CTB 4 – Evolution functional adaptions of jaws and dental tissues

Question 1

Where is the dental lamina derived from?

Answer 1

Ectodermal epithelium

Question 2

What is a homodont? Animal example.

Answer 2

Same teeth within the dentition

Crocodiles

Question 3

What is a hetrodont? Animal example.

Answer 3

Different teeth within the dentition

Most mammals - human

Question 4

What is a polyphydont? Animal example.

Answer 4

Teeth continually replaced when animals grow

Fish, amphibians and reptiles

Question 5

What is a diphydont? Animal example.

Answer 5

2 generation of teeth
Human have primary and permament
Vertical replacement in humans

Question 6

When teeth are replaced in elephants what orientation do they erupt?

Answer 6

They are replaced horizontally

Question 7

What is the tooth attachment of teeth to the jaw (3 types)? Animal examples.

Answer 7

• Acrodonty, to tip of jaw, bony fish
• Pleurodonty, to side of jaw, reptiles
• Thecodonty, embedded in sockets, human and dinosaurs

Question 8

What is the tooth connection of teeth to the jaw (3 types)?

Answer 8

• Ankylosis – via bone only
• Gomphosis – by unmineralized fibres if tooth in socket – human
• Aulacodonty – by unmineralized fibres if tooth no set-in socket

Question 9

What is brachyodont? Animal example.

Answer 9

Low crowned teeth

Human

Question 10

What is hypsodont? What is the reason for these teeth?

Answer 10

High crowned teeth

When enamel surface is lost the gum line lowers to compensate this as their teeth are being ground down

Question 11

What is the function of a tooth comb in some animals?

Answer 11

For grooming and brushing their fur

Question 12

What are the carnassial teeth and what is their function?

Answer 12

• Upper premolar (P4) and 1st lower molar (M1)

- Shearing and slicing meat

Question 13

What TMJ movement do carnivores have?

Answer 13

Vertical movement – scissoring movement

Question 14

What TMJ movement do herbivores have?

Answer 14

Horizontal movement

Question 15

What is the difference in the levels of the TMJ and teeth in carnivores and herbivores?

Answer 15

Carnivores - TMJ and teeth are at the same level

Herbivores - TMJ above tooth rows

Question 16

What are the muscles of mastication that allow for vertical and horizontal movement?

Answer 16

Vertical - Temporalis

Horizontal - Masseter

Question 17

What is special in herbivores incisors?

Answer 17

There is a gap behind incisors called a diastema

Question 18

What is special about granivores incisors? Animal example.

Answer 18

Every growing incisors

Such as rodents

Question 19

What is the function of large incisors in carnivores?

Answer 19

For grabbing

Question 20

What animal types have a horny pad?

Answer 20

Grazers and browsers

Question 21

How many rows of teeth do rodents have?

Answer 21

2

Question 22

What is the evolutionary trend in the number of teeth? Animal examples.

Answer 22

Become fewer and fewer

• Fish – 1000’s teeth
• Amphibians less
• Mammals even less

Question 23

Where is the placement of teeth in fish?

Answer 23

Oral cavity and pharynx

Question 24

What is the dental formula for human teeth?

Answer 24

3/3 I, 1/1 C, 4/4 P, 3/3 M

Question 25

When does tooth growth in humans stop?

Answer 25

At sexual maturity