The diagram illustrates the horse’s four steps of evolution during 40 million years, with specific emphasis on the modification of foot structure. Overall, the process consists of four stages, beginning with the Eohippus type and finally becoming the modern type.
Initially, the type namely Eohippus, which lived about 40 million years ago, possesses a tiny shape. The legs first type of horse are noticiable by having some fingers on them. The process continues with a phase changing to the next picture of Mesohippus, which settled 300,00 years ago. Despite the fact that it has not changed materially, the physical apperance experienced a change by increasing height and size, then reducing the count of toes.
On the other hand ,after the Mesohippus type came the Merychippus horse type; the toe structure became more similar to the modern one. 15 million years ago, the evolution was evident in the higher phisique of the hoof-like toe. Finally, after many phases, the process ends with what we can ride a modern horse.