Question

Explain (in essay format) how the dentitions and digestive systems of mammals differ and allowed the diversification of mammals

Answer 1

Teeth is made up of enamel and it is the hard white structures in the mouth. Usually used for mastication, the teeth of different vertebrate species are sometimes specialized. The teeth of carnivorous mammals, such as cats and dogs, are more pointed than those of primates, including humans; the canines are long, and the premolars lack flat grinding surfaces, being more adapted to cutting and shearing (often the more posterior molars are lost). On the other hand, herbivores such as cows and horses have very large, flat premolars and molars with complex ridges and cusps; the canines are often totally absent. Sharp pointed teeth, poorly adapted for chewing, generally characterize meat eaters such as , dogs, and cats; and broad, flat teeth, well adapted for chewing, characterize herbivores. The differences in the shapes of teeth are functional adaptations. Few animals can digest cellulose, yet the plant cells used as food by herbivores are enclosed in cellulose cell walls that must be broken down before the cell contents can be exposed to the action of digestive enzymes. Consequently, chewing is not so essential for carnivores as it is for herbivores. Humans, who are omnivores (eaters of plants and animal tissue), have teeth that belong, functionally and structurally, somewhere between the extremes of specialization attained by the teeth of carnivores and herbivores.

Each tooth in the mouth consists of a crown and one or more roots. The crown is the functional part of the tooth that is visible above the gum. The root is the unseen portion that supports and fastens the tooth in the jawbone. The shapes of the crowns and the roots vary in different parts of the mouth and from one animal to another. The upper teeth differ from the lower and are complementary to them. Humans normally have two sets of teeth during their lifetime. They are milk teeth and permanent teeth

The sharp teeth of carnivores are used for cutting and slicing foods, whereas the washboard-like molars of some ruminants are used for grinding food for a wide-ranging survey of mammalian teeth). Primates do not exhibit the entire range of variation of mammalian tooth shape, but, since teeth are the most common items in the primate fossil record, they have had a huge influence on inferences about primate paleobiology. More generally, the size of the incisors seems to be a reasonable indicator of the frequency and complexity of ingestive behaviors, rather than a simple correlate of differences in traditional diet categories such as folivory and frugivory.In herbivores, particle size reduction has a momentous influence on the rate of digestion , and the ability to reduce ingesta particle size is therefore typically considered a prerequisite for the high energy intake rate required to fuel endothermy .Across mammals, this is achieved by comminution of ingesta with an enormous variety of teeth via chewing . Teeth are exposed to wear and hence in danger of losing functionality, and the actual causes of tooth wear remain under debate.