Amphibians

Question 1

What belongs to the class Anura?

Answer 1

Frogs and toads.

Question 2

What characteristics are common of the class Anura?

Answer 2

Long hind limbs, short/stiff bodies, hop movement.

Question 3

What belongs to the class Urodeles?

Answer 3

Salamanders and Newts.

Question 4

What characteristics are common of the class Urodeles?

Answer 4

Equal sized limbs, long/slender bodies, waddle movements.

Question 5

What belongs to the class Gymnophionans?

Answer 5

Caecilians.

Question 6

What characteristics are common of the class Gymnophionans?

Answer 6

No limbs, long/slender bodies, slither movement.

Question 7

What changes do we observe in amphibian metamorphosis?

Answer 7

Small mouth for algae feeding replaced with large mouth for catching prey, herbivorous gut changes to carnivorous gut, development of legs and lungs and degeneration of gills and tail.

Question 8

What happens in the first period of metamorphosis of terrestrial frogs?

Answer 8

Pre-metamorphosis; tadpoles increase in size, little change in shape.

Question 9

What happens in the second period of metamorphosis of terrestrial frogs?

Answer 9

Pro-metamorphosis; hind legs appear, growth slows down.

Question 10

What happens in the third period of metamorphosis of terrestrial frogs?

Answer 10

Meta-morphic climax; fore legs emerge and tail regresses.

Question 11

Why is the metamorphic climax stage so rapid?

Answer 11

Tadpoles are most vulnerable at this stage; not perfectly adapted to either environment as small legs no good for jumping and small tail can’t swim fast for escape from predation.

Question 12

What controls metamorphosis?

Answer 12

Controlled by hormones and associated receptors in response to environmental cues.

Question 13

What gland in particular is important in the metamorphosis process?

Answer 13

Thyroid.

Question 14

What common characteristics do amphibians share?

Answer 14

Smooth/moist skin, multiple methods of respiration, pedicellate teeth, green rods (vision), operculum (hearing), elevator bulbs muscle.

Question 15

What adaptions make the amphibian skin smooth and moist?

Answer 15

Absence of keratinised scales, /claws, presence of mucous glands, pelvic patch, permeable bladder

Question 16

How is the pelvic patch a method of controlling water loss?

Answer 16

Highly vascularised ventral skin absorbs majority of water.

Question 17

How is a permeable bladder a method of controlling water loss?

Answer 17

Stores dilute urine away from water.

Question 18

How is the amphibian skin adapted for defence?

Answer 18

Many poison glands on the dorsal surface.

Question 19

What multiple methods of respiration exist in amphibians?

Answer 19

Across moist skin, in buccal cavity/pharynx, in paired lungs, in gills (larval forms and neotenic).

Question 20

What aspects of the amphibian body plan restricts gas exchange?

Answer 20

Lungs too small, lack intercostal muscles between ribs so cannot expand to change air pressure, lack diaphragm.

Question 21

What solution fixes the restrictions on gas exchange?

Answer 21

Use a Buccal pump in the floor of the mouth and throat which pushes air into the lungs.

Question 22

How exactly does the Buccal pump work?

Answer 22

Air drawn into cavity with glottis closed, nares closed and glottis opened, floor of mouth raised and air forced into lungs.

Question 23

What term defines the Buccal pump kind of breathing?

Answer 23

Positive pressure breathing.

Question 24

What is unique about the Pedicellate teeth?

Answer 24

Crown and base of tooth separated by uncalcified dentine/fibrous tissue which allows for “flex” of tooth for prey handling (all carnivores).

Question 25

Why do amphibians possess green retinal cells?

Answer 25

Need to maximise absolute sensitivity, visual acuity and colour sensitivity.

Question 26

what does the elevator bulb muscle do?

Answer 26

Muscle beneath theses bulges outward and increase buccal cavity for breathing and swallowing.

Question 27

What aspects of the amphibian skeleton were important in the survival on land?

Answer 27

Have a pelvic girdle which attaches appendages to the vertebral column, providing support on land.

Question 28

What aspects of the circulatory system changed in the evolution of amphibians?

Answer 28

3 heart chambers, both atria empty into single ventricle, mixing of blood.

Question 29

What sensory adaptations do amphibians have?

Answer 29

3 sectioned brain, sensory receptors on skin, lateral line system similar to fish.

Question 30

How is the eyelid adapted to aid vision?

Answer 30

Lower eyelid is movable, it cleans and protects the eye (nicitating membrane).

Question 31

What features differ with Caecilians?

Answer 31

Eyes have regressed, chemosensory structure, dermal scales present, operculum absent, teeth are more curved, parental investment by skin feeding.

Question 32

What Is unique of Urodeles reproduction?

Answer 32

Well-defined courtship/mating behaviour, male spermatophore and internal fertilisation.

Question 33

What behaviour is exhibited by frogs when attracting a mate or when distressed?

Answer 33

Vocalisation.