1. WARM UP
Sketch the fin of a ray-finned bony fish and the fin of a lobe-finned bony fish.
Using your sketches, explain why lobe-finned fish were able to develop limbs.

2. Amphibians Notes
Phylum Chordata

3. General Characteristics
Respiration by lungs, skin, and gills
Three-chambered heart
Smooth and moist skin
Usually four limbs
Toes, but no claws
Ectothermic
Cold-blooded

4. Salamanders Resemble the simplest, earliest amphibians
Bend side to side when they walk

5. Frogs and Toads Best adapted amphibians (for life on land)
Long, powerful hind legs
Sticky tongue
Many skin glands
Some have defensive chemicals

6. Caecilians An amphibian snake Burrow through soil Lack legs
Eat insects and worms

7. WRAP UP
Why are amphibians more common in the southeastern United States than the southwest?
Why are amphibians most common in the Amazon rainforest?