Animal Classification

Classification is a system of arrangement of organisms into different groups on the basis of their similarities, differences and relationship. Classification is also known as TAXONOMY. It is the branch of science which deals with and is defined as Identification, nomenclature and classification of organisms with certain principles. It makes the study of wide variety of organism easy. It also helps to understand the interrelationship among different organisms.

Since the time when Adam named all the animals, people have enjoyed observing the design and variety in God's living creations all around the world. Many people worked on discovering and organizing new plants and animals, but the 1700s, Carolus Linnaeus finally came out with a simple. practical method of classifying the plants and animals into groups according to their similarities. He gave the first basis of modern classification. He divided organisms into 2 kingdoms :
1. Plant Kingdom, and
2.Animal kingdom (because he could see only these).

Carl Linnaeus (Carl von Linné)

Linnaeus divide the classsification from:
1. KINGDOM [largest]
2. PHYLLUM/DIVISION,
3. CLASS,
4. ORDER,
5. FAMILY,
6. GENUS, and
7. SPECIES [smallest].

Ernst Haeckel , a german zoologist , further added one more kingdom PROTISTA which included all unicellular organisms. Robert Whittaker , as more developments in biological sciences happened, found that there were significant differences among organisms of the protista and hence he defined two more kingdoms MONERA , FUNGI. • Thus the 5 kingdom classification by R.H. Whittaker came into existence, which is still the basis of modern classification.

Whittaker classification on 4 factors namely :
1.Cellular structure- whether the organism is Prokaryotic or Eukaryotic.
2.Cellular organization- whether the organism is Unicellular or Multicellular. In multicellular organisms what is the level of organization.
3.Mode of source of nutrition- whether the organism is Autotrophic or Heterotrophic.
4.Phylogenetic relationships- phylogeny means evolutionary history of a species.