Protostomes And Deuterostomes

Protostomes And Deuterostomes

1. Protostomes – In protostomes mouth develops from blastopore. E.g. Annelida, Arthropoda, Mollusca.

2. Deuterostomes – The mouth never develops from the blastopore, although the blastopore may give rise to the anus. E.g. Echinoderms and Chordata.

Table: Non-chordates And Chordates

Non-chordates Chordates

1. Radially, bilaterally symmetrical Bilaterally symmetrical or Asymmetrical

2. Diploblastic or Triploblastic Triploblastic

3. Acoelomate, Pseudocoelomate or Eucoelomate Eucoelomate

4. Notochord – absent Notochord – present

5. Pharyngeal gill-slits – absent Pharyngeal gill-slits present at some stage of life.

6. Ventral nerve cord – present Dorsal tubular nervous system present

Fig. Generalised invertebrate organisation (diagrammatic)

Fig. Generalised vertebrate organisation (diagrammatic)