Amphibians Animals with a double life
Primary Characteristic Amphibians have a completely aquatic larvae which transforms into an air breathing, semi-terrestrial adult.
Three orders of Amphibians • Caudata: salamanders & newts • Anura: frogs and toads • Apoda: caecilians
Characteristics of Amphibians • Undergo metamorphosis (change) • Thin, moist skin • Four legs • No claws on toes • Three chambered heart • Rely on water for reproduction • Ectothermic
Thin, Moist Skin • Many amphibians breathe some through their skin • Some salamanders ONLY breathe through their skin • Reptiles have dry, scaly skin
Four legs with no claws on toes Reptiles have claws and sometimes no legs
Three-chambered Heart • The amphibian heart is inefficient • Oxygenated and deoxygenated blood gets mixed together in the 3rd chamber
Why amphibians breathe through their skin • Because the heart mixes blood, they must take in extra oxygen through their skin • The skin must remain moist for gas exchange
Water needed for reproduction • Fertilization usually external • Water needed as medium for transporting sperm
Body temp changes with the temp of environment Regulates body temp through behavior Become dormant in extreme heat or cold Ectotherms
Metamorphosis: Frogs • Frog eggs hatch into tadpoles with: • Fins • Gills • two-chambered heart • Tadpoles grow into adults with: • Legs • Lungs • three-chambered heart
Metamorphosis: Salamanders • Larvae have: • Gills • tail fin • Adults: • Have no gills • Have no tail fin • Breath through moist skin or lungs.
Caudata: Salamanders • Long, slender body with a neck and tail. • Look like lizards, but have smooth, moist skin and lack claws. • One fourth breathe through skin and have no lungs. • Most have four legs, but some have only 2 front legs.
Newts vs. Salamanders • Newts are salamanders that live entirely in water.
Local Salamander Species Eastern Red Spotted Newt , Slimy salamander, Blue Ridge two-lined salamander
The Hellbender • Largest salamander in North America, and one of the largest in the world. • Up to 29 in. long • Live in rivers and large, swift streams
Anurans: Frogs • No tails • Jaws and teeth • Vocal cords capable of producing a range of sound • Use sound to find a mate • Breathe through lungs or skin
Frog Songs • Vocal cords capable of producing a range of sound • Vocal cords = band of tissues in the throat • Use sound to find a mate • Frogs can be identified by their songs
Dart Frogs • Secrete toxic chemicals through skin as a defense against predators. • Some have enough toxins to kill 10 people • Bright colors act as warning coloration
Cane Toads • Imported to Australia to eat beetles • Toxic to fish and animals • Secretes toxin from glands • Causing reduction in wildlife
Frog Leaping • Frogs can jump over 20 times their own length • That is like a person jumping 100 feet!
Frog Respiration Breathe through lungs or skin
Sensitive to Environmental Changes • Are indicator species for pollution in land, air, or water. • Declining numbers or deformities indicate an unhealthy environment.
Frogs: Long, hind legs Smooth, moist skin Toads Bumpy, dry skin Short legs Frogs vs. Toads
Local Species: American Toad • Poison glands in paratoid gland behind ears • Squirts milky poison at predators (like dogs)
Local Species: Fowler’s Toad • Common in U.S. • Call sounds like the bleat of a sheep
Southern Cricket Frog • Dark triangle between the eyes • Call sounds like a series of cricket-like clicks • Tiny – less than 1-1/4 inches long
Common Local Frogs Spring Peeper • One of the first songs of the spring • Call is a high-pitched whistle with a trill
Eastern Narrowmouth Toad • Sounds like a bleating sheep • Good at burrowing in soil or leaf litter
Bullfrog • Largest frog in North America • Eat crayfish, insects, birds, fish • Harvested for legs, which are eaten
Green Frog • Sounds like the twang of a loose banjo string • Can be green, bronze, or brown
Southern Leopard Frog • Has a light spot in the center of the eardrum • To escape predators, dives in water, makes a sharp turn, and returns to original shore to hide
Apoda: Caecilians • No limbs, short or no tail • Tropical • Look like worms • Small eyes and often blind when eyes are covered by skin • Eat earthworms and other invertebrates in soil
What is this? 1 2 3 4
Quiz • What does the word, “amphibian” mean? • What are the three classes of amphibians? • How are amphibians different from reptiles? • How are amphibian frog larvae different from the adult frogs? • Where do caelilians live? • Why do many amphibians need to have moist skin?
Quiz • What is an ectotherm? • What kind of salamander is pictured to the right? • What is the largest salamander in North America? • How are frogs different from toads? • Why are frogs such good indicator species, and what does this mean?
Quiz • What kind of amphibian has no legs, often has no eyes, and can be found in tropical environments only? • What is the purpose of the bright skin in a dart frog? • What is the main purpose for a frog song? • What are 3 functions for a cloaca? • What is the function of the tympanic membrane and where is it on the frog? • Where would you find the nictitating membrane?
Name the species: AB CD