There are a total of 1.5 -1.8 million organisms in the world, and they need to be classified. It is said that every organism has come from the same ancestors. It was said that the first organism was just a cell which later showed evolution. The organism showed different variations and evolved into different organisms. Many features make reptiles and mammals different organisms.
Reptiles vs Mammals
The main difference between Reptiles and mammals is that reptiles are oviparous, and mammals are viviparous. The reptiles have scales over their bodies, and mammals do not have scales. The reptiles are cold-blooded animals, whereas the mammals are warm-blooded animals. The mammals have mammary glands to feed their young ones, but the reptiles do not have such features.
Reptiles are the animals mostly terrestrial animals, carnivorous. They have bilateral symmetry, which means they can be cut into two same halves. They are cold-blooded animals which refer to the animals who can not maintain their body temperature. The reptiles also have scales on their body. The reproduction is by a sexual mode, and fertilization is internal.
The mammals are the terrestrial animals and herbivores, carnivores. They have bilateral symmetry and have lungs as their respiratory organ. They are warm-blooded. That’s why they can maintain their body temperature even if the environmental temperature changes. The mode of reproduction is sexual, and fertilization is internal.
Comparison Table Between Reptiles and Mammals
| Parameters of Comparison | Reptiles | Mammals |
| Body features | The reptiles have a body divisible into four regions: neck, trunk, tail, and head. | The mammals have a body divisible into four regions: head, trunk, tail, and neck. |
| Limbs | The reptiles have two pairs of limbs and some even lack limbs. | The mammals have two pairs of limbs with five dights on every limb. |
| Heart structure | The reptiles are three-chambered but only crocodiles are the exception which has a four-chambered heart. | The mammals have four-chambered hearts and they are warm-blooded animals. |
| Excretion | The reptile’s metabolic waste vary from species to species like crocodiles are ammonotelic, snakes are uricotelic, and many more metabolic wastes are excreted based on the habitat of the organisms. | The mammals’ metabolic wastes are urea and thus they are ureotelic organisms. |
| Young ones | The reptiles give birth to the young ones indirectly which means they first lay eggs and then the young ones are born. | The mammals give birth to the young ones and they have special glands called mammary glands to feed the young ones. |
| Examples | Snakes and crocodiles. | Humans, Dogs, and Cats. |
What are Reptiles?
Reptiles are animals that are vertebrates and are mostly found in dry places. They are mostly terrestrial, cold-blooded animals. They are oviparous animals that lay eggs to give birth to young ones. In reptiles, parental care is almost absent. Some of the reptiles even eat their children like snakes. They have scales all over their bodies. Their skin is dry as they lack glands.
The reptiles respire through the lungs and are cold-blooded animals. They have a heart that is three-chambered as they lack sinus venous, whereas crocodile is an exception in the reptiles as it has four-chambered hearts. This gives evidence that the reptiles were the organism that showed the variations and evolved the advanced phylum of the animal kingdom.
The reptiles have a bony exoskeleton. They have a brain that consists of twelve cranial nerves. These reptiles have internal fertilization, and the young ones resemble their adults; therefore, there is no metamorphosis. The Red blood cells in the reptiles are oval and nucleated. It is said that the dinosaurs are the ancestors of the reptiles as they also have scales over their bodies and many physical traits are also similar, providing evidence.
What are Mammals?
The mammals are terrestrial, warm-blooded organisms. They are viviparous organisms mans they give birth to the young ones. They also have special glands to feed the young ones called mammary glands. The mammals have skin that consists of glands that are all useful in removing excess water, salts, minerals, and oil from the body.
The mammals respire through the lungs and have four-chambered hearts. The four-chambered heart allows the pure double circulation of blood and avoids the wastage of energy that occurs by the mixing of blood. Mammals are considered as the highly advanced organisms in the animal kingdom. The mode of nutrition is mixotrophic. They can be herbivorous or carnivorous, and even omnivorous.
The mammals have an exoskeleton that includes skin, hair, nails, and many more components. The brain in mammals has twelve cranial nerves along with the cerebrum and cerebellum. The senses are very well developed in mammals. They have a pinna in the ears that help to collect sound from the environment and conduct it to the ear. The red blood cells in the mammals are biconcave and non-nucleated except camel.
Main Differences Between Reptiles and Mammals
- The mammals are warm-blooded animals, whereas the reptiles are cold-blooded animals.
- The reptiles have scales over their bodies, but the mammals do not have scales over their body.
- The reptiles are oviparous, while the mammals are viviparous.
- The mammals have glands over their skin, but the reptiles lack such glands.
- The mammals have four-chambered hearts bit the reptiles have three-chambered.
Conclusion
The reptiles and mammals belong to the different phylum of the animal kingdom. Even if they are both chordates, there are still many features in which they differ from each other. The mammals are the highly advanced organisms of the animal kingdom. They have the maximum cranial capacity. Whereas the reptiles are said to be evolved from the dinosaurs.
The reptiles have scales all over their body as dinosaurs. They even have the arrangement of fingers and limbs in a way that is very similar to the dinosaurs. Whereas mammals are the organisms that are high and are said that they have evolved the most, and every species classified under mammals has been evolved from the same ancestors, but the species evolved in different ways. The embryo development gives the evidence of the above statement.
References
- http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.530.8703
- https://books.google.co.in/books?hl=en&lr=&id=28TPAAAAMAAJ&oi=fnd&pg=PR7&dq=mammals&ots=y5UD_aexiU&sig=OzSGq6ifohF4OpumCr4UiGzWqik