horse evolution - west virginia universitypages.geo.wvu.edu/~kammer/g231/horses.pdf · horse-zebra...
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Ungulate ToesUngulate Toes
Artiodact ls: Perissodact ls:Artiodactyls: even-toed
Perissodactyls: odd-toed
Bovine and swine Horse and rhinocerasBovine and swine Horse and rhinoceras
Horses reduced their toes from five to one, while also lengthening the , g gbones, during their evolution.
Evolutionary trends in horses andEvolutionary trends in horses and many other ungulates
• Reduction in toes• Elongation of legs by standing on the toes• Increased body size• Elongation of the muzzle• High crowned specialized teeth• High crowned, specialized teeth
Environmental Causes of Evolutionary trends in horses and
many other ungulatesmany other ungulates• Need for greater speed and body size to
escape predatorsescape predators.• Cooling climate during the Cenozoic
replaced forests with grasslands Simplereplaced forests with grasslands. Simple hooves and elongated legs are adaptive for running in the open. Elongated muzzle to u g e ope . o g ed u e oreach grass.
• Grasses are high in silica. High crowned g gteeth are adaptive.