Phylogenetic series of horses - "icon" of the evolutionary process

One of the most famous and most studied of paleontological evidences of evolution is the phylogenetic series of modern single-fingered ungulates. Multiple paleontological finds and identified transitional forms create a scientific evidence base for this series. Described by the Russian biologist Vladimir Onufrievich Kovalevsky as far back as 1873, the phylogenetic series of the horse still today remains an "icon" of evolutionary paleontology.

Evolution through the ages

In evolution, phylogenetic series are successive successive transitional forms that led to the formation of modern species. The number of links may be complete or partial, but the presence of successive transitional forms is an indispensable condition for their description.

The phylogenetic series of a horse is attributed to evidences of evolution precisely due to the presence of such successive forms replacing each other. The multiplicity of paleontological findings gives it a high degree of certainty.

Examples of phylogenetic series

A number of horses are not the only one among the examples described. A well-studied and highly reliable phylogenetic series of whales and birds. A controversial in scientific circles and the most used for various populist insinuations is the phylogenetic series of modern chimpanzees and humans. Disputes over the missing intermediate links do not subside in the scientific environment. But no matter how many points of view, the indisputable remains the importance of phylogenetic series as evidence of the evolutionary adaptability of organisms to changing environmental conditions.

Relationship of the evolution of horses with the environment

Multiple studies of paleontologists confirmed the theory of OV Kovalevsky about the close relationship of changes in the skeleton of the ancestors of horses with environmental changes. Changing climate led to a decrease in forest areas, and the ancestors of modern single-fingered ungulates adapted to the conditions of life in the steppes. The need for rapid movement provoked modification of the structure and number of fingers on the limbs, a change in the skeleton and teeth.

The first link in the chain

In the early Eocene, more than 65 million years ago, the first modern horse of the modern horse lived. This "low horse" or Eohippus, which was the size of a dog (up to 30 cm), rested on the entire foot of the limb, which had four (front) and three (rear) fingers with small hoofs. Eat eogippus shoots and leaves and had tuberculate teeth. Bulan coloring and rare hair on the movable tail - such is the distant ancestor of horses and zebras on Earth.

Intermediate links

About 25 million years ago, the climate on the planet changed, and the forests were replaced by steppe expanses. In the Miocene (20 million years ago) mesohypus and parahhipus appear, which are more similar to modern horses. And the first herbivorous ancestor in the phylogenetic series of horses is considered to be merikhippus and pliogippus, which enter the arena of life 2 million years ago. Hipparion - the last three-toed link

This ancestor lived in the Miocene and Pliocene on the plains of North America, Asia and Africa. This three-fingered horse, reminiscent of a gazelle, did not yet have hoofs, but could run fast, eat grass and it took up huge areas.

One-fingered horse - pliogippus

These single-fingered representatives appear 5 million years ago in the same territories as the gipparions. Environmental conditions change - they become even drier, and the steppes grow considerably. Here and there was a single-fingeredness more important sign for survival. These horses were up to 1.2 meters high at the withers, had 19 pairs of ribs and strong leg muscles. Their teeth acquire long crowns and folds of enamel with a developed cement layer.

A horse we know

The modern horse as the final stage of the phylogenetic series appeared at the end of the Neogene, and at the end of the last glacial period (about 10 thousand years ago) millions of wild horses already grazed in Europe and Asia. Although the efforts of primitive hunters and the reduction of pastures made the wild horse a rarity already 4 thousand years ago. But its two subspecies - tarpan in Russia and Przewalski's horse in Mongolia - managed to hold out much longer than all the others.

Wild horses

Today, there are practically no real wild horses. The Russian tarpan is considered an extinct species, and Przhevalsky's horse is not found in natural conditions. Herds of horses that graze freely are wild, domesticated forms. Such horses, though quickly returning to the wild life, but still different from the truly wild horses.

They have long manes and tails, and they are different. The exceptionally pruned Przewalski horses and mousy tarpans have, as it were, trimmed bangs, manes and tails.

In Central and North America, wild horses were completely exterminated by Indians and appeared there only after the arrival of Europeans in the 15th century. The wild descendants of the horses of the conquistadors gave rise to the numerous herds of Mustangs, whose numbers are now controlled by shooting.

In addition to the Mustangs in North America, there are two species of wild island ponies - on the islands of Assatig and Sable. Semi-wild herds of camargue horses are found in the south of France. In the mountains and swamps of Britain, you can also meet some wild ponies.

Our Favorite Horse

The man tamed the horse and brought out more than 300 of its breeds. From heavyweights to miniature ponies and handsome racehorses. In Russia, about 50 breeds of horses are bred. The most famous of them is the Oryol trotter. An exceptionally white suit, excellent lynx and quickness - these qualities were so appreciated by Count Orlov, who is considered the founder of this breed.