Question

How animals are classified based on the presence of notochord?

Answer 1

The notochord is a long rod-like support structure formed on the dorsal side of the animal that runs along the back of the animal separating the nervous tissue from the gut.

Based on the presence of the notochord, the animals can be divided into two types i.e., chordates and non-chordates.
(i) Chordates - Chordates are animals characterized by the presence of notochord.

1. All Chordates have paired gill pouches.
2. All Chordates are triploblastic.
3. All Chordates have a notochord.
4. All Chordates have a dorsal nerve cord.
5. Example: - Reptiles and mammals

(ii) Non-chordates-

1. Non-chordates are animals without a notochord.
2. It consists of a small group of worm-like, marine species with an organ-system level of organization.
3. Example: - Porifera and echinoderms.