Phylum Amphibia

1. Phylum Amphibia (American bullfrog – Rana catesbiana)

2. Froggy Classification Phylum – Chordata Sub-phylum – Vertebrata Class – Amphibia Super-order – Anura (meaning “without tail”) Order – Salientia (includes frogs and toads) Family – Ronidae Genus – Rana Species - catesbiana

3. The Orders Amphibia: 1. Anura – examples are frogs & toads 2. Caudata – examples are salamanders & newts 3. Apoda – examples are caecilians • Amphibians are significant because they represent the most primitive vertebrates with four limbs that maintain a terrestrial niche.

4. 3 Examples of the order Anura • There are about 3500 species of frogs and toads. Frog: • Habitat – temperate and tropical climates around the world • Niche – insectivores (eating a diet of insects)

5. 3 Examples of the order Anura, cont’d Toad: • Characteristics – can secrete poison on their skin; appear to have dry, wart-covered skin. • Habitat & Niche – generally same as frogs; perhaps somewhat more terrestrial.

6. 3 Examples of the order Anura, cont’d Salamanders / newts: • Characteristics – also have poison glands; have tails and largely cartilaginous limbs • Habitat – live near water, under moist rocks and logs • Niche – same as frogs and toads

7. General Characteristics • Have no nails or claws • Minimal number of teeth • Most have a tongue that is projectile and sticky • Spends first stages of life in water as tadpoles • They go through drastic changes during development (caused by changes in hormones) • Tadpoles are herbivorous while adults are carnivorous

8. General Characteristics Cont’d • They are ectotherms. During extreme environmental conditions they either hibernate (winter) or aestivate (summer). • Temperature regulation is mainly behavioral • They breathe through poorly developed lungs and moist skin.

9. Amphibians – Systems • Well developed brain attached to the dorsal nerve cord. • They contain a well developed muscular system. • Sensory receptors located all over the skin • Good vision since these animals are mainly vision feeders; that is, they have to use their sight to find and capture food (think of a frog going after a fly!)

10. Amphibians – Reproduction & Reproductive System • Dioecious – 2 different sexes very similar in structure (appearance) • External fertilization in moist environments. Exceptions to the external fertilization are salamanders (only about 10% are external). • Jelly-like eggs need to be laid in water • Interactions between internal (largely hormonal) controls and extrinsic factors determine the timing of reproductive activities. • Their offspring develop through a process called metamorphosis.

11. Vocalization • Sound production is primarily a reproductive function of male anurans. • These calls attract females to breeding areas and to announce to other males that a given territory is occupied. • These calls may also cause some hormonal changes internally to occur, reading the breeding process in females. • Sounds are caused by air being forced from the lungs over the vocal cords and cartilages of the larynx, causing them to vibrate.

12. Our Dissection Froggy The American bullfrog – Rana catesbiana • Typically the specimens are adult male and egg-bearing females, measuring about 7 inches from the tips of their snouts to the ends of the trunks. Their long hind legs, when extended, add another 8 inches to their total length of 15 inches. • Arteries are injected with RED latex, and veins with BLUE or YELLOW latex. • Frogs shown good organization of systems, along with a relatively complete muscular and skeletal system.

13. Special Amphibian Facts • Amphibians have a “double life” because they spend half their life in water and half on land. • In PA waters, the presence of tadpoles and frogs show signs of good environment health.