T30 - Amphibians

Question 1

Briefly descript ichthyostega. What body plan features do they have?

Answer 1

early amphibians (semi-terrestrial tetrapod)

with features such as
- weight-bearing knee and ankle joints
- tail for balance

Question 2

What are the three extant amphibian types?

Answer 2

frogs, salamanders, and caecilians

Question 3

Expliain these characteristics of amphibians:
1. “naked” skin
2. ectothermic
3. water-dependent reproduction
4. weak eggs

Answer 3

1. skin is thin, moist, and water-gas permeable (used for secondary respiratory gas exchange). it is vulnerable to dessication and salt. it has mucous glands
2. relies on environmental heat sources to maintain body temperature via stable warm environments of behavioural thermoregulation
3. they are oviparous with external fertilization
4. their eggs lack protective shells and extraembryonic membranes

Question 4

Other than …
skin, water-reproduction, ectothermic regulation, and weak eggs
…what are the 4 other characteristics of amphibians?

Answer 4

1. buccal pump for lung ventilation
2. 3-chambered hearts
3. gills only in larval stages
4. external eardrums

Question 5

What does it mean when amphibians have “both ways of life”?

Answer 5

aquatic larvae and terrestrial adults

Question 6

What is the distinguishing characteristic of salamanders?

Answer 6

they have tails in both their larvae and adult forms

Question 7

Answer these questions about salamanders:
1. How do you distinguish adult salamanders from larvae?
2. How do salamanders move?
3. what do larvae and adult salamanders eat?

Answer 7

1. larvae have external gills, adults do not
2. they prefer to walk rather than jump
3. BOTH larvae and adults eat invertebrates

Question 8

What are the two characteristics of toads? Are they the same as frogs?

Answer 8

1. leathery skin
2. poison glands

they are a SUBSET of frogs

Question 9

Answer the following questions about frogs:
1. How can you distinguish larvae and adults?
2. what body characteristic of amphibians is exceptionally developed in frogs?
3. Do they exhibit parental care?

Answer 9

1. two ways:
   visually: adults lose their tails
   food: larvae eat algae, adults eat invertebrates
2. the ears
3. only SOME species

Question 10

What are the three defining characteristics of caecilians? (hint: habitat, body plan, fertilization)

Answer 10

1. legless amphibians
2. viviparous (internal fertilization)
3. burrowers

Question 11

What causes the global amphibian decline? Why is this a problem?

Answer 11

Cause: habitat destruction

Problem: threat to global biodiversity, amphibians are indicators of ecosystem stress