Amphibians- Classification Study Guide


Animals that can survive in aquatic and terrestrial environments are called amphibians (class Amphibia). The term amphibian, derived from the Greek amphibios, which means “living a double life,” represents this dual life strategy—though some species are permanent land residents, while others live entirely in the water. There are around 8,100 species of amphibians alive today.


Characteristics of Amphibians

  • These may survive on land as well as in water.
  • They are ectothermic creatures that live in warm climates.
  • Their body is separated into two parts: the head and the trunk.
  • There may or may not be a tail.
  • The skin is smooth and rough, with no scales and glands that keep it wet.
  • They don’t have any paired fins.
  • Unpaired fins are possible.
  • For movement, they have two sets of limbs.
  • They breathe through their skin and lungs.
  • Gills may be seen on the outside of certain species.
  • The heart is made up of three chambers.
  • The kidneys are mesonephric in shape.
  • Ammonia and urea are among the excretory materials.
  • They have a total of 10 pairs of cranial nerves.
  • During their development, they have a lateral line.
  • The sexes are distinct, and fertilization is normally done externally.
  • A metamorphosis is a form of indirect development.
  • Water is where breeding takes place.
  • Males do not have copulatory organs.
  • For example, frogs and salamanders.

Classification of Amphibians

The Amphibians are classified into three orders, which are listed below:

  1. Apoda (Gymnophiona or Caecilia)
  2. Urodela (Caudata)
  3. Anura (Salientia)

1. Apoda (Gymnophiona or Caecilia)


  • Apoda is Latin for “without legs.” These creatures lack limbs and have scales on their bodies.
  • Because their eyes are covered by skin or bone, they are sometimes known as “blindworms.”
  • The tentacles on their heads are chemosensory organs that aid in detecting subsurface prey. Caecilians, for example.
  • They have venom glands.
  • To prevent water loss, they release mucus.

2. Urodela (Caudata)

  • These are the creatures that have a tail.
  • The body is elongated, with four limbs of similar size.
  • The skin is smooth and covered in poison glands.
  • Internal fertilisation occurs.
  • They consume insects and worms. Salamanders, for example.
  • They can be found in leaf litter, dirt, or water.
  • They typically breed in the southern United States throughout the winter.
  • There are very few distinctions between males and females.
  • Internal fertilization is accomplished with the use of spermatophores.
  • They have concealed gills.

3. Anura (Salientia)

  • There are over 3400 Anura species in the world.
  • They are four-legged. In order to leap, the front limbs are extended and changed.
  • The head and trunk are joined at the hip.
  • The tail is only present in the larval stage and is absent in adults.
  • External fertilization occurs, and the eggs are placed in water. Frogs and toads, for example.


  • Several distinguishing characteristics characterize modern amphibians.
  • They have wet skin and rely significantly on cutaneous (skin-surface) respiration. They have a two-channel hearing system, green rods for color discrimination retinas, and pedicellate (two-part) teeth.
  • Some of these characteristics may have existed in extinct populations as well.
  • The amphibian phylum is covered under Chordate.


1. How do you classify amphibians?

Organisms in the class Amphibia belong to the Chordata phylum of the kingdom Animalia. These are multicellular vertebrates that can live on land as well as in water. This class contains around 3000 species. They were the first cold-blooded creatures to exist on land.

2. What are the 7 main characteristics of amphibians?

1. External Fertilization: Amphibians do not need to mate before releasing their eggs into the water. They reproduce by laying transparent eggs with a jelly-like texture.

2. Grows With 4 Legs: With a few exceptions, the vast majority of amphibians have four legs.

3. Cold Blooded: The amphibian, like reptiles and fish, is cold-blooded. They can adjust their internal temperature to match the temperature outside. As a result, these creatures keep their surroundings from harming their bodies.

4. Carnivorous appetite: Every type of amphibian is a carnivore. If it’s tiny enough, they’ll eat whatever they can get their hands on. Some toad species will even consume mice.

5. Primitive lungs: The lungs of all amphibians change due to the evolution that happens during metamorphosis. They must serve as gills while the animal is submerged, but as adults, they allow them to breathe straight through the skin.

6. Lives on water and land: When amphibians are born, they spend their first days in the water. Their natural development, however, forces them to reside mostly on land. These creatures require a damp habitat, whether on land or in water.

7. Vertebrates: Every amphibian, no matter how little it is, has a backbone. This backbone begins as cartilage and changes as the rest of the organs undergo metamorphosis.

3. What are the 4 classes of amphibians?

This category includes:

  1. Frogs
  2. Toads
  3. Salamanders
  4. Newts

Through their extremely thin skin, they can all breathe and absorb water. Amphibians have unique skin glands that create important proteins.

4. What are amphibians in short?

An amphibian is a cold-blooded vertebrate born in water and breathed through gills. As the larva develops into an adult, its lungs gain the capacity to breathe air, and the animal can survive on land. Amphibians include frogs, toads, and salamanders.

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  1. Amphibian Classification – Advanced. Accessed 3 Dec, 2021.
  2. Amphibian Classification. Accessed 3 Dec, 2021.
  3. Amphibian Classification. Accessed 3 Dec, 2021.

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