Grade 2 | Science | Animals classification, Animals, Olympiad, CBSE, ICSE, SOF, ITO
1. Terrestrial Animals:
Animals which live on land are called terrestrial animals. They generally have four legs. Terrestrial animals have well-developed sense organs. E.g. Tiger, Lion, Elephant, Dogs, Cat etc.
2. Aquatic Animals:
Animals which live in water are called aquatic animals. Many aquatic animals like fishes have special respiratory organs called gills. Gills consists of membranes and are connected with blood vessels. Gills extract dissolved oxygen from water and excrete carbon dioxide.
3. Aerial Animals:
Animals which spend most of their time in the air are called aerial animals. Birds come under this category.
4. Arboreal Animals:
Arboreal animals live on trees. E.g. monkeys, lizards, squirrel, chameleon etc.
Amphibians can live in water as well as land. Amphibians are cold-blooded. Amphibians don't have scaly skin. Their skin is slimy and permeable that means air and water can pass through it.Some amphibians have gills at the beginning of their life. Some examples of amphibians are frogs, toads, salamanders and caecilians.
Animals which eat only plants and grass are called herbivorous. They generally have flat, broad teeth. As they eat plants only they are called primary consumers. E.g. cow, deer etc
Animals which eat other animals are called carnivorous. They have sharp, pointed teeth to tear the flesh of their preys. E.g. tiger, snakes etc
Animals which eat plants, as well as other animals are called omnivorous. E.g. Dog, Beer etc.
Animals which have backbones are called vertebrates.
Mammals, birds, fish, reptiles, amphibians are vertebrates. They have backbones. Insects and worms are not vertebrates.
Animals which lay eggs are called oviparous. Birds are oviparous. Penguin is oviparous. Bats are not oviparous. Bats are mammals.
Following are the characteristics of reptiles :
1) Reptiles are vertebrates, that means they have a backbone.
2) Reptiles have scaly skin.
3) Most reptiles lay eggs except for boa constrictor. Boa gives birth to young ones.
4) Reptiles are cold-blooded.
5) Reptiles breathe with lungs.
6) Most reptiles are four-legged except for snakes.
E.g. of reptiles: snakes, turtles, crocodiles, lizards, tuatara, chameleon etc.