Cnidarians have become more complex in terms of organisation than the poriferan as they have developed a tissue level organisation,they show locomotion , exhibit polymorphism and a radial symmetry.
This means that cnidarians evolved later than poriferans and are adapted to more competitive and complex environment.
Explanation:
- Poriferans are pore bearing animals , they have cell specialization but no tissue level organisation while cnidarians are diploblastic and exhibit tissue level organisation.
- Poriferans are asymmetrical organisms hence are primitive to the radially symmetrical cnidarians.
- poriferans obtain nutrition mostly through filter feed while cnidarians have a gastro vascular cavity for digestion.
