There are several obvious, opposing forces at work for selecting the number of fingers:
1. More fingers are useful for grasping things. That increases your ability to survive and produce offspring.
2. More fingers snag, get injured, and lose heat. That decreases your ability to survive and produce offspring.
When opposing forces meet, there is an equilibrium position. That position for Humans is 5.
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Anonymous2008-10-07 23:51
>>7
Cute, but wrong. The number of fingers in humans isn't an adaptation, it's an accident of history. Fins had five bones, just because.
The panda's thumb, on the other hand, is an adaptation.
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Anonymous2008-10-09 20:24
>>8
"Just because" What, the fuck. No.
That's a retarded statement.
>>9
Not really. There's no significant advantage to having five digits compared to four or six, but you have to have some to support the fin, and it happened to settle on five. An accident of history.
There are four and six-armed sea stars, you know. We should make them fight and see why the five armed one wins. I'm betting it gives an advantage when doing the Texas piledriver.
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Anonymous2008-10-10 19:06
>>12
I know the Crown-of-thorns starfish can have 12-19 arms. They're becoming a real problem in coral reef ecosystems. They're like locusts. Since they're breeding so well, more arms must be an advantage, right?
Oh wait. They're also covered in poisonous spikes and so have no natural predators (except for the armies of pissed off scientists who are attempting to keep them for destroying the most diverse aquatic ecosystems on the planet).
That's about all my knowledge on starfish, but following a link at the top of that article goes to the giant sunflower starfish with 26 arms.
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Anonymous2008-10-10 19:47
>>13
You'd think an army of pissed of scientists would be a powerful enemy, but they're no match for a bunch of starfish. The Gordon Freemans of this world are few and far between, I guess.
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Anonymous2008-10-10 19:48
More arms for the starfish equates to higher survival ability.
EoS.
>>14
Gordan Freeman can take on any headcrab that comes his way, but he can't remove the entire headcrab infestation, of even say, Ravenholm.
>>12
4 armed starfish? I've never heard of that. Example?
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Anonymous2008-10-10 21:59
>>16
Well I'm not sure if there's a properly four-armed species, but an image search should net you some individual examples, which is good enough for the purposes of a Darwinistic death match.
That mutations causing more or less arms do appear to be a relatively common occurence suggests that there is indeed some evolutionary advantage of having a full poker hand.