Amphibians

Question 1

Environment

Answer 1

Freshwater/moist land habitats
* Thin skin is easily desicated
* Eggs shed into water or moist environment

Question 2

External gills

Answer 2

• Gills exposed to the environment
• Develop from pharyngeal slits
• Found in all amphibian larvae

Question 3

Respiration

Answer 3

• Cutaneous (all amphibians)
• Buccal
• Gills and/or lungs

Question 4

Reproduction

Answer 4

Sexual Reproduction
* Dioecious
* Predominantly oviparous
* Eggs are aquatic
* Indirect development
* Internal fertilization (except in frogs)
* Paedomorphosis in salamanders

Question 5

Taxonomy

Answer 5

• Order Gymnophiona – Caecilians
• Order Urodela –Salamanders
• Order Anura - Frogs

Question 6

Order Gymnophiona – Caecilians
* Form:
* Environment:

Answer 6

• Elongated, limbless, burrowing animals
• Found in tropical climates
• Eyes small (can be covered by skin)

Question 7

Order Urodela - Salamanders
* Form:
* Environment:

Answer 7

• Tailed amphibians
• Abundant & diverse in North America
• Most have limbs at 90° to trunk

Question 8

Life Cycle of salamanders

Order Urodela - Salamanders

Answer 8

Aquatic larvae that metamorphose into terrestrial adults

Question 9

Paedomorphosis

Answer 9

Evolution of an adult form that resembles an ancestral juvenile
* Reach maturity while retaining their gills, aquatic lifestyle, and other larval characteristics

Question 10

Unusual lifecycle: Aquatic salamanders

Order Urodela - Salamanders

Answer 10

Common mudpuppy:
* Entire life cycle is aquatic
* Internal fertilization
* Lay eggs in the water
* Aquatic larvae w/ external gills
* Adults retain extern gills
* Also have weak lungs

Amphiumas:
* Entire life cycle is aquatic
* Larval form w/ gills
* Loses gills before adulthood
* Breath through lungs
* Vestigial legs

Question 11

Order Urodela - Salamanders

Unusual lifecycle: Terrestrial salamanders

Answer 11

Pygmy salamander
* Entire life cycle is terrestrial
* Internal fertilizaiton
* Lay eggs in soft, moist earth
* Direct development
* Lungless - cutaneous respiration

Question 12

Order Urodela - Salamanders

Unusual lifecycle: Double metamorphosis

Answer 12

Red-spotted newt
* Aquatic gilled larvae
* Terrestrial juvenile (lungs)
* Aquatic adult (lungs)

Question 13

Order Anura - Frogs
* Form:
* Environment:
* Reproduction:
* Development:

Answer 13

• Without tail and specialized for jumping
• Most often indirect development
• External fertilization
• Paedomorphosis does not occur

Question 14

Order Anura - Frogs

Life cycle

Frogs

Answer 14

• Males attract females
• Amplexus
• External fertilization
• Egg absorbs water and swells
• Eggs layed in huge masses
• Embryos develop into tadpole
• Tadpoles hatch
• External gills develop
• Hind limbs develope then forelimbs
• Tail is absorbed
• Internal changes (lungs develop, gills absorbed, intestine becomes shorter, mouth is transformed)
• Metamorphosis

Question 15

Order Anura - Frogs

Feeding
Tadpoles ?
Adults?

Answer 15

• Tadpoles are herbivores (contain keratinzed jaws for scraping vegetation)
• Adults are carnivores