Amphibians are fascinating creatures that fall under the Chordata phylum and are a part of the Animalia kingdom. They are multicellular vertebrates with the unique ability to thrive in both terrestrial and aquatic environments. With about 3000 species, they were the first cold-blooded animals to make land their home.
Meet the Amphibians
Let's delve into the unique features that define the class Amphibia:
Amphibians are capable of living both on land and in water.
These creatures are ectothermic, typically found in warm environments.
An amphibian’s body is divided into a head and trunk, and may or may not have a tail.
Their skin is moist and can be smooth or rough, but it lacks scales.
They do not possess paired fins, though unpaired fins may be present.
They have two pairs of limbs for movement.
Respiration in amphibians occurs through the lungs and skin. Some adults may also have external gills.
They have a three-chambered heart.
The kidneys are mesonephric and excrete ammonia and urea.
They have ten pairs of cranial nerves.
During their development, a lateral line is present.
Amphibians have separate sexes and usually undergo external fertilization, but salamanders have internal fertilization.
Their development involves metamorphosis.
Breeding happens in water and males lack copulatory organs.
Further Reading: All About Frogs
Amphibians are categorized into three distinct orders, as outlined below:
“Apoda” translates to “without legs”. These creatures lack limbs and have scales on their bodies.
Often referred to as “blind-worms”, their eyes are concealed by skin or bone.
They have tentacles on their heads, which are chemosensory organs that help detect prey underground. Example: Rubber Eels
They have venom glands.
They secrete mucus to prevent water loss.
These are creatures with tails.
They have elongated bodies and four limbs of equal size.
Their skin is smooth and contains poison glands.
Fertilization is internal in these species.
They feed on insects and worms. Example: Newts
They can be found in soil, under leaf litter, or in water.
In the southern US, they primarily reproduce in the winter.
Males and females show little differentiation.
Spermatophores are used for internal fertilization.
They have concealed gills.
There are approximately 3400 species of Anura worldwide.
They have four limbs, with the front ones elongated and adapted for jumping.
The head and trunk are fused.
The tail is present in the larval stage but disappears in adults.
Fertilization is external and eggs are laid in water. Example: Frogs and toads.
For additional information on the class Amphibia, explore more resources.
What are the characteristics of class Amphibia?
Amphibians can live both on land and in water, are ectothermic, and have bodies divided into a head and trunk. They have smooth and rough skin without scales, no paired fins, two pairs of limbs for locomotion, and respire through lungs and skin. Their heart is three-chambered, and they possess ten pairs of cranial nerves.
How are amphibians classified?
Amphibians are divided into three orders: Apoda (Gymnophiona or Caecilia), Urodela (Caudata), and Anura (Salientia).
What are some examples of class Amphibia?
Frogs, Salamanders, and Caecilians are examples of class Amphibia.