What is a tooth?
A: A tooth is a hard, calcified structure found in the jaws (or mouths) of
many vertebrates and used to break down
food.
The roots of teeth are covered by what?
A: Gums.
Teeth are not made of bone, but rather of multiple
tissues of varying density and hardness that originate from where?
A: The embryonic germ layer, the ectoderm.
he general structure of teeth is similar across the
vertebrates, although there is considerable variation in their what?
A: Form and position.
The teeth of mammals have deep what?
A: Roots.
This pattern is also found in some fish, and in what?
A: Crocodilians.
In most teleost fish, however, the teeth are attached
to what?
A: To the outer surface of the bone.
In lizards they are attached to what?
A: The inner surface of the jaw by one side.
In cartilaginous fish, such as sharks, how are the
teeth attached?
A: By tough ligaments to the hoops of cartilage that form the jaw.
Monophyodonts are animals that develop only one what?
A: Set of teeth.
Diphyodonts have an early set of deciduous teeth and a
later set of what?
A: Permanent or "adult" teeth.
Polyphyodonts develop many sets like Sharks who grow a
new set of teeth how often?
A: Every two weeks to replace worn teeth.
Rodent incisors grow and wear away continually through
what?
A: Gnawing, which helps maintain relatively constant length.
In many reptiles and fish, teeth are attached to what?
A: The palate or to the floor of the mouth.
Some teleosts even have teeth in what?
A: The pharynx.
Teeth appear to have first evolved in what animals?
A: Sharks.
The shape of the animal's teeth are related to its
what?
A: Diet.
In dogs, the teeth are less likely than humans to form
dental cavities because of what?
A: The very high pH of dog saliva, which prevents enamel from demineralizing.
An adult horse has how many teeth?
A: Between 36 and 44.
Horse teeth can be used to estimate the animal's what?
A: Age.
Elephants' tusks are specialized incisors for doing
what?
A: Digging food up and fighting.
