AMPHIBIANS
Class: Amphibia
Chapter 30.3 & 30.4
Characteristics
 Legs
& Lungs
 Double-loop circulation
 Partially divided heart
 Cutaneous respiration
 Reproduce in a wet area
Movement & Response
 Support
from a strong internal skeleton
 Primary sensory organs = eyes & ears
 Tympanic membrane: eardrum,
transmits sound to the inner ear
Respiration
 Most
adult amphibians breathe with lungs
1. Lungs = baglike organ that allows for
oxygen & carbon dioxide to be exchanged
2. Gills
3. CUTANEOUS (through their thin, moist
skin) respiration  diffusion
Circulation
 Partially
divided heart: Left & right sides
by a septum
 Bottom isn’t divided  mixture of
oxygen-rich & poor blood is given to
the body tissues
 3-chambered heart
 “Double-loop” circulation is an
advantage over the “single-loop” of fish
= FASTER blood flow to the body!
Three main groups:
salamanders, caecilians, &
frogs and toads
Salamanders
 Elongated
bodies, long tails, smooth &
moist skin
 400 species
 Can’t stay away from water for long 
skin must stay moist
 Lay eggs in water, fertilization = internal
 A few species keep their gills when they
become adults
Caecilians
 Burrowing
amphibians with small, bony
scales embedded in their skin
 Legless & wormlike
 Blind
 Sexual reproduction, lay eggs or live
young
Frogs and Toads
 4,000
species
 Carnivores & use their long, stick tongue
to get food
 Body is adapted for jumping
 Toads = squat bodies & shorter legs,
bumps on the body
Reproduction = Metamorphosis
• Need water to complete their life cycle
• Eggs fertilized externally
What’s killing them off?