1. Regular Biology Chapter 31 WAGGY
The Amphibians

2. Chapter Objectives 1. List the characteristics of living amphibians
2. Understand the taxonomy of the amphibians
3. Name the three orders of amphibians
4. Discuss the structure & function of the frogs body

3. Characteristics of Amphibians
Amphibians are vertebrates which mean they have an internal skeletal system a dorsal spinal cord & a skull to protect a developed brain
There are about 4,880 species of frogs, toads & salamanders
Their skin is thin & must be kept moist to allow for gas exchange
Most must have water to complete reproductive cycle

4. Taxonomy Domain: Eukarya Kingdom: Animalia Phylum: Chordata
SubPhylum: Vertebrata
Class: Amphibia
Order: There are three:
1. Caudata
2. Gymnophiona
3. Anura

5. Order: Caudata
The salamanders have elongated bodies,long tails & moist skin
They range in length from a few cm to 1.5 m (4.5 ft)
They range from fully aquatic to permanently terrestrial
Salamanders are carnivorous & are active mostly at night

6. Most salamanders live in North America
They lay their eggs in water & when they hatch they are in a swimming larval form which then metamorphose into the adult body form

7. Order: Gymnophiona The caecilians
These are highly specialized legless amphibians that resemble small snakes
Most live in the tropical regions
Range in length from 30cm (12 in) to 1.5 m (4.5 ft)
Caecilians are rarely seen & little is known about their behavior

8. Order: Anura
Frogs & toads are found worldwide except for the polar regions
Most spend at least a portion of their lives in water - some are completely aquatic
Anurans with bumpy skin are typically called toads while those with smooth skin are called frogs

9. The word anura means tailless reflecting that the adults do not have tails
Adults are carnivorous & will eat anything they can catch
Frogs & toads are adapted for jumping

11. The Frog: Skin Serves two important functions: 1. Respiration
The skin is moist & permeable to gases & water
2. Protection
It is covered with mucous glands to maintain the moistness of the skin & to secrete foul tasting substances to deter predators

12. The Frog: skeleton The spine is short & rigid
The forelimbs absorb the shock of landing
The forelimbs attach to a pectoral girdle (the shoulders)
The hindlimbs attach to the pelvic girdle
Both the pectoral & pelvic girdles transfer weight to the legs which are built to handle the stress of gravity