Kingdom Animalia; Phylum: Chordata (Chordates), Subphylum: Vertebrata (Vertebrates)
Class: Amphibians (Amphibia)
The Amphibians create a link between terrestrial and water vertebrates. There are several stages throughout their lives. The larval stage is undergone in water while larvae have to breathe with their gills. Mature animals use lungs in order to breathe the atmospheric oxygen. Many times breathing with lungs is not sufficient so skin breathing is used as well. The skin is smooth and contains a number of sweat glands.
Evolution: Amphibians are over 300 million years old. Therefore there is a huge variety of species. So far there are described over 3 000 different species.
Anatomy: The amphibian skeleton is mostly made of bones. The backbone is the base and is made of vertebrae with their prominences. We can also observe a skeleton which includes extremities. Ribs still remain underdeveloped.
Physiology: The amphibians use lungs for their breathing. Breathing is very unique as there is no chest and thorax breathing muscles. Therefore they have to inhale by swallowing. The blood circulation is different when compared to fish. Their heart consists of two atriums and one ventricle. Deoxygenized blood from the body comes to the right atrium and consequently flows into the ventricle. The oxygenized blood from lungs comes to the left atrium and flows to the one ventricle as well. This means that there is a mixture of oxygenized and deoxygenized blood in the ventricle. A certain amount of this mixed blood comes to the lung for oxygenation and another amount flows into the body circulation. Here we can observe two different blood circulations: a lung circulation and a body one. Apart from other crucial functions, the blood is also used for remaining the body temperature. However amphibians’ body temperature depends on the temperature of the environment the amphibian lives in, they are ectothermic animals. The amphibians also have got middle ear as well as an inner ear.
Life span: These vertebrates lay eggs into the water. Here the tiny larvae undergo their first stage while breathing with gills. Later on gills are replaced by lungs and a tail fin is vanished. Two pairs of extremities are being created. Small larvae feed on plankton and vegetables whereas mature animals feed on animal food.
We can divide the Amphibian class into two groups: newts and frogs. Newts ( Cudata): inhabit freshwaters and damp places. As their name already reveals they have got a tail (Latin: cauda means a tail). It includes Salamandra salamandra or Triturus vulgaris. Frogs (Ecaudata): do not have any tail. This group includes Bufo Bufo, Rana temporaria or Bombina bombina.
As we can see there is a vast number of different species which differ in colour, size, reproduction, life span, vocalization, behaviour, food habits and so on. Some species may even produce poison in their skin glands. On one hand many new species are still being discovered but on the other hand some species are on the brink of extinction or endangered.
Agile Frog ( Rana dalmatina )
American Toad ( Bufo americanus )
Axolotl ( Ambystoma mexicanum )
Black alpine salamander ( Salamandra atra )
California Newt ( Taricha torosa )
Common Frog ( Rana Temporaria )
Darwin’s frog ( Rhinodema darwinii )
European Fire-bellied Toad ( Bombina bombina )
European Green Toad ( bufo viridis )
European Pond Terrapin ( Hyla arborea )
Golden Arrow-poison frog ( Dendrobates auratus )
Golden Mantella ( Mantella aurantiaca )
Golden Poison-dart Frog ( Phyllobates terribilis )
Hairy frog ( Astylosternus robustus )
Hochstetter’s Frog ( Leiopelma hochstetteri )
Horned Toads ( e.g.: Phrynosoma douglasii )
Chacoan Monkey Frog ( Phyllomedusa sauvagii )
Marsh Frog ( Rana ridibunda )
Moor Frog ( Rana arvalis )
Paradoxical frog ( Pseudis paradoxus )
Rain Frog ( Breviceps adspersus )
Sharp-ribbed salamanders ( Pleurodeles waltl )
South African Sharp-nosed Frog ( Ptychadena oxyrhynchus )
Southern Toad ( Bufo terrestris )
Surinam Toad ( Pipa pipa )
Tiger Salamander ( Ambystoma tigrinum )
Tomato Frog ( Dyscophus antongilli )
Western Chorus Frog ( Pseudacris triseriata )
Yellow-striped Poison Frog ( Dendrobates truncatus )