Amphibians were the first vertebrates to live on land but still require water to reproduce. They developed lungs, legs, and moist permeable skin to survive out of water. Amphibians include frogs, toads, salamanders and caecilians. Many amphibian populations are declining due to threats like climate change, habitat loss, pollution and disease.

1. Objective: Phylum Chordata: Amphibians Homework: CC 25.2-25.4

2. Animals that live on land are faced with different environmental challenges than those that live in the water Adaptations for life on land: Tetrapods – “four-footed”; two sets of paired appendages that are modified as legs that can support the animal Lungs to avoid dessication (drying out)‏ The Transition from Water to Land

3. What are Lungs? Gas exchange (inhaling oxygen and exhaling carbon dioxide) requires a moist environment But air is a dry environment, so lungs are folded inside the animal's body To limit the loss of water, lungs open to the outside by narrow passages.

5. Amphibians were the first vertebrates to live on land Amphibians live part of their life cycle in water and part on land Do NOT make amniotic eggs Larval stage – in water METAMORPHOSIS Adult – on land As larvae, use gills to breathe As adults, most use lungs, however, skin may stay moist and also serves in gas exchange

9. Amphibians include frogs, toads, caecilians, and salamanders/newts

10. The Difference Between Frogs and Toads Frogs – smooth, moist skin; stick to mostly aquatic environments Toad – rough skin and live in terrestrial environments