Why does a man five fingers Bashny.Net

Successful chisloU human hands and feet with five fingers, because it is so much the fingers were monkeys from which we come and apes inherited the five-fingered limbs from their ancestors, and so on, up to ancient amphibian that lived 300 million years ago. It seems that the common ancestor of all modern land vertebrates had five-fingered limbs. In other words, five-fingered limb - is primitive, the original structure of the limbs of all terrestrial vertebrates. In most species, including humans, this structure has survived to this day.





Some vertebrates have decreased the number of fingers or even their total loss, sometimes with themselves limbs. This usually happens in those animals, which for some reasons, some fingers begin to interfere, became "superfluous." For example, the ancestors of the horses on the middle finger has developed a large hoof, he greatly increased his finger and other fingers became unnecessary, they only hinder the growth of the middle finger, and gradually disappeared. In human ancestors probably did not arise such situations to some fingers become "unnecessary." So they, and all survived.

The issue, therefore, boils down to why the common ancestor of all modern land vertebrates limb was just five-toed. Scientists today believe that there are no special reasons for this was not. Five-fingered limb does not have any fundamental design advantages over a four- or six-fingered. Apparently, five-fingered entrenched in vertebrate evolution is purely coincidental.

Among the earliest fossil tetrapods as found by paleontologists to have been shaped with a different number of fingers: for example, Ichthyostega had seven toes on the hind legs (front did not survive), we Acanthostega had eight toes on the front legs and at least as much - on back . Legs evolved from fins fish fingers - from the rays of the fins, and the number of fin rays in those fish, from which the terrestrial vertebrates, it was choppy.

Apparently, the ancient terrestrial tetrapods number of toes, too varied. By chance it so happened that it gave rise to five-fingered shape around the diversity of today's pets and animals with a different number of fingers extinct. But they became extinct, probably not because they had the wrong number of fingers, and for some quite different reasons, in connection with which the other, more significant "shortcomings" of its structure. In principle, it could be "lucky" not five digits, and, say, semipalym ancient amphibians. And then, maybe, people now would be seven fingers.

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