Amphibians Class Amphibia Amphibians Animals that can live

Amphibians Class Amphibia

Amphibians • Animals that can live on land in water Chinese Giant Salamander

Amphibians • First animals with four limbs • Tetrapods: vertebrates that have four limbs.

Acanthostega • Found in 360 million year-old rocks in Greenland • Had lungs and eight-toed legs, but also had gills and a lateral line system.

Fish to Amphibian Transition

Adaptations help amphibians live on land • Large shoulder and hip bones help support more weight.

Adaptations • Interlocking projections on the vertebrae help keep the backbone from twisting and sagging.

Adaptations • Mobile, muscular tongue allows amphibians to capture and manipulate food.

Adaptations • Development of a middle ear help some amphibians hear out of water.

Adaptations • Breathe through the skin or with the use of gills or lungs

Adaptations • Amphibians have a three-chambered heart

Amphibians return to the water to reproduce • Eggs do not have shells

Strategies to keep eggs wet: • • Laying eggs directly in water Laying eggs on moist ground Wrapping eggs in leaves Brooding eggs in pockets on the female’s back

Pygmy Marsupial Frog Flectonotus pygmaeus

Tadpoles • Some frogs start as tadpoles • Have gills and a broad-finned tail

Amphibian Metamorphosis • Change in form and habits of an animal • It affects nearly every organ in the tadpole’s body

Tadpole into Adult Frog • Gills are reabsorbed and lungs develop • Circulatory system is reorganized to send blood to the lungs • Tail fin is reabsorbed

Tadpole into Adult Frog • Body grows limbs and completely reorganizes its skeleton, muscles, and parts of the nervous system. • Digestive system is rebuilt to handle a carnivorous diet.

Three Groups of Modern Amphibians • Salamanders • Frogs • Caecilians

Salamanders • More than 300 species • Long body • Four walking limbs • tail

Salamanders • Walk with a side-to-side movement that may be similar to ancient tetrapods • The largest family of salamanders do not have lungs, so they exchange gases through the lining of their skin and mouth.

Family Plethodontidae • Lungless salamanders • Most common kind

Salamanders • Larvae and adults are carnivores Invertebrates Insects Worms Snails Vertebrates Fish Frogs

Frogs • Over 3000 species • Largest group of living amphibians

Adult Frogs • • • Tailless bodies Long, muscular hind limbs Webbed feet Exposed eardrums Bulging eyes

Adult Frogs • Bodies adapted for jumping – Elongated bones in their hips, legs and feet for increased speed and power – Hind legs have fused bones that absorb the shock of landing

Toads • One family of frogs • Rougher, bumpier skin • Shorter legs- not good jumpers • Glands make toxins that protect them from predators – also in tropical frogs

Frogs • Live in every environment on Earth except at the poles and the driest deserts.

Caecilians • Legless, burrowing amphibians • Live in the tropics, such as South America

Caecilians • 160 species • Range from 4 inches to 5 feet • Banded bodies that make them look like giant earthworms

Caecilians • Are predators • Search for earthworms and grubs • Have no arms or legs for burrowing, so have to move like an earthworm. • Use hydrostatic skeleton to stiffen it’s body and drive its head forward like a battering ram.