What are Amphibians?
Life cycle of Frog
- The organisms which show a unique ability to live on land as well as in water are called
amphibians and the subphylum is called Amphibia. For example, frog, salamander, etc.
- Frogs lay their eggs in water. The eggs develop into tadpoles. They swim and live in the surrounding water.
- Once they grow into adult frogs, they come out of the water and start living in terrestrial habitats.
- Some part of their life is mandatorily spent in the water while some on
What are the different systems in amphibians?
Respiratory system of Amphibians
- Frogs and other amphibians have a specialised respiratory On land, they breathe with their lungs, but in water, they carry out gaseous exchange through their skin. Their skin is usually soft, scale-less and moist.
- The digestive system begins at the mouth and ends at the
- The excretory system has a pair of kidneys and the complete urinary
- The nervous system of amphibians has a small brain located in the head region, a spinal cord, and nerves running all over the body which carry
- In amphibians, the sexes are Females are sometimes larger in size compared to males.
Internal systems of Amphibians
- Fertilisation is usually
In frogs, the eggs are released in the water by the female and get fertilised by the floating sperms. The fertilisation results in the formation of small embryos which stick together to form a mass with jelly-like covering. The tadpoles on development get released in water and survive as herbivores. After this stage, Metamorphosis occurs and the tadpole changes into an adult frog.
What are Reptiles?
Reptiles
The air-breathing vertebrates covered in special skin made up of scales, bony plates, or a combination of both, are called reptiles.
For example, crocodiles, turtles, chameleons, snakes, etc.
Reptiles have dry and scaly skin. They are pentadactyl and have five fingers or toes without joints. Some have claws for defence.
Skin of Reptiles
Pentadactyl characteristic of Reptiles
What are the different systems in reptiles?
- Reptiles possess well-developed The digestive system of reptiles shows a proper mouth, oesophagus, stomach, intestines, and anus.
- The excretory system is well-developed and has a pair of kidneys and other organs that helps in eliminating the harmful nitrogenous wastes from their
- The respiratory system shows a pair of lungs which helps in breathing on
Crocodiles spend most of their time underwater. They are capable of holding their breath for quite a long time. They breathe on land and hold their breath underwater.
- Reptiles have a central nervous system consisting of a less developed brain, a spinal cord, and nerves that run throughout their
- Reptiles have separate sexes and they reproduce sexually. The fertilisation in most of them is internal. They are mostly oviparous (egg-laying).
The eggs of reptiles are soft and leathery. All the nutrients required for the growth of the embryo are present in the yolk sac that surrounds the embryo.
