ID The Evolution of Horse

Recently i have been doing a project for one of my classes that involves evolution. I chose horse. The horse family known as the equidae first emerged in North America 55 million years ago and has evolved over time. Nearly all of these diverse horses extinct over time. In this present day the Equidae family, which also included zebras and donkeys, only has seven different species. 35 million years ago the climate began to change the wet forests in North America to dry grasslands. This change affected horse evolution. Present day horses show many adaptations to the plains habitat. I.E.- Early horses had 3 or 4 toes, each ending in a small hoof. But those horses with bigger stronger, middle toes were better adapted to run on and walk on dry, hard ground. Natural selection led to the near disappearance of the side toes, while the middle toe and its hoof became gradually bigger.


Also, Each breed has a different trait such as body size and skeletal conformation to enhance the horses marketability, soundness, function and their performance. to identify a horses, professionals use 35 measurements to identify and determine skeletal variation in the horse. Professionals measured 1215 horses and determined 65 breeds of diverse types such as Arabic horse, shire, shetland pony, thoroughbred, american miniature, clydesdale.