2006-07-10 03:22:33 · 15 answers · asked by jonnny1980 1 in Science & Mathematics ➔ Other - Science
Actually, that is a good question. Our 5-digit limbs that characterize tetrapods were fixed pretty early in the evolutionary history of the group, but not before some "experimentation" like Ichthyostega or Acanthostega, very early tetrapods that had 7 or 8 fingers.
Why was 5 the fixed basic number? Probably there isn't a single answer. The study of the constraints (limitations) that occur during limb development (and may represent "signals" from ancestors) may help to understand why 5 is the rule and why sometimes polydactyly (more than 5 fingers) occurs.
For instance, among mammals, less than 5 toes are frequent among cursorial (running) animals, from rheas and ostriches to deer and horses.But we primates are rather generalized anatomically and most of us have 5 fingers/toes. Being such a well-established part of our body development plan, I guess it would take a rather high selective pressure to change the number. That is, they work, and it could change only if less or more (as some mutations cause) were advantageous.
Interesting paper about constraints:
http://wwworm.biology.uh.edu/evodevo/lecture11/richardson03.pdf
2006-07-10 17:53:38 · answer #1 · answered by Calimecita 7 · 2⤊ 0⤋
Great question!!!! I've been joking (well, half serious) that I'd like to cut off my little toes. They curl under which hurts like heck and with my job we are required to wear heels (at times we change into flats) and have days that are sometimes 14 hours. Could I function with 4 toes on each foot? Has anyone done it with any success? Can you have surgery on your little toes to straighten them? Personally, I don't think we need 5 - they're over-rated!
2006-07-10 03:32:13 · answer #2 · answered by Trix 2 · 0⤊ 0⤋
its apart of the mamalian evolution, that most mamals have 5 toes, including man. Man could run just as fast without the little toe, but 5 toes on ground help u spread ur weight more evenly
2006-07-10 03:32:10 · answer #3 · answered by hardasrock692003 2 · 0⤊ 0⤋
that's just how we are made, but some people have 6 toes or more or less. not everyone has 5 toes
2006-07-10 03:26:34 · answer #4 · answered by lulucakes32 5 · 0⤊ 0⤋
More toes or less toes didn't give any survival advantage so those mutations were eliminated from the gene pool by natural selection.
2006-07-10 03:47:23 · answer #5 · answered by Anonymous · 0⤊ 0⤋
believe it or not our body has its own symmetrical way of developing .. we have five fingers which are helpful similarly that symmetry can be seen on our foot. 5 toes have nerves going in and out of our heart connected ot whole body.
2006-07-10 03:29:09 · answer #6 · answered by browneyes 2 · 0⤊ 0⤋
5 is the perfect number to help us keep our balance. Any more and they'd just get in the way. Any less and they'd be too big and unwieldly.
2006-07-17 03:26:01 · answer #7 · answered by Garfield 6 · 0⤊ 0⤋
i choose not to argue with evolution mechanism..
we are the living proof that this 5 fingers very usefull
if they are not, individual with 5 fingers will eventualy perish..
instead of that, individual with less or more finger does not multiple much in our world :)
see?
2006-07-10 03:38:18 · answer #8 · answered by deval_agrifarman 6 · 0⤊ 0⤋
Yes, eveything God make's is the best it can be !
three would be to little an six + would be too much !
Five is just rite : )
2006-07-10 03:28:50 · answer #9 · answered by cingular11111 2 · 0⤊ 0⤋
it's all about stability. maybe in time they will clump together but nature wants a stable design
2006-07-10 05:06:44 · answer #10 · answered by shiara_blade 6 · 0⤊ 0⤋