CLASSIFICATION OF ORGANISM
Classifying organisms is called Taxonomy Habitat - Most of the animals inhabit seas,
(Taxis means arrangement and nomos fewer are seen in fresh water and even
means method) fewer on land.
The modern taxonomic system was There are around 9 to 10 million animal
developed by the Swedish botanist species that inhabit the earth. Only
Carolus (Carl) Linneaeus (1707-1788). He 800,000 species are identified.
used simple physical characteristics of
organisms to identify and differentiate Some important groups are listed below.
between different species, and is based Phylum Porifera - They are primitive
organisms, most of them are salt-water
He developed a hierarchy of groups for sponges. They do not have organs or nerve
taxonomy. cells or muscle cells. Approximately, 8,000
These groups are known as taxa (singular: species exist today. e.g. Sycon, Euspongia,
It is in hierarchical order: Phylum Coelentrata (Cnidaria) - This group
is composed of jelly-fish and other lower
aquatic animals. Approximately, 15,000
species exist today. e.g. Aurelia, Adamsia.
4. Order Phylum Platyhelminthes - This group
5. Family consists of flat worms. They inhabit both
6. Genus marine and fresh water habitats and they are
7. Species mostly endoparasites found in animals. e.g.
Phylum Aschelmeinthes - It is a group of
All organisms are divided into five Kingdoms:
round worms, most of them are parasites. This
1. Animal Kingdom (Animalia) phylum consists of about 80,000 parasitic
2. Plant Kingdom (Plantae) worms.
3. Fungi Kingdom (Fungi)
Phylum Annelida - They are present in
4. Protist Kingdom (Protista)
aquatic, terrestrial and are free-living or
5. Moneran Kingdom (Monera)
parasitic in nature. This phylum comprises of
Animal Kingdom (Animalia or Metazoa) segmented worms. e.g. Earthworm, Leech etc.
The word "animal" is derived from the Phylum Arthropoda - This is the largest
Latin word animalis which means "having phylum which consists of insects. There are
breath". over 1 million species of insects existing
Animals are eukaryotic, multicellular and today. e.g. Locusts, Butterfly, Scorpion,
heterotrophic organisms. Prawn.
They have multiple cells with
Phylum Mollusca - It is the second largest
mitochondria and they depend on other
phylum. They are terrestrial and aquatic. e.g.
organisms for food.