2. Amphibians Kingdom Animalia

3. Evolution O Approximately 345 million years ago. O Evolved from lobe-finned fish.

4. Adaptation to Life on Land O Legs in place of fins. O Stronger bones & muscles. O Lungs in place of gills. O Keratinized skin to prevent drying out. Click on the diagram above to watch a video on frog adaptations…

5. Amphibians are... O Cold-blooded. O Torpor O Torpor - state of dormancy. O Hibernation (winter)/ Estivation(summer)

6. Classification O Order Anura O Order Anura - Without tails (Ex. Frogs & toads) O Order Urodela O Order Urodela - Visible tails (Ex. Salamanders) O Order Apoda O Order Apoda - Without legs, wormlike (Ex. Caecilians) O Order Trachystoma O Order Trachystoma - Minute forelimbs & no hind limbs (Ex. Mud eels & sirens)

7. Amphibian Reproduction O Two life stages: O Aquatic tadpole stage. O Partially terrestrial adult stage. once O Breed once a year. O External fertilization. O Eggs hatch within 12 days of fertilization. O Amplexus

8. Metamorphosis O Change from an aquatic larva to adult. O Legs grow & tail disappears. O Mouth broadens - developing teeth & jaws. O Saclike bladder in throat divides to form lungs. O Heart develops a third chamber. O Ability to regenerate disappears. O Thyroxine O Thyroxine - Hormone; stimulates metamorphosis

9. Frog Dissection