Classification Decision Flowchart
Vertebrate Heart Chamber Progression
Starfish (Echinodermata) — Water Vascular System
Image: Starfish (Asterias) showing pentamerous radial symmetry and tube feet. Source: Wikimedia Commons, public domain.
Phylum vs Coelom Type — Summary Table
| Coelom Type | Phylum | Key Feature |
|---|---|---|
| No true coelom (acoelomate) | Platyhelminthes | Flame cells, dorso-ventrally flat |
| Pseudocoelom | Aschelminthes | Complete gut (mouth to anus) |
| True coelom (coelomate) | Annelida | Metameric segmentation, nephridia |
| True coelom (coelomate) | Arthropoda | Chitinous exoskeleton, Malpighian tubules |
| True coelom (coelomate) | Mollusca | Mantle, radula; Cephalopoda = closed circulation |
| True coelom (coelomate) | Echinodermata | Water vascular system, tube feet |
| True coelom (coelomate) | Chordata | Notochord → vertebral column |
Unique Identifying Features — Quick Visual Reference
| Phylum | Unique Structure | Function |
|---|---|---|
| Porifera | Choanocytes (collar cells) | Filter feeding via flagellar currents |
| Cnidaria | Cnidocytes / Nematocysts | Prey capture and defence |
| Ctenophora | Comb plates (ctenes) | Locomotion; bioluminescence |
| Platyhelminthes | Flame cells | Excretion and osmoregulation |
| Aschelminthes | Pseudocoelom | Hydrostatic skeleton |
| Annelida | Nephridia + Setae | Excretion; locomotion |
| Arthropoda | Chitinous exoskeleton + Jointed appendages | Protection; movement |
| Mollusca | Mantle + Radula | Shell secretion; feeding |
| Echinodermata | Water vascular system | Locomotion, feeding, respiration |
| Hemichordata | Stomochord | Feeding (not homologous to notochord) |