lab 4- skull and teeth

Question 1

what is dermatocranium?

Answer 1

dermal bone that formed dermal armor in ancestral fish, in later groups the bone fuses with other components

Question 2

what is chondrichthyes?

Answer 2

shark

Question 3

did chondrichthyes lose its dermal bones?

Answer 3

yes

Question 4

what is the single cartilage in the upper and lower jaw of sharks?

Answer 4

upper jaw: palatoquadrate
lower jaw: Meckels cartilage

Question 5

what is hyostylic suspension in sharks?

Answer 5

-when the upper jaw is attached by a flexible ligament at the anterior, and a hyomandibula at the posterior, allowing for the jaw to drop and protrude as it opens

Question 6

what is osteichthyes?

Answer 6

bony fish

Question 7

how does the lower jaw articulate in bony fish?

Answer 7

it articulates between articular bone of the lower jaw and quadrate bone of the upper

Question 8

what are sutures on alligators?

Answer 8

connections between skull bones

Question 9

what are the new parts of bone that make up the jaw in mammals?

Answer 9

-dentary bone for lower jaw
-squamosal bone for cranium

Question 10

what did the articular and quadrate bone become into in mammals?

Answer 10

-bones in the ear:
-malleus
-incus
-stapes

Question 11

how many temporal fenestrae do anapsids have?

Answer 11

none

Question 12

how many temporal fenestrae do synapsids have?

Answer 12

one

Question 13

how many temporal fenestrae do diapsids have?

Answer 13

two

Question 14

what is the part of the tooth that is exposed?

Answer 14

crown

Question 15

what is the part of the tooth that is hidden?

Answer 15

root

Question 16

what is the tooth made of?

Answer 16

internal dentine and external enamel

Question 17

what bone covers the root of teeth?

Answer 17

cement bone

Question 18

what is homodont teeth uniformality?

Answer 18

teeth that are all the same

Question 19

what is heterodont teeth uniformality?

Answer 19

teeth that are different

Question 20

what is polyphyodont teeth replacement?

Answer 20

teeth are replaced repeatedly

Question 21

what is diphyodont teeth replacement?

Answer 21

only two generations of teeth, juvenile and adult

Question 22

what are the types of teeth?

Answer 22

-incisors, canines, premolars, and molars

Question 23

what are secodont cheek teeth?

Answer 23

teeth that are blade-like and used for slicing or chopping

Question 24

what are lophodont cheek teeth?

Answer 24

teeth that have ridges and run from cheek to tongue

Question 25

what are selenodont cheek teeth?

Answer 25

teeth that have a slightly curved ridge that run from front to back

Question 26

what are bunodont cheek teeth?

Answer 26

4 round cusp teeth

Question 27

what is the elongated gap between teeth called?

Answer 27

diastema

Question 28

what is the point of the temporal fenestrae?

Answer 28

allows for longer jaw muscle for more strength and more surface area

Question 29

describe the transition from jaw bones of sharks to salmon, alligators, then mammals?

Answer 29

shark: meckels cartilage and platoquadrate --> salmon: articular, quadrate --> alligator: articular, quadrate --> mammals: malleus, incus, and stapes

Question 30

did sharks have upper and lower teeth bearing bones?

Answer 30

no

Question 31

what are the teeth bearing bones in salmon, alligator and cougars?

Answer 31

maxilla, premaxilla and dentary

Question 32

between amphibians, sphenodon (tuatara), lizard, snake, turtle, crocodilian, bird, and mammals, which are anapsids, diapsids, and synapsids?

Answer 32

amphibians: anapsid sphenodon: diapsid lizard: diapsid snake: diapsid turtle: anapsid crocodilian: diapsid bird: diapsid mammal: synapsid

Question 33

between amphibians, sphenodon (tuatara), lizard, snake, turtle, crocodilian, bird, and mammals, which are homodont, heterodont, and edantate for teeth uniformality?

Answer 33

amphibians: homodont sphenodon: heterodont lizard: homodont snake: heterodont turtle: edentate crocodilian: homodont bird: edentate mammals: heterodont

Question 34

between amphibians, sphenodon (tuatara), lizard, snake, turtle, crocodilian, bird, and mammals, which are polyphyodont and diphyodont for teeth replacement?

Answer 34

amphibian: polyphyodont sphenodon: polyphyodot lizard: polyphyodont snake: polyphyodont turtle: N/A crocodilian: polyphyodont bird: N/A mammals diphyodont

Question 35

between opossum, carnivore, herbivore (grazer), herbivore (rodent), and an omnivore, which are secodont, lophodont, selenodont, bunodont, and unspecialized for cheek teeth?

Answer 35

opossum: unspecialized carnivore: secodonts herbivore grazer: selenodonts and lophodont on horses herbivore rodent: lophodont omnivore: bunodont

Question 36

why are opossum unspecialized in cheek teeth?

Answer 36

because they have ancestral teeth which later evolve into others in mammals, they also were omnivores so didn't have to specialize into anything

Question 37

why are carnivores secodonts in cheek teeth?

Answer 37

-because they eat meat, hence needing sharp teeth to cut -have sharp incisors, molars, carnassial teeth, large canines, less wear on molars -back teeth meet first then front for shearing

Question 38

why are herbivore grazers selenodonts or lophodonts in horses?

Answer 38

-because they eat grass, twigs, and leaves which have low energy hence needing to eat for more time -teeth meet at the same time for efficient chewing at an angle -no canines, lack upper incisors, self sharpening teeth -have a diastema for more visibility when grazing and for more food storage in mouth -two pairs of enamel

Question 39

why are herbivore rodents lophodonts?

Answer 39

-eat seeds, nuts, and wood -chew front to back -have diastema, have upper incisors, no canine, worn through enamel -extra iron on incisors

Question 40

why are omnivores bunodonts? what do bears, pigs, and racoons have?

Answer 40

-eat plant, berries and meat, but not adapted for large prey -wider cheek teeth, mix of cusps and pits, good for pulping and mashing -no diastema on bears and pigs -pigs have sharper incisors -racoons have wider cheek teeth

Question 41

which temporal fenestrae is ancestral?

Answer 41

anapsid

Question 42

is edentate in turtles and birds homoplasious? what is the benefit of it?

Answer 42

-yes -less weight for birds allowing for better flight, and less energy use for slow metabolism of turtles, making it more energy efficient

Question 43

why are humans heterodonts and diphyodonts?

Answer 43

-humans are heterodonts because we have a diverse diet and need different types of teeth for different foods -humans are diphyodonts because we need good teeth alignment to chew more efficiently