Phylum Chordata Class Amphibia

1.Class Amphibia A. Lay eggs in water, or some kind of moisture 1. Live in water as larvae and on land as adults. 2. Have moist skin B. Feeding 1. Tadpoles – herbivore, Adults are carnivores C. Gas exchange 1. Skin – always needs to be moist, also lungs. 2. Gills – some species D. Amphibians are cold-blooded

E. 3 chambered heart 1. 2 atriums – right side, deoxygenated blood, left side, oxygenated blood ventricle – center, main pumping chamber, up into both atriums. F. Waste 1. Nitrogenous waste are secreted by kidneys 2. Large amounts of dilute urine because of osmosis occurring through the skin G. Limbs 1. 4 limbs stick out sideways a. Exception = legless amphibians 2. Move in an s-shape curve or 3. Use hind legs to jump or 4. Suction like adhesive disks – sticky pads H. External fertilization

Frog’s Heart

Left Atrium Left Lung Body and left lung Body and Right lung Lower body Right Atrium Ventricle

H. External Fertilization 1. Amplexus – male frog climbs on the females back, wraps his arms around her body and uses his large thumbs to push her eggs out. While eggs are leaving the cloaca, male deposits sperm directly on her eggs, fertilizing them as they enter the water.

I.Digestive Track 1. Mouth 2. Esophagus – gullet 3. Stomach 4. Pyloric Sphincter – lower part of stomach 5. Duodenum – upper end of small intestines 6. Ileum – lower end of small intestines 7. Large intestines 8. Cloaca 9. Anus

J. Digestive system accessory organs 1. Liver – produces bile, fat emulsifier 2. Gall Bladder – stores excess bile 3. Pancreas – produces pancreatic juices that secretes into the stomach and small intestines. K. Mesentary – flexible tissue that holds and connects all the organs together inside the frogs body. (Connective Tissue)

2. Order Urodela A. ex. Newts and salamanders B. Size – no longer than 15 cm C. Larvae are fully aquatic with gills and a tail D. 300 species

3. Order Apoda A. ex. caecilians (worm-like amphibians) B. 160 species

4. Order Anura A. ex. Frogs and toads B species C. Some live part of their life in water, some are permanently aquatic. D. Toads can live without water E. Frogs shed their skin and can eat it! F. Anura means tailless G. Return to water to reproduce H. Hatched eggs become tadpoles I. Most go through metamorphosis to become adults.

Frog Cycle 7-10 days tadpole hatches from egg 6-9 weeks legs sprout out 12 weeks tail disappears and adult frog

Differences between a Tadpole and an Adult Frog TadpoleAdult –GillsLungs/skin –TailedTailless –HerbivoreCarnivore

Frogs have variable kinds of eye types. The colored part of the eye is called the iris. They can be brown, green, silver, red, bronze, and even gold. The pupils come in all kinds of shapes too! (2) Round pupils: Some frogs have round pupils just like you and me. Newts and Salamanders also have round pupils. (2) Vertical pupils: Vertical pupils that look like a cats eye are really good for night vision and respond quickly to changes in light. (3) Horizontal-Shaped pupils: These are the more common pupil, good for normal day-vision. Nictitating Membrane – known as the third eye lid of the frog.

F. Frogs hearing 1. Frogs can hear using big round ears on the sides of their head called a tympanic membrane. 2. Tympanic means drum. 3. The size and distance between the ears depends on the wavelength and frequency of a male frogs call. 4. On some frogs, the ear is very hard to see!

G. Frog colors 1. Bright colors signifies a warning – saying “I’m poisonous” 2. Other colors are for camouflage to hide from predators.

Mouth structures Maxillary – Row of teeth on the upper jaw. Vomerine – a pair of teeth, Between nostril holes inside mouth on upper palate. Glottis – pathway to the lungs. Esophagus – pathway to the stomach Fatty bodies - Lose fat noodles that insulate frog and protect organs. Rib cage – no a frog lack ribs.