I would refer you to the findings of OC Marsh over 130 years ago. Among other things, he traced equine evolution following the transition of horse ancestors to the modern horse (Observation), made predictions and later found fossils missing in the sequence (Testing), and no evidence has been found that did not support the ToE (Falsified).
Ok, So if I draw lines between a Chihuahua and a Great Dane and later find Terriers and Labradors, this is evolution ?
A horse is a horse, big or small, they are still part of the Equine family.