Lecture 17- Amphibians

Question 1

The study of amphibians and retiles is referred to as ____.

Answer 1

Herpetology

Question 2

What does the open terrestrial niche hypothesis state?

Answer 2

The evolution of amphibians due to less competition on land and more resources on land

Question 3

Amphibian characteristics?

Answer 3

• Tetrapod
• Body forms vary among species
• Skin smooth, moist, and glandular
• Lungs and cutaneous respiration; some reversals to gills
• Ectothermic: regulation of body temperature dependent on external surfaces
• Tympanic membranes (posterior to eyes, used to syphon sound; hearing) and Stapes
• Paired nostrils (olfaction (smell) and chemoreception (picking up chemical compounds; ex: pheromones))
• External fertilization (frogs go through complete metamorphosis)
• 3 chambered heart

Question 4

List the process of the amphibian heart.

Answer 4

deoxygenated blood enters vena cava -> right atrium -> enters sinus venosus -> singular muscular ventricle -> pumped out through pulmocutaneous artery -> blood gets to lung and picks up oxygen -> returns through pulmonary vein -> enters left atrium -> goes back to ventricle -> conus arteriosis -> blood enters aorta

Question 5

The two major circuits in double circulation are the ___ circuit, where blood is oxygenated, and the ___ circuit, where oxygenated blood is passed from the heart to the rest of the body.

Answer 5

Pulmonary circuit; Systematic circuit

Question 6

Order: Caudata

Answer 6

• Salamanders and Newts
• 655 species (greatest diversity in North and Central America)
• Early salamanders (aquatic lifestyles); More derived salamanders (terrestrial lifestyle)

Question 7

What are the respiratory reversals in salamanders?

Answer 7

external gills complete respiration (Axolotl species)

Question 8

What are some traits of the lungless salamanders?

Answer 8

• Family -> Plethodontidae
• Most diverse salamander family; widest geographical distribution
• Cutaneous respiration
• No lungs; space is used to hold coiled tongue in chest cavity
• Nasolabial grooves: enhances chemoreception

Question 9

Salamanders utilize ____, showing predators that they are toxic with their bright, warning coloration, also known as ____ coloration.

Answer 9

Unkenreflex; Aposematic coloration