Chordate Classes The Amphibians Pgs. 382-386

Amphibian Body Characteristics Body Symmetry: Bilateral Cell Organization: Cells to tissues to organs to organ systems Reproduction: Sexual Body Development: “Double Life” Metamorphosize to adult

Frogs, Salamanders and Newts, and Toads Three Orders of Amphibians Frogs, Salamanders and Newts, and Toads

Caecilians – a rare legless amphibian Just the facts… Name means “double life” Begin life in water, live on land, return to water to reproduce. Are ECTOTHERMIC VERTEBRATES Caecilians – a rare legless amphibian Newt

Just the Facts… Skin lack scales, feathers, and hair Must remain moist Feet have no claws 3-chambered heart The endangered Asian Giant salamander can grow up to 5 feet long!

Amphibian Metamorphosis – “Double Life” Fertilization in frogs and toads is EXTERNAL Fertilization is INTERNAL in most salamanders Salamander Life Cycle

Frog Life Cycle Eggs are laid on or in water Tadpoles live in fresh water and breathe with gills Grows legs, loses its tail Adapts to land by breathing with lungs Life isn’t easy for a tadpole!

Life on Land How do amphibians breathe? How do amphibians get food? How do amphibians move?

How do Amphibians Breathe? Most amphibians lose their gills and develop lungs. O2 and CO2 is also exchanged through their skin. The Axolotl is the larva form of a salamander. It is at this stage that it breathes through gills; a mature adult breathes through lungs and its skin.

Moving Oxygen Through the Body Three chambered heart Path of Blood Heart Lungs Body Called a “double loop” Happens in most vertebrates

How do Amphibians Eat? Tadpoles are HERBIVORES Adult Amphibians are CARNIVORES Insects, worms, slugs, etc. Goliath frog eating another frog.

How do Amphibians Move? Salamanders crawl Frogs and Toads have adaptations for jumping and swimming Shock absorbing skeleton Powerful hind legs Webbed hind feet for swimming

Frog Facts!

Comparison of a Frog and a Toad

Frog Mouth

Frog Digestive System Mouth Esophagus Stomach Small Intestine Large Intestine Anus

Amphibian Systems - Circulatory 3 –chambered heart 2 lungs

Amphibian Systems - Nervous Brain and Spinal Cord Optic (eye) nerve

Why Study the Frog? Many systems of the frog are similar to ours. So by studying the frog, we in turn, learn more about ourselves and the anatomy of the human species. Remember, biology is the study of life. The frog dissection is just one step of many steps that takes us closer to learning about the details of human life.