2007-11-29 01:26:07 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Zoology
Through experimentation nature designed pentadactylism.
2007-12-02 17:56:02 · answer #1 · answered by Ishan26 7 · 0⤊ 0⤋
Not all do.
Have you seen a horse with five hooves on each leg?
Some species have five digits, others have four, and so on.
Over time, digits and limbs may disappear.
Whales evolved from four legged land mammals. Whales still have vestigial hind leg bones.
2007-11-29 20:07:40 · answer #2 · answered by Akatsuki 7 · 0⤊ 0⤋
A long time ago we all descended from the same organism. Back then there was probably some environmental pressure which preferentially selected that many digits (this is a gross oversimplification).
Also, the Flying Spaghetti Monster ordained it that way. Ramen.
2007-11-29 09:31:49 · answer #3 · answered by Manny 2 · 1⤊ 1⤋
By chance. We all descend from an comon antecestor with 5 digits. And this design has been proved useful. When this is not the case, some digits are lost.
2007-11-29 09:32:55 · answer #4 · answered by GusBsAs 6 · 1⤊ 1⤋
This is not a perfect rule, but the reason for this homologous characteristics of evolved organisms from a common descendant. EVOLUTION
As Manny stated The Flying Spaghetti Monster made them that way with his noodley appendages. RAMEN
2007-11-29 09:49:10 · answer #5 · answered by Lee S 6 · 0⤊ 1⤋
Fish are vertabrates and so are chickens.
I know for a fact that chickens have only 4 toes on each foot.
2007-11-29 09:29:36 · answer #6 · answered by Anonymous · 1⤊ 0⤋
They do? Wow, I didn't know that. Even reptiles, amphibians, birds, and fish? Cool. I would never have guessed.
2007-11-29 09:29:22 · answer #7 · answered by TopPotts 7 · 0⤊ 0⤋
They Don't.
2007-11-29 12:33:07 · answer #8 · answered by Jungle Jim 1 · 1⤊ 0⤋