Amphibians By Sean Ostling and Jessica Wilson

What is an Amphibian? An amphibian is any cold blooded, smooth skinned, tetrapod, vertebrae animal. As babies, they hatch as an aquatic creature. However, it then develops air-breathing lungs as it matures and enters adulthood. They live on land and in water. Amphibians are part of the Kingdom Animalia, Phylum Chordata, and Class Amphibia.

Examples

Polygenetic Tree

Big-Eyed Tree FrogChinese Giant Salamander Chinese Fire Belly Newt KingdomAnimalia PhylumChordata ClassAmphibia OrderAnuraCaudata FamilyHyperoliidaeCryptobranchidaeSalamandridae GenusLeptopelis Andrias Cynops SpeciesL. vermiculatusA. davidianusC. orientalis 5

Life Cycle of the Chinese Giant Salamander Two adult salamanders mate (sexual reproduction). Adult female lays eggs underwater in a plant. Eggs hatch into gilled larva. The offspring cannot breathe on land yet until it’s lungs develop. Once the salamander's lungs have developed, it can move to the land.

Life Cycle of the Chinese Giant Salamander These salamanders live in dark, muddy, rock crevices along riverbanks. They are mostly active at night at eat smaller fish, smaller salamanders, worms, insects, crayfish and snails. Once the salamander is an adult, it will then mate. The Chinese giant salamander has a life span of up to 30 years. They grow up to 1.8 meters long and weigh up to 145 pounds.

Big-Eyed Tree Frog (Diet and Locomotion) Big-eyed tree frog’s diets include small crickets, fruit flies, mealworms, wax worms, and any other insects small enough for them to ingest. Big-eyed tree frogs wait for a passing insect. Once an insect comes, they stick out their long, sticky tongue at a high speed, trapping the insect. Once the insect is trapped, they swallow it whole. Most frogs do not have teeth. The Big-Eyed Tree Frog is commonly known as the “monkey frog” for its jumping abilities. It moves by small and large hops. They are tetrapods.

Fire Belly Newt (Diet and Locomotion) Fire belly newts will eat almost any small insect and invertebrate that they can find. Their diet includes earthworms, bloodworms, spiders, millipedes, and centipedes.

Fire Belly Newt (Diet and Locomotion) The fire belly newt has a long tail and a large fin that allow them to be strong swimmers. Their black back and bright red spotted belly acts as a warning towards other predators. On land, they move by walking on their four legs. They are tetrapods.

Circulation Amphibians have a double-circuited circulation system. The heart is three chambered, which includes the right atria, left atria, and one ventricle. The blood is pumped to the lungs, becomes oxygenated, comes back to the heart, and then is pumped throughout the amphibian body by travelling through veins, arteries, and blood vessels.

Circulation Continued Amphibians are cold blooded. Therefore, they do not need as much energy. Unlike humans, amphibians do not need lots of energy in order to keep their bodies warm. Their body temperature is dependent on the temperature of the environment. The one ventricle in the heart is not efficient, but that is okay for the amphibians because not as much energy is required.

Gas Exchanges 3 ways to breathe: Through their gills Air diffusion through their skin With their lungs They inhale oxygen, and exhale carbon dioxide.

Gills Most amphibians are born with gills and use their gills as babies. For example, tadpoles. As they grow, the gills seal and turn into lungs. However, salamanders and newts keep their gills into adulthood.

Diffusion Through Skin Diffusion through the skin helps amphibians thrive on land and in water. However, it puts them at risk of suffocating if their moist environment becomes dry. Dry skin does not allow oxygen and carbon dioxide transfer. Their permeable skin leaves amphibians vulnerable to toxins in their environment.

Digestive System Amphibians take in food through their mouths by usually swallowing their prey whole with some chewing done in the oral cavity. However, this depending on the species. They can do this because they have very large stomachs. A strong sphincter separates the oral cavity from the esophagus, which is separated from the stomach from another sphincter. The relatively short esophagus is lined with cilia. The cilia helps transfer food into the stomach.

Digestive System Like all mammals, the liver functions as the central metabolic organ that regulates blood sugar. This is a main source of energy for the amphibian. The liver of amphibians also produces the final metabolic products and carries them through the vascular system to the kidneys, and finally to the exit of wastes.

Waste Execration Amphibians get rid of their waste the same way most mammals including humans do. This is by feces and urine. Amphibians have a tubular system. Amphibians also rid themselves of a lot of waste by sweating from their sweat glands. There is lots of waste is in sweat.

Classification Changes There have been no classification changes involving amphibians.

Interesting facts There are between 5,000 and 6,000 species of known amphibians. The first amphibians appeared approximately 370 million years ago. A group of salamanders known as the plethodontids have no lungs.

Interesting Facts Certain frogs can jump up to 20 times their own body length in a single leap. Some frogs and salamanders have tongues 10x the length of their body. Salamanders can re-grow their toes and tails. The world's largest frog is the Goliath Frog. It lives in Africa and can grow up to 33cm and can weigh up to 33 kg.

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