AMPHIBIANS
Kingdom: Animalia
Phylum: Chordata
Animals with a backbone

Phylum Chordata
• Classes:
– Amphibia
– Reptilia
– Aves
– Chondrichthyes
– Osteichthyes
– Mammalia

General Characteristics
• It is an animal in
Kingdom Animalia,
Phylum Chordata,
Class Amphibia
• Most lay eggs in
WATER.
• It is an ECTOTHERM
– body temperature is determined by environment
(opposite =
Endotherm )

Salamander vs. Newt

Which one is an amphibian?

What’s the difference?
• Toad vs. Frog

Life Cycle
• Begin life as an Egg mass (Eggs are
Moist , not Hard )
• Go through
Metamorphosis
• Egg to Tadpole to
Tadpole frog to
Young frog to Adult frog
• External Fertilization

Respiratory System
• Begin their lives with gills and most end their lives with lungs.
• Some can breathe through their skin – their skin is permeable (allowing materials to flow in the frog to out of frog)
• So…how does the oxygen get in our blood?

Let’s take a look at Humans…
• 4 chambered heart
• Very efficient
• Let’s label…
– Right ventricle
– Left ventricle
– Right Atria
– Left Atria
– Aorta
– To lungs (not oxygenated)
– From lungs (oxygenated)
– To body (oxygenated)
– From body (not oxygenated)

Cardiovascular System
• Frogs have a 3 chambered heart
• Consisting of 2 atria and 1 ventricle .
• Lungs help to oxygenate the blood and also take out carbon dioxide

Digestive System
• Mouth – break down of food
• Gullet
• Esophagus
• Stomach – break down of food
• Small intestine – food is digested and absorbed
• Liver makes bile; gall bladder stores bile
• Pancreas secretes enzymes to break down food
• Large intestine – water is absorbed
• Cloaca – excretes exit

Digestive System
• Accessory organs help to digest food
• Liver – makes bile
• Gall bladder – stores bile
• Pancreas – secretes enzymes to help with digestion

Excretory System
• Kidneys – remove toxins from blood
• Toxins travel through the ureter (tube) until it reaches the bladder.
• Bladder holds the urine until it is excreted through the cloaca.

Importance
• Amphibians help us to monitor the environment
• Check the handout for more information

Frog Malformations