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Well, how can you say that a dove's wing is not the perfect wing for the dove ? I mean surely if 1 dove develops a mutation to produce a better wing (faster/longer flight), this would assume that the 'fitter' dove would have a greater chance of surviving to reproduce ? Thus after x years of mutation, the dove would have a perfect wing (for its body) ?
Yes, and no. The dove will develop a wing that best balances the many trade-offs involved in a doves life. The wing must produce enough thrust, lift, manouverability (sp?) to meet both it's food gathering, and predator escape needs (note that to escape a predator it doesn't need to be faster than the predator, only faster than the slowest dove). But it must also have as low as possible a food cost, both in terms of construction, maintanence and energy to use. It must be durable, but light. And so on, across a whole range of factors.
So the dove will evolve a wing that balances the required factors to best increase it's reproductive chances. Note that it (probably) can't actually reach the best possible wing design to match these criteria because it has to move by small 'step-wise' change, each of which must be viable.
Evolution rarely produces the 'best possible' anything, because the extra ability granted by 'best possible' is rarely worth it's biological cost.
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