Evolution of the horse
Videos
The evolution of the horse, a mammal of the family Equidae, occurred over a geologic time scale of 50 million years, transforming the small, dog-sized, forest-dwelling Eohippus into the large, single-
Skeletal evolution
Extinct equids restored to scale. Left to right: Mesohippus, Neohipparion, Eohippus, Equus scotti and Hypohippus.
Restoration of Eurohippus parvulus, a mid- to late Eocene equid of Europe (Museum für Naturkunde, Berlin)
Restoration of Phenacodus
Evidence of common descent
Videos
Evidence of common descent of living organisms has been discovered by scientists researching in a variety of disciplines over many decades, demonstrating that all life on Earth comes from a single anc
Figure 1a: While on board HMS Beagle, Charles Darwin collected numerous specimens, many new to science, which supported his later theory of evolution by natural selection.
Figure 2a: In July 1919, a humpback whale was caught by a ship operating out of Vancouver that had legs 4 ft 2 in (1.27 m) long. This image shows the hindlegs of another humpback whale reported in 1921 by the American Museum of Natural History.
Figure 3a: An insect trapped in amber
Figure 3b: Fossil trilobite, Kainops invius, from the early Devonian. Trilobites were hard-shelled arthropods, related to living horseshoe crabs and spiders, that first appeared in significant numbers around 540 mya, dying out 250 mya.