The history of horse evolution is one of the most-the issues addressed in modern biology. And no wonder – of all modern animals, the horse has If the family behind the most intact and visible tree.Our story begins millions of years ago – with the Perissodactyla.
No, not "pterodactyl" – Flight claws relics from the era of the dinosaurs as imagined in B-movies and the Flintstones. The "Perissodactyla" are hoofed animals with a number odd toes on each foot (which is also distinguished by their tooth structure), this group of animals is in itself, scientists say, are descended from the same ancestor as tapir and the rhinoceros, but, unlike these animals gradually adapted to life in drylands favorite tropical forests, even today, the rhinoceros.
A creature of evolution often influences the other creatures in their environment, and this is true of horses (the branch of the family tree Horsey perissodactyl) who began eating grass like the new crop began to flourish. Such a diet facilitated the spread of new types of horses that had big teeth.
Also, horses, – the adoption of a dry, steppe-like habitat where predators lived and the relative lack of foliage made it difficult to conceal, encouraged the survival of the horse, who ran the fastest. Gradually, longer-legged horses with a third toe length (allowing greater operational efficiency) began to predominate. Mesohippus species 40 million years reflect this trend.
It is a common – but disastrous — wrong to see evolutionary history as a good step forward in a straight line from early to mid-modern versions of an animal, with the modern animal taken as the final copy of the earlier draft animals, as if we were seeing successive drawings of Michelangelo's David in a line that ended with the actual image.
In fact, however, Most species of horses once lived and died without having any influence on the horse today, exist in their own right, and we should not think in the modern horse as the "goal" of life all this sickness and death. Many genealogical lines simply ran away, while one (leading to our horse) that happened to survive, but may well have been any or all of the other, given some slight changes in habitat for a million years or so.
In any case, the many equine species whose fossils have been found, is thought to Plesippus – a sort of descendant of the previous Dinohippus – Is the father of the modern horse. This species responds to falling temperatures in North America by starting either South America or the Bering Strait from North America from Eurasia, about 2 ½ million years ago, stayed behind in North America.
Somewhere toward the end of the Tertiary or early Quaternary – you're talking to scientists for the start of the last Ice Age, approximately 1.8 million years – Plesippus descendants led to the descent sufficiently different from their sponsors, and as sufficient to modern horses, which scientists have called stenonis to Equus, the horse "real" first.
They crossed into North America and survived for millions of years, perhaps bringing the other old horses are known to inhabit the area during this period – that large scottii Equus giganteus, whom the author swears that is not to invent (which seem to have passed modern horses in size). However, all North American horses died out, not inexplicably, some 11,000 years ago – at the same time as many other types of animals, for reasons scientists have yet to discover. Was it a mega-virus of the ancient world? Or, a more tempting possibility, non-humans (who come to the American scene, according to some theories, at this time) hunting for extinction?
In any case, horses do not buy on this continent until after European colonization of the Americas began in 1492, for long period of time, then, from 11,000 BC to the 1491, development took place in Eurasia horse instead. (Another tempting idea – after the settlers had re-introduced horses to Mexico, the region American Southwest and Peru, some Indian tribes told stories about how the grass, "recalls the" these new animals.
Do these groups of people who keep the memory, perhaps through the myth and legend, of the now defunct North American horse?)
The outline of the horse story told here is only a sketch, based on a shred of scientific theorizing. Like the old Perissodactyla leading to many species of not-quite-a-horse most of those who flourished in his time and died without contributing to the development of modern horses, scientific speculation about the origin of any species include many interesting topics, intelligent impasses. " So who knows.
A popular theory, the Foundations 'Four' theory suggests that at some point, long before the demise of the horse in North America, four basic types of horses developed in Europe (from the Plesippi that, perhaps, who crossed from North America to Eurasia before the last ice age started). The forests of warm-blooded horses and the proposed housing horses of northern Europe, taller, slimmer Asian horses and ponies tarpans size are considered, in theory, be the "foundation" horses from which all others are descended.
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