Amphibians Characteristics of Amphibians are eukaryotic heterotrophic vertebrates

Amphibians

Characteristics of Amphibians are eukaryotic, heterotrophic vertebrates They have thin, smooth, moist skin. Some of them have fish-like scales and none of them have claws. They are ectothermic (coldblooded). They have external gills and lungs.

Characteristics of Amphibians Most amphibians have a two-part life cycle. They complete a metamorphosis. The embryo develops into an aquatic larva called a tadpole. The tadpole breathes through feathery external gills. The tadpole develops lungs and limbs during maturation.

Fossil Record Amphibians evolved from ancient ancestors of lungfish. Early amphibians gave rise to reptiles (reptiles evolved from amphibians).

Adaptations to Land Amphibians were the first vertebrates to face the challenge of life on land. They are found in moist environments which prevents dehydration. They absorb and lose water through their skin. They do not drink water.

Modern Classification The three major groups of amphibians are: Caecilians (resemble worms/snakes) Salamanders Frogs (includes newts) and Toads

Caecilians Structure and Function Caecilians are legless and are shaped like worms or snakes Most caecilians have thin, moist skin, while some have bony scales Many have small eyes beneath the skin and are blind.

Caecilians Habitat Caecilians are found only in tropical environments (Asia, Africa, South America). They make up the smallest percentage of amphibians. They live in damp soil. Caecilian Facts Video

Salamanders and Newts Structure and Function They are the most prehistoric amphibians. They have a slender, long body and tail They have four short legs. Their cells can regenerate some body parts (limbs and organs). They can be aquatic or terrestrial. The terrestrial salamanders develop lungs. The aquatic ones retain gills (few).

Salamanders and Newts Habitat Most live under stones or logs in damp wooded areas. Aquatic salamanders never leave the water.

Frogs and Toads External Structure and Function They are highly adapted for life on land. They have powerful leg muscles for fast escapes. Three eyelids: Fleshy upper-eyelid Thin lower-eyelid Nictitating Membrane (Goggles) 1. For use underwater 2. Allows frog to see clearly

Frogs and Toads Vocal sac for calling (males) Webbed feet (True frogs) Adaptation for swimming Toe pads and webbing (Tree frogs/arboreal) No webbing (Toads) Paratoid glands – to release poison (Toads) Warts (Toads) Raised skin Rougher, drier skin

Frogs and Toads Internal Structure and Function Teeth - two sets Maxillary Vomerine Point teeth inward to prevent prey from escaping Tongue Attached to the front end of the mouth Glottis – air passage to the lungs Esophagus – for swallowing food (whole) Fat bodies – used for storing fat during hibernation or breeding

Frogs and Toads Liver Made up of three lobes (sections) Surrounds the heart Heart Two chambers/single loop system (tadpoles) Three chambers/double loop system (adults)

Frogs and Toads Habitat They are found all over the world (from deserts to rainforests) Some arboreal (tree frogs). They make up 90% of all amphibians.

Amphibian Videos Giant Salamanders Rain Frogs Tree Frogs African Bullfrog Fight