Lecture 18- Amphibians

Question 1

What was Amphibians the first do to?

Answer 1

First vertebrae group to move to terrestrial environment

Question 2

List 4 problems associated with amphibians life on land

Answer 2

1. Desiccation/Lack of Water- adults and embryos
2. Oxygen pressure- hard to get O2 from air and moisture required to dissolve to
3. Gravity/Lack of buoyancy- limbs and blood pressure
4. Temperature/Lack of consistency- thermoregulation

Question 3

Why did amphibians move to land- 3 reasons

Answer 3

• variety of habitats
• no predators
• shelter for young

Question 4

What pre-adaptations did the Devonian fishes have for transitioning to life on land ( 5 )

Answer 4

• Lungs: pharyngeal out pocketings
• Double circulation system
• Muscular and bony fins
• Pelvic and pectoral girdles
• well developed kidneys

Question 5

What are the 3 orders of Amphibia

Answer 5

1. Anura (frogs and toads)
2. Caudata (salamanders and newts)
3. Apoda (caecilians)

Question 6

List 7 characteristics of Amphibians

Answer 6

• Tetrapods w bony skeleton
• Limbs & Lung reduced or absent
• Cutaneous respiration
• Pulmonary veins
• 3 chambered heart
• moist glandular skin
• ectothermic

Question 7

List 4 characteristics for Apoda

Answer 7

• Many species in tropical forests
• No limbs (borrowers)
• many blind as adults
• carnivorous

Question 8

List 4 characteristics for salamanders and newts

Answer 8

• most in temperate regions
• tail ( 4 limbs)
• carnivorous
• aquatic or terrestrial

Question 9

List characteristics for Anura

Answer 9

• worldwide distribution
• 4 limbs (modified for jumping)
• respiration- skin mouth, lungs
• no tail in adult
• tadpole (herbivorous), adult (carnivorous)

Question 10

What are the possible causes of a decline in Amphibians (3)

Answer 10

• higher temps = water loss
• habitat loss and fragmentation
• enigmatic disease- chytrid fungus

Question 11

Reproduction in Apoda (2)

Answer 11

• internal fertilisation = female parental care
• male has copulatory organ

Question 12

Reproduction in Caudata (4)

Answer 12

• internal fertilisation = female parental care
• male has no copulatroy organ
• adults an larvae can be terrestrial or aquatic
• paedomorphosis

Question 13

Reproduction in Anura

Answer 13

• External fertilisation = male parental care
• males have advertisement calls
• amplexus breeding
• eggs usually in water
• tadpole metamorphose