Animal Kingdom – Notes

Basis of Animal Classification
Animals are classified on the basis fundamental features such as level of organisation, symmetry, cell organisation, nature of coelom, segmentation and notochord.
Level of organisation is the first basic fundamental feature by which animals are classified. There are four main types of cell patterns: cellular, tissue, organ and organ system.
Some animals are symmetrical, some have radial symmetry and many exhibit bilateral symmetry.
In animals, there are two types of cell organisation-diploblastic and triploblastic.
Acoording to the nature of coelom, animals are classified as coelomates, acoelomates and pseudocoelomates.
Animals are also classified on the basis of segmentation.
The most important feature for animal classification is the presence or absence of a notochord.

Non-chordates I
Animals belonging from Phylum Porifera to Echinodermata are categorised as non-chordates.
Non-chordates are animals without a notochord.