Ageing Horses By Teeth
How many horses have come to be?
The evolutionary history of the horse is one of the most popular topics in modern biology. And no wonder – all modern animals, the horse has behind her the most intact and visible tree.Our family story begins millions of years ago – with Perissodactyla.
No, no "pterodactyl" – the relics of flight of the dinosaur age claw imagined in B-movies and The Flintstones. The Perissodactyla "are animals hooves an odd number of toes on each foot (which is also distinguished by their tooth structure), this group of animals is in itself, scientists say, the descendants from a common ancestor as the tapir and the rhinoceros, but, unlike these animals gradually adapted to life on earth than the tropical dry forests preferred Even today, the rhinoceros.
A child development often influences the other creatures in their environment, and so did the horse (the horse industry Perissodactyla family tree), which began eating grass like the new crop began to flourish. Such a diet favored the spread of new types of horses he had big teeth.
Similarly, horses – the adoption of a dry habitat, steppe, where predators lived and the relative lack of foliage become more difficult to hide, he encouraged the survival of the horse, who ran the fastest. Little by little, the horses and legs with long toes third (which allowed for more efficient running) began to predominate. Mesohippus species 40 million years reflect this trend.
It is a mistake common – but disastrous – to show the evolutionary history as a straight-line smooth progression from early to mid-modern versions of an animal, with modern animal taken as the final copy of the earlier draft animals' raw, as if we were seeing successive drawings of Michelangelo's David in a row that ended with the real statue.
In fact, however, most of the equine species lived his life and died without having any influence on the horse today, but there own right, and we should not think of the modern horse as the "goal" of all this living and dying horse. Many lines of descent just came out running, while one (leading to our horse) lucky enough to survive, but may well have been any or all of the other, taking into account light changes in some habitat of a million years or so.
In any case, horselike the many species whose fossils have been found, is thought that Plesippus – a species descended from earlier Dinohippus – is the father of the modern horse. This species responds to falling temperatures in North America by starting either South America or in the Bering Strait from North America to Eurasia, about 2 million and a half years, stayed behind in America North.
Somewhere toward the end of the Tertiary or early Quaternary – Talking to the scientists for the beginning of the last Ice Age, About 1.8 million years – the descendants of offspring resulted Plesippus quite different from their sponsors, and as sufficient for modern horses, which scientists have called stenonis Equus, the first "real" horse.
They entered North America and survived for millions of years, perhaps giving rise to the other old horses are known to inhabit the area during this period – the Equus giganteus scottii large, whom the author swears that is not making up (which appear to have exceeded the size of modern horses.) However, all North American horses died out, and inexplicably, 11,000 years ago – at the very moment that many other types of animals, for reasons scientists have yet to discover. "It was a mega-virus the ancient world? O However, a more tempting possibility, not humans (arriving on the scene in North America, according to some theories, at about this time) to hunt extinction?
In any event, the horses had no purchase on this continent until after the European colonization of the Americas began in 1492, for long period of time, then, of 11,000 a. C. to 1491, the development of the horse is held in place in Eurasia. (Another tempting idea – after settlers had reintroduced horses to Mexico, the southwestern U.S. and Peru, some Indian tribes told stories about how "the grass remembers" these new animals.
Are these groups of people who retain some memory, perhaps through the myth and legend, of the now defunct American horse North?)
The outline of the history to horse given here is only a sketch, based on a chapter of scientific theorizing. Perissodactyla Like former giving rise to many species of not-quite-a horse, most of which flourished in his time and died without contributing to the development of horses modern scientific speculation about the origin of any species include many interesting and intelligent ends "dead." So who knows.
One popular theory, the "Four Fundamentals of theory, suggests that at some point before the disappearance long the horse in North America, four basic types of horses developed in Europe (of Plesippi, perhaps, who crossed from North America to Eurasia before the last ice age began.) Warm-blooded horses live in forests and draft horses of northern Europe, taller, thinner horses and pony Tarpans Asia in size, are considered, in this theory, to be the "base" horses which all others have the same origin.