HOW the peacock got his tail is one of the “Just So” stories of natural history which biologists like to think they have cracked. His tail is for showing off to the ladies (and also to rival males) just how fit he and his genes are. A less than perfect tail means no offspring. Genes for spectacular male tails are thus preserved and promoted over the generations in a process that is called sexual selection.
There is, though, a problem with this story. Peahens, though not as showy as cocks, are by no means dowdy. Their heads have fetching feathered crests, and their necks are a beautiful iridescent blue. Evolutionary logic suggests this is foolish. Such flummery is physiologically costly to grow and is likely to attract predators. If you do not have to strut your stuff to get a mate, why not dispose of it completely?
Even more confusingly, there are many species where both sexes are showy—the Gouldian finches in the picture above, for example (the female is on the right). So, though no one thinks the theory is wrong, as far as it goes, it clearly does not go far enough. To understand things better James Dale of Massey University, in...Continue reading
Source: Science and technology http://ift.tt/1WzSnuw
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