Question

Explain the term thecodont and diphyodont.

Answer 1

Hint: Both terms - thecodont and diphyodont, are both related to the pattern and arrangement of the teeth in mammals. They help us to get detailed knowledge of teeth in the socket and gums.

Complete step by step answer:
Thecodont is used to denote a morphological arrangement in which the base of the tooth is completely enclosed in a deep socket of bone. This type of arrangement is seen in crocodilians, dinosaurs, and mammals.
A diphyodont is seen in many animals that have two sets of teeth in their lifetime i.e first set is temporary and falls after a while. The second set of teeth replace the first set and are permanent now.

Additional information:
Two more types of morphological arrangements are seen in different animals. They are as follows:
Acrodont teeth are fused to the edge of the mandibles and the maxillae. 
Pleurodont teeth are attached to the medial surface of the mandibles and maxillae. It is often seen that as pleurodont teeth will regenerate if lost or broken, but acrodont teeth will not regenerate.
In humans, teeth morphology is explained as diphyodont, thecodont, and heterodont.
Heterodont means a condition in which there are different types of teeth present.
For example, in humans four different types of teeth are present. Which are incisors, canine, premolars, and molars. Humans have a total of 32 teeth present in them.
- Incisors: Human incisors are eight in number. These are the first set of teeth we have at the age between six and eight years old. These types of teeth are used for biting food particles.
- Canines: Our canines are the next teeth that develop in your mouth. Humans have four canines and they are the sharpest teeth, used for tearing apart food.
- Premolars -  Premolars are used for crushing and tearing of food. Humans have eight premolars in total.
- Molars:   Molars are human's largest teeth. Their function is to grind, tear, and crush food. They are eight in number.
- Wisdom teeth: They are erupted later in life, somewhat at age of 12 or 13.It can arise later also. They are four in number.

Note: A dental formula is used to express the number and types of teeth present in any organism. It is written as an expression of the number of each type of tooth on one side of the upper jaw over the number of teeth on one side of the lower jaw. The dental formula of a human adult is 2123/2123.