Lissamphibia

Question 1

Why is fossil for lissamphibia poor?

Answer 1

Specimens are small and easily destroyed.

Question 2

Amphibians display either herbivory or omnivory. True or false?

Answer 2

False - all amphibians are carnivorous.

Question 3

Give 2 major defining characteristics of lissamphibia.

Answer 3

1. Biscupsid pedicellate teeth

2. Permeable skin

Question 4

Define bicuspid pedicellate teeth.

Answer 4

2-pronged teeth with a flexible fibrous region.

Question 5

Why do amphibians have permeable skin?

Answer 5

Because they cutaneous respiration.

Question 6

Amphibians only respire cutaneously. True or false?

Answer 6

False - the have lungs also for pulmonary respiration.

Question 7

Give the 3 groups of amphibian.

Answer 7

1. Anura
2. Urodela
3. Gymnophiona

Question 8

The anura are the largest group of up to 1000 species. Which animals do they contain?

Answer 8

The frogs.

Question 9

How many trunk vertebrae do anurans have?

Answer 9

Between 5-9.

Question 10

Give 4 major examples of how anurans are adapted for a jumping lifestyle.

Answer 10

1. Large, open head = lightweight
2. Short trunk - stability
3. Urostyle and modified pelvis = stability
4. Long legs

Question 11

Define the urostyle.

Answer 11

A long bone at the end of the spine were the vertebrae have used together.

Question 12

The larvae undergo complete metamorphosis into adults. True or false?

Answer 12

True.

Question 13

Triadobatrachus was a primitive frog from what period?

Answer 13

The Triassic.

Question 14

How many trunk vertebrae does Triadobatrachus have? We are beginning to see a reduction from the ancestral condition.

Answer 14

14.

Question 15

In what period did the earliest ‘true frogs’ appear?

Answer 15

The Jurassic.

Question 16

There is much diversity within the anurans. How does the Mexican burrowing toad prevent drying out?

Answer 16

It lives underground and is nocturnal.

Question 17

There is much diversity within the anurans. The midwife toad demonstrates what kind of care for its young?

Answer 17

Paternal, the male carries the eggs on his back.

Question 18

There is much diversity within the anurans. Poison dart frogs secrete toxins in their skin. What kind of lifestyle do they have?

Answer 18

Diurnal and arboreal.

Question 19

There is much diversity within the anurans. Which species of frog does this:

The male and female clasp together in mating and secrete their gametes. The male beats a mucous secretion with his legs until it becomes foam, which is hardened on the outside but moist on the inside. The fertilised eggs are stored in this ball and hung from a branch. When the froglets eventually hatch out they fall into a pool of water below.

Answer 19

Wallace’s tree frog.

Question 20

Within the anura, all fertilisation is external. True or false?

Answer 20

True.

Question 21

The urodela contains which animals?

Answer 21

Salamanders and newts.

Question 22

What is another name for the urodela?

Answer 22

The caudata.

Question 23

When did the earliest urodeles appear?

Answer 23

The Jurassic.

Question 24

Describe the characteristic body plan of a urodele.

Answer 24

1. Large, open framework head
2. Elongate shape, more presacral (trunk) vertebrae than anurans
3. Long tail
4. Reduced limbs

Question 25

In what kind of motion do urodeles move?

Answer 25

A lateral undulation, wiggle side to side.

Question 26

Within the urodeles, all fertilisation is external. True or false?

Answer 26

False - all fertilisation is internal.

Question 27

Urodeles often display elaborate courtship rituals. True or false?

Answer 27

True.

Question 28

Approximately how many species of salamanders and newts are there?

Answer 28

500-600.

Question 29

Urodeles can be either fully a) aquatic, b) semi-aquatic or c) highly terrestrial. Briefly state how their bodies are differently adapted.

Answer 29

a) Often have external gills
b) Traditional bodyplan
c) Have limbs that are better developed than in other urodele species.

Question 30

What animals does the gymnophiona contain?

Answer 30

Caecilians.

Question 31

What is another name for the caecilians?

Answer 31

The apodans.

Question 32

How many species of caecilian are there?

Answer 32

100-200.

Question 33

Gymnophionans are the only group of amphibians that are restricted in their global distribution. True or false?

Answer 33

True - the gymnophiona can only survive in tropical regions whereas the anura and urodela are often found in temperate regions.

Question 34

Caecilians are very good swimmers and have invaded aquatic niches. However most caecilian species have what kind of lifestyle?

Answer 34

Fossorial, a burrowing lifestyle.

Question 35

How are caecilians adapted for burrowing?

Answer 35

They have a solid and bullet-shaped head, as opposed to the large, open framework head of other amphibians.

Question 36

The eyes of caecilians are redundant and thus reduced or covered by dermal bone. What do they have instead?

Answer 36

A sensory tentacle at the end of the snout.

Question 37

Caecilians have reduced limbs. True or false?

Answer 37

False - they are completely limbless.

Question 38

Caecilians have internal fertilisation like urodeles. True or false?

Answer 38

True.

Question 39

There are 2 major theories for the evolution of lissamphibia. What are they?

Answer 39

1) They evolved from temnospondyls

2) They evolved from lepspondyls

Question 40

Explain support for the theory that lissamphibia evolved from temnospondyls. Give the 2 main arguments.

Answer 40

1. Dissorophids had large, open framework skulls, reduced trunk vertebrae and impedance-matching ears like modern frogs.
2. Dissorophoids also had bicuspid pedicellate teeth like other lissamphibia.

Question 41

Explain support for the theory that lissamphibia evolved from lepospondyls.

Answer 41

1. Caecilians and microsaurs both have bullet-shaped skulls, bone posterior to the jaw joint and palatal teeth.

Question 42

Explain why there is doubt that the lissamphibia evolved from the lepospondyls.

Answer 42

It is thought the similarities between microsaurs and caecilians arose by convergent evolution, as during development caecilians possess open framework in their skulls characteristic of other lissamphibians.