foldable raptorial instruments and origins for flight feathers. In the case of pterosaurs, foldable display, flapping and gliding instruments.<<

I've lost track of who posted this statement, but it turns natural selection on its head to suggest that the flight feathers of birds and the "foldable" instruments (wings?) of birds and pterosaurs evolved because their hands had nothing else to do. As with other evolutionary innovations, flight feathers and flapping wings are the derived expression of innumerable steps in an undirected process that preferentially selected those random modifications of pre-existing characters that enhanced survival value. If at any point the hands of an animal became essentially irrelevant to survival (i.e., free "to become something else"), it is more likely they would be lost over time rather than being transformed into instruments for flight. The modifications that led to flight in birds, bats and pterosaurs involved much more than just the function of the hands or the feet.


PTJN