Teeth are bony formations located on the jaws of many vertebrates, and in some fish, in the pharynx. Initially, the teeth served for protection, but in the course of evolution, another function was assigned to them - the primary processing of food.
Teeth have become an important evolutionary acquisition, with their appearance, the diet of animals has become more diverse. And yet it has never been the same for different groups of living beings. Depending on this, the structure of the teeth also differs. By examining the teeth of a fossil animal, paleobiologists can tell what it ate, because the differences between the teeth of carnivores and herbivores were the same in ancient times as they are now.
Tooth structure
The teeth of any animal are covered with enamel - a special tissue, 97% composed of inorganic substances. Thanks to this, enamel is the hardest tissue in the body and perfectly protects teeth. But even this hard tissue can be destroyed by some chemicals.
There are especially many such substances in plant foods. In order for an animal that eats such food, the enamel layer to survive, it must be very powerful, and the teeth of herbivores are distinguished by just such a feature. For predators, the danger of destroying the enamel is not so great, so there is no need for a thick layer. In carnivores, the enamel layer is much thinner than in herbivores.
However, even a thick layer of enamel does not save the teeth of herbivores from abrasion. Animals would lose their teeth early and die of hunger if their molars, on which the main load falls, would not grow throughout their lives. Enamel could interfere with the growth of teeth, so the molars of herbivores are covered with it only on the sides, and on top, where the tooth is constantly growing, there is no enamel.
Differentiation of teeth
In the course of evolution, teeth have acquired different shapes depending on the function they perform. Four varieties were distinguished: incisors, canines, premolars (small molars) and molars (large molars).
The incisors are located in the front of the jaws. Their purpose is to gnaw or cut food. They are needed in any way of feeding, so all mammals have incisors, but still they play a more important role in herbivores.
In predators, the incisors are short and pointed. In herbivores, these teeth are very diverse. In lagomorphs in rodents, the incisors are long, in the form of chisels, and in ruminants there are only lower incisors, but no upper ones, because these animals do not gnaw anything, they only nibble the grass. The most interesting transformation was the incisors of elephants - they turned into tusks.
Fangs can be called "cutting and stabbing tools." They are designed to tear off pieces of food. Most often this has to be done with meat, so the canines of carnivores are more developed than that of herbivores. The fangs of predators are rather long and sharp, while in herbivores they either resemble incisors in shape, or are completely absent.
The molars (molars and premolars) are used to chew food. Predators chew food very poorly, so they have fewer molars than herbivores. In some herbivores (for example, in cows and horses), the molars are separated from the other teeth by a diastema - a disproportionately large gap. Predators also have diastemas, but they are located in other places: in front of the upper canines and behind the lower ones. Thanks to this, the predator can tightly close its teeth, capturing prey.
It is easy to see that in terms of the structure of the teeth, humans cannot be classified as either predators or herbivores. Differentiation of teeth in humans is not as pronounced as in other animals, all teeth are approximately equally developed. This suggests that man is an omnivore.
