S: MY HORSY BOOK
FC: Evolution of the Equine By: Mason Bogowitz | Oct. 1 2011 | Horsies!!!!
1: "The Skeleton of a Hyracotherium | For a long time it was thought that the equine or the Horse as we know it had a fairly simple evolution tree. This however was proved to be larger and not straight. The first known ancestor of the equine is thought to live during Cenozoic Era, early Eocene. It was called the Hyracotherium.
2: The Hyracotherium was 10-20 inches tall. The legs where flexible and had 4 toes on each front foot, 3 on the back feet. It also had a very small brain low crowned teeth with 3 incisors, 1 canine, 4 distinct premolars and 3 "grinding" molars in each side of each jaw. It lived during the early Eocene period. A species very successful in its time. | A drawing of what the Hyracotherium was thought to look like.
3: The skeleton of a Orohippus, you can see the similarities between it and the Hyracotherium as their skeletons are very similar. | During the end of the early and the middle Eocene period a new species arose called, Orohippus. Not much difference here but it did have some.
4: While the differences between Orohippus and Hyacotherium where few, there was still some. For one while Orohippus still had 3 and 4 toes the vestiges of the 1st and 2nd toes vanished. The main difference however was that the last premolar changed in shape to become like a molar, also the crests on the teeth were more pronounced which meant that it was eating tough plant material. | A drawing of what Orohippus was believed to look like
5: Epihippus was the next step in the evolution chain. It was just like the other previous species but its teeth continued to change. The last of the premolars became molars. | A drawing of what Epihippus was thought to look like
6: At this point in time the world began to change. It was the beginning of the Oligocene period and the large forests began to shrink and grass began to rule. The new species of Horse started with the sudden appearance of Mesohippus | The skeleton of a Mesohippus, it can be seen how the horse is beginning to lose its dog shape.
7: The Mesohippus had a larger series of changes. Firstly it had lost its dog shape somewhat, its back was slight less bent and its legs where longer. Secondly it now had 3 toes on its front and back feet. Lastly its cerebral hemispheres where much larger and it now had 6 grinding teeth instead of 5. | A drawing of Mesohippus. As you can it does look more like the horse we know today.
8: The next stage is the Miohippus. After Mesohippus died out Miohippus took over. Miohippus had a slightly longer skull, was slightly larger and it had a extra crest in its upper cheek teeth, Also its ankle joint was slightly different. | A drawing of a Miohippus, from the drawing you can see the slightly different skull.
9: The Third step in the evolution of the Equine starts at the beginning of the Miocene era. It began to grow more accustomed to the growing presence of grass as can be seen in the evolution of its teeth and how it became for geared toward running.
10: The first step in this new stage is the Parahippus which showed some differences. The main changes however where in the teeth which where stronger tooth crests and larger tooth crowns, it was also slightly larger than a Miohippus. | A drawing of Parahippus, it shows the difference in the mouth.
11: The Merychippus was a much larger species, standing at about 40 inches tall. It also had a more elongate muzzle, the jaw mas deeper and the eyes moved back. It also was still three toed but was spring-footed, it stood on tip toe and tis central toe had a formed a sort of hoof. Its teeth showed change to in that it was fully high crowned and thickly cemented. | A drawing of Merychippus that shows how it looks the most like a modern Equine so far.
12: The last stage of the equine evolution is the one toed species. It all happens around the Late Miocene, Pliocene & Pleistocene eras.
13: The first species is the Pliohippus which at first had 3 toes but gradually lost them. It was thought for a while to be the direct decedent of the Equus but it was later show to not be true when two main differences where discovered. First it had a deep facial fossae and secondly it had curved teeth where as the equus had straight teeth. | A drawing of the Pliohippus, can really see the similarities between it and the modern Equus.
14: Dinohippus is the ancestor of the Equus as can be seen by the gradual decrease in the facial fossae, straightening of the teeth. | a very pretty drawing of the Dinohippus in which you can see it looks almost exactly like the Equus.
15: Finally we get to the final destination, the Equus. The Equus iis 13.4 hands tall and has one toe with side ligaments., the brain was slightly larger than Dinohippus. | Picture of a Horse goes here but Mixbook was being dumb and won't let me add it.
16: http://www.talkorigins.org/faqs/horses/horse_evol.html http://www.talkorigins.org/faqs/horses/horse_evol.html http://dinosaurs.about.com/od/dinosaurpictures/ig/Pre http://www.zum.de/Faecher/Materialien/beck/13/pferd.htm http://www.diggwallpapers.com/DesktopWallpapers/1093/Horse-3/1280/768/
17: http://www.digitaldesktopwallpaper.com/downloads/animal_wallpaper_007.htm http://www.free-pet-wallpapers.com/Free-pet-wallpape.com http://www.sharktoothhill.org/images/horse.jpg http://www.risingstarfarm.net/horse%20photos/ancestors/landgraf.jpg http://www.mypets.net.au/upload/flex_img/large_16112008064032_347.jpg http://0.tqn.com/d/dinosaurs/1/7/9/B/-/-/AMNHdinohippus.jpg http://chem.tufts.edu/science/evolution/HorseEvolution.htm
18: http://www.cleanvideosearch.com/media/action/yt/watch?videoId=e_t9nnp7rHk | Go to this site i i i i V | Get ready for you mind to be blown!!!!!!!!
22: A Picture is Worth 1,000 Words
23: Cherish The Ones You Love
30: How Sweet It Is To Be Loved By You! | Live well, laugh often, love much
32: "He holds her hand,She holds his heart."
33: To the world you may be one person, but to me you are the world.