Mammal Feeding & Locomotion

Question 1

What is diphyodonty?

Answer 1

Full replacement of one set of teeth with another set once in life

Question 2

Why do mammals have a unique fleshy seal against the hard palate ?

Answer 2

Isolates breathing and swallowing. Prevents liquid from entering pharynx

Question 3

What are the advantages of lactation?

Answer 3

Allows offspring production to be separated from seasonal food supply, mammals can store food as fat and covert it later, not dependant on bi-parental care.

Question 4

What is common of mammalian jaws?

Answer 4

Have molars, can masticate, jaws moved in rotary fashion, narrow-set lower jaws allow sideways movement.

Question 5

What are the four types of mammalian teeth?

Answer 5

Incisors; seize food, canines; stab prey, premolars; slice food, molars; break food into fine pieces.

Question 6

Why have artiodactyla (cattle etc) evolved 4-chambered stomachs?

Answer 6

Cellulases are not produced so the three pre-stomach chambers house symbiotic micro-organisms that aid digestion.

Question 7

In what order does the ruminant digestive work?

Answer 7

Esophagus, food mixed with cellulose fermenting microorganisms in the rumen, Reticulum passes this mixture back to the mouth where it is reprocessed, passes to the omasum where is is concentrated by water reabsorption, enters abomasum (true stomach) which secretes HCl and proteases, kills microorganisms, food is digested then passed onto the small intestine for further digestion/absorption.

Question 8

What is responsible for 70% of ruminant’s nutrition?

Answer 8

Volatile fatty acids produced as bacterial waste products.

Question 9

Why do so many animals eat their poo?

Answer 9

Eat the faeces of their mother to obtain the gut bacteria required to properly digest cellulose.

Question 10

What forms of locomotion are there?

Answer 10

Saltatorial, cursorial, scansorial, gliding, swimming, powered flight.

Question 11

What features are common of mammals that exhibit saltatorial locomotion?

Answer 11

Large hind limb muscles, long hind limbs, forelimb very generalised, stiffening of spine, counter-balancing tail, ligament shock absorbers, fusion of cervical vertebrae.

Question 12

What are the advantages of saltatorial locomotion?

Answer 12

Extremely rapid acceleration and rapid changes in direction.

Question 13

What is Saltatorial movement?

Answer 13

Bipedal hopping usually seen in prey species e.g. Kangaroos.

Question 14

What is cursorial movement?

Answer 14

Running

Question 15

What are the two ways cursorial increase speed?

Answer 15

Stride rate or stride length.

Question 16

How do cursorials increase stride length?

Answer 16

Elongated distal limb bones, change in foot posture to reduce contact with ground, clavicle reduction allowing scapula to pivot and rotate as part of limb, increased torso-ventral flexion of the spine.

Question 17

How do curorials increase stride rate?

Answer 17

Increase number of joints, decrease inertia of limb distally, concentration of muscles to proximal locations.

Question 18

What is scansorial locomotion?

Answer 18

Climbing

Question 19

What are common features of climbers?

Answer 19

Friction pads, claws, prehensile tail and opposable digits, suction cups, stiffened trunks for vertical support, elongated forelimbs.

Question 20

What features are common of gliders?

Answer 20

Skin webbing between front and hind limb, reduced drag, tail rudder/balance for gliding precisely.

Question 21

How are mammals adapted to swimming?

Answer 21

Front limbs modified into propulsive flippers, fused cervical vertebrae, flukes.

Question 22

How are mammals adapted for digging?

Answer 22

Short forearms for power, use of incisors to dislodge soil, retain all 5 digits tipped with claws for breaking up soil.