Waarom heeft een eend oranje poten?

Misschien is dat om haaien op afstand te houden wanneer ze zwemmen? Felle kleuren in de natuur zijn immers vaak om roofdieren af te schrikken

[Dit bericht is gewijzigd door KillerRabbit op 11-03-2003 22:32]

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Op dinsdag 11 maart 2003 22:30 schreef calvobbes het volgende:
Wat is het nut van roze flamingo's?

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[Dit bericht is gewijzigd door poentje op 11-03-2003 22:32]

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Q: Why are a duck's feet coloured orange?

A: Ronald Ydenberg answered on April 19, 2000:

A famous evolutionary biologist once said of a particular bird species with bright red males and green females that he would be ready to die once he understood completely why this was so. Of course this means that the answers to these questions are not fully understood - and scientists really want to know.

The first thing to note is that not all ducks have orange feet. However in many species of ducks and other birds the feet are bright orange, red, or yellow. The physiological reason for the coloration is the skin contains carotene and related compounds. The question is: why carotene, making the skin orange, rather than another compound that would make the skin a different color?

The answer seems to have to do with the attraction that these traits hold for members of the opposite sex. In some species orange (or red, blue or yellow) feet (or heads, wings, beaks, etc.) perform this function, while in others it is wattles, combs, inflatable throat pouches, loud noises, long tails, special feathers, metallic-colored spots, extravagant displays, and smells. These traits seems to have evolved because they have power to attract mates. Lots of work has amply demonstrated this to be true in many species in a variety of interesting ways.

Soometimes it is clear WHY potential mates find these traits attractive. In crickets, for example, females have to locate males and do so by the loud songs males make. But why would a female like orange feet more than say flesh-colored feet?

One idea is that the traits are arbitrary; they evolved because (for example) females in a population happened to develop a preference for brighter wattles. If females had such a preference, brighter wattles would confer a mating advantage to males that had them, even if the reason for the preference was completely arbitrary. The idea works in theory, at least.

And it is known that males of some species (e.g. zebra finches) can be made really sexy by fitting them with colored leg bands or even bizarre colored head ornaments - features which seem pretty arbitrary!

If females like a particular male trait NO MATTER WHY OR HOW, males with that trait are selected for. But, could the preference for the trait have some basis? For example, could the trait reveal individual quality or ability in some way (e.g. parasite resistance, or high suitability for the local environs)? Male ducks with bright orange feet may be showing that they are better able to resist the parasites and diseases found in a region, and that if the females want ducklings with the best genes for parasite resistance, he's the guy. Alternately, the bright orange feet may reveal that the male is good at foraging (carotene comes in the diet), or better able to elude predators, or better able to care for offspring.

It is proving pretty difficult to disentangle all the factors that may operate in natural populations, and ecologists don't know for sure which (if any) of these ideas are correct. A big picture of the puzzle still seems to be missing. But work is continuing, and lots is published on this question in the scientific literature each year.

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Nou, daarom dus.

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Op dinsdag 11 maart 2003 23:03 schreef The_Lizard_Queen het volgende:

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Van: http://www.science.ca/askascientist/viewquestion.php?qID=165

Nou, daarom dus.

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Op dinsdag 11 maart 2003 23:03 schreef The_Lizard_Queen het volgende:

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Van: http://www.science.ca/askascientist/viewquestion.php?qID=165

Nou, daarom dus.

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Op dinsdag 11 maart 2003 23:20 schreef MissMSX het volgende:

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Tijd om naar bed te gaan... zit onder verkeerde user te posten

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Op dinsdag 11 maart 2003 23:24 schreef Pardonlul het volgende:

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Wat is het verschil ?

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Op dinsdag 11 maart 2003 23:24 schreef Pardonlul het volgende:

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Wat is het verschil ?

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[Dit bericht is gewijzigd door Bluezz op 11-03-2003 23:42]

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Op dinsdag 11 maart 2003 22:30 schreef KillerRabbit het volgende:
ik denk dat ze erg koningshuisgezind zijn....

Misschien is dat om haaien op afstand te houden wanneer ze zwemmen? Felle kleuren in de natuur zijn immers vaak om roofdieren af te schrikken

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Op dinsdag 11 maart 2003 23:41 schreef tRiZzZ het volgende:

ik dacht dat eenden voornamelijk in vijvers en meertjes en sloten zwemmen, maar dus ook op zee waar haaien zwemmen

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[Dit bericht is gewijzigd door Bluezz op 11-03-2003 23:45]