Lecture 7

Question 0

Why were plants a good source of energy 365mya?

Answer 0

They were abundant, an unexploited energy source with no competition

Question 1

What was the food chain for early tetrapods based upon?

Answer 1

The aquatic system of carnivory

Question 2

What challenge faced animals who wanted to use plants as an energy source?

Answer 2

Cellulose

Question 3

Why couldn’t early terrestrial animals digest cellulose?

Answer 3

It is composed of beta glucose which they were unable to digest.

Question 4

How did the synapsids jaw make it difficult for them to break down plant matter?

Answer 4

Sharp cone teeth which lacked dental occlusion
Jaw composed of several bones
Temporal fenestra was in line with lower jaw

Question 5

When did the synapsids walk the earth?

Answer 5

300mya

Question 6

How did the early cynodonts adapt to breakdown plant matter?

Answer 6

They acquired dental occlusion by changing the shape of their teeth
Their temporal fenestra was raised to increase jaw strength

Question 7

When did the early cynodonts roam the earth?

Answer 7

260mya

Question 8

How did the late cynodont adapt to mechanically breakdown plant matter?

Answer 8

Jaw articulation by two bones
Complex cusp pattern of molars and premolars
Temporal fenestra located above mode of action

Question 9

When did the late cynodonts roam the earth?

Answer 9

195mya

Question 10

What are the role of incisors?

Answer 10

Pincers for grasping or grooming

Elongated chisels for gnawing

Question 11

What is the function of canines?

Answer 11

Elongated to stab and hold prey

Question 12

What is the function of molars in carnivores?

Answer 12

Carnissal teeth

Slicing and tearing flesh

Question 13

What is the function of the molars in the herbivores?

Answer 13

Grinding

Question 14

What are the selenodonts?

Answer 14

Molars with crescent shaped ridges

Question 15

What are the lophodonts

Answer 15

Molars with ridges between cusps

Question 16

What are the loxodonts?

Answer 16

Molars with extreme lophodont ridges

Question 17

What are the four points on a molar?

Answer 17

Metacone
Hypocone
Paracone
Protocone

Question 18

What type of teeth are common in browsers?

Answer 18

Brachydont teeth which have low crowns and finite growth

Question 19

What time of teeth are common in grazers?

Answer 19

Hysodont which are high crowned teeth which are constantly growing

Question 20

How have insects adapted to breakdown cellulose?

Answer 20

They have developed endosymbiont relationships with bacteria that can break down cellulose by consuming them.

Question 21

How have tetrapods evolved to digest cellulose?

Answer 21

They have developed an endosymbiotic relationship by consuming the required microorganisms or consuming insects containg the required microorganisms

Question 22

Describe hindgut fermentation

Answer 22

The caecum has been enlarged ti allow faster digestion
Fermentation of cellulose by microorganisms
Cellulose utilisation is 45%
Suits high starch food
Suits low energy food

Question 23

Describe foregut ruminants

Answer 23

Enlargement of foregut and additional mechanical breakdown
Cheing the cud
Longer digestion 
60% cellulose abosrbed
Inefficient processing of starch

Question 24

What is chewing the cud?

Answer 24

When contents are rechewed to further breakdown cellulose

Question 25

Which method of fermentation do small mammals prefer?

Answer 25

Hindgut fermentation as need energy fast

Question 26

What type of digestion do medium sized mammals prefer?

Answer 26

Foregut rumination

Question 27

What type of digestion do very large mammals prefer?

Answer 27

Hundgut fermenters