Difference between Reptiles and Amphibians

The main Difference between Reptiles and Amphibians is their behavior towards the water. Amphibians spend a part of their life in water. Frogs are the best example of amphibians. Frogs spend their primitive stage in water. As tadpoles, they live in water. On the other side, snakes are reptiles. Snakes like Northern snakes live in water, but not all snakes prefer to stay in the water. Many snakes live in the desert region too.

Similarities between Reptiles and Amphibians

Reptiles and amphibians share some similarities which create confusion to decide the class of species. Reptiles include turtle, lizard, crocodiles, snakes while amphibians include frogs, salamander, toads, newts. They both are Ectothermic i.e cold-blooded. They need external heat sources to maintain body temperature.
Let’s have some detail differences between reptiles and amphibians.

Reptiles vs Amphibians

Sr No.	Character	Reptiles	Amphibians
1.	Introduction	Reptiles are animals that spend their life on land, breathe air, and lay eggs.	Amphibians are a group of animals that live on land as well as in water.
2.	Breathing Method	Lungs	Lungs and gills
3.	Safeguarding	They secrete toxins through nails, teeth. Some have poisonous teeth and nails. Reptiles have a scale to protect in physical defense.	They can bite, secrete toxic from the skin..
4.	Evolution	They are miniature adult look alike when born.	Breathes through gills primitively until it develops lungs.
5.	Fertilization	Internal fertilization and they are oviparous as well as viviparous.	External fertilization and they are oviparous.
6.	Skin Type	Skin is dry, hard and covered with keratin scales	Skin is smooth, moist, and sticky with high porous.
7.	Eggs	Eggs are covered with hard protecting shell. They lay eggs on land or keep in bodies until hatch.	Eggs are covered with gel without any hardcover. Usually, they lay eggs in water or damp places.
8.	Heart Structure	Reptiles have a 3-chambered heart (3 chambers but 1 ventricle further divided through a spectrum.	Amphibians have a 3-chambered heart.
9.	Limbs	Reptiles have limbs to run and swim. Some have no limbs (snake). Some walk slow or crawl while some can run, jump, climb.	They have webbed limbs that help them to swim.
10.	Example	Snakes, Lizards, Turtles, Crocodiles, Birds(technically)	Frogs, Salamanders, Toad, Newts.

Evolution of Reptiles and Amphibians

Reptiles

The oldest unquestionable known reptile was Hylonomus. The origin of these reptiles lies about 300 millions year ago. It was about 8 to 12 inches long about 20 to 30 centimeters, a small lizard-like animal. Hylonomus was reptile with numerous sharp teeth as an insectivorous diet animal. The true reptiles were known as Anapsids and Diapsida. Turtles are believed to be anapsids.

They were categorized as having a spinal cord, strong solid skull, holes only for nose, eyes, etc. On the other hand, Diapsida has a pair of holes located behind the eyes higher on the skull. They further are divided into lepidosaurs and archosaurs. Lepidosaurs include snakes, tuataras, lizards whereas, archosaurs include crocodiles and birds.

Amphibians

The origin of amphibians lies about 350 million ago. From sarcopterygian which was similar to modern rhipidistian fish belonging to the subclass Dipnoi. These amphibians were around 195 cm long which is rare now. These lobe-finned fish have developed multi-jointed fins which helps them to crawl at the bottom of the sea.

Some fishes develop lungs at the earliest which helps them to breathe. Their bony fins evolve into limbs and could be used to hoist themselves out of the water and onto dry land in any circumstances if required.

These include mammals, birds, reptiles. Despite being able to crawl on land, few of them still spent most of their time in the water. The study of these amphibians is known as batrachology. Examples are frogs, salamanders, newts, toads.

Types of Amphibians

Amphibians have three main categories urodele, anurans, gynophores. The urodeles include salamanders and newts, anurans include frogs and toads, gynophores includes caecilians.

On the other hand, reptiles have three main categories Crocodilia, Squamata, Testudines, Rhynchocephalia. Crocodilia includes crocodiles and alligators. Squamata includes lizards, snake. Testudines includes all turtles.

Differences in Physical Attributes

Reptiles and Amphibians differ in many physical attributes. Amphibian’s skin is smooth and sticky with high porous, whereas reptiles have water-proof, dry, hard, and keratin covered skin.

Most of the amphibians have lungs and gills on their skin used to breathe. On the other hand, reptiles have only lungs to breathe air. Limbs and lungs make them different from reptiles. This allows them to live in water as well as on land. Reptiles usually stay on land.

Compared to reptiles, amphibians are oviparous, whereas reptiles are oviparous as well as viviparous. Reproduction takes place due to internal fertilization in reptiles but amphibians are dependent on external fertilization.

Reptiles have four-chambered heart, in which two are arteries and two are ventricles. Amphibians have a three-chambered heart. Reptiles can visualize and understand the difference between colors. Amphibians cannot distinguish between colors as they are restricted to narrow bands of the color spectrum.

Apart from these differences, reptiles, and amphibians come under the same class Reptilia. This is the reason they share many anatomical and psychological similarities. They belong to the same taxonomic category and sub-taxonomic category. They are cold-blooded and disguise for protection from predators.