Animals

 

What is an Animal?

Animals are simply defined as multicellular, eukaryotic, aerobic organisms which feed on plants and other animals as their source of food. All these animals reproduce sexually and live freely in habitat. Altogether, there are two to three millions of animal species and are grouped into the Animal kingdom, which is the largest and most diverse group among the five kingdoms of biological classifications. Based on their similarities, characteristic features, and genetic analysis, animals are grouped into Kingdom Animalia.

In order to study the different types of animals along with their features, taxonomists grouped all animals into Kingdom Animalia, which is further divided into divisions and subdivisions. Based on their body structure and the presence of the backbone, animals are divided into vertebrates and invertebrates. More than millions of invertebrate species are discovered, whereas only fifty to sixty thousand of different vertebrates are identified.

Invertebrates include Flatworms (e.g.: Tapeworms), Annelids (e.g.: Earthworms), Echinoderms (e.g: starfish), Coelentrates (e.g.: jellyfish), Molluscs (e.g.: snails), Arachnids (e.g.: spiders),  Crustaceans (e.g.: Crabs), Insects (e.g.: Ants) and Myriapods (e.g.: centipede). Vertebrates include reptiles (e.g.: Lizard), Aves (e.g.: crow), Fish (e.g.: Tuna), Amphibians (e.g.: Frogs) and Mammals (e.g.: Cow).