Features of Important Phyla

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Features of Important Phyla

 Cnidaria: Platyhelminth: Nematode: Echinoderm:
Body layers:Diploblastic. Triploblastic. Triploblastic. Triploblastic.
Coelom: No.No.Pseudocoelom.Yes.
Symmetry: Radial.Bilateral.Bilateral. Pentamerous (5 lines).
Segmentation: No. No. No. No.
Lifestyle: Sedentary or free swimming. Free living or parasitic. Free living or parasitic. Free living.
Body form: Polyp and medusa stages (polymorphic). Dorso-ventrally flattened (large surface area : volume ratio). Parasites have a cuticle. Cylindrical tapering at ends. Have a cuticle. Variable.
Gut: Single opening (no separate mouth and anus). Simple central cavity. Tubular with side passages. Single opening. Tubular with mouth and anus. Mouth ventral, anus dorsal. Rasping jaw or eversible stomach!
Feeding: Tentacles around the mouth. Stinging cells (nematocysts) paralyse prey. Predatory, if free living. Absorptive if parasitic. Some have a spike-like tooth to stab prey or a stylet to suck body fluids. Some evert stomach onto prey. Others grind algae off surfaces.
Gas exchange: Diffusion from water over whole body surface. Diffusion through damp body surface. Diffusion through damp body surface. Diffusion.
Circulation None (done by diffusion).None. None.Coelomic fluid. No proper blood.
Asexual reproduction: Budding. Fission. c Regeneration. Bilateral division.
Sexual reproduction Simple gonads.Hermaphrodite. Sometimes hermaphrodite. Mainly separate sexes in separate individuals. Hermaphrodite.
Example of species: Hydra oligactis (brown hydra). Class = Hydrozoa. Fasciola hepatica (sheep liver fluke). Class = Trematoda. Ascaris lumbricoides (parasitic roundworm). Class = Ascaridae. Oreasta reticulatus (starfish). Class = Asteroidea.


Part 2
  Annelid: Mollusc: Arthropod:Chordate:
Body layers: Diploblastic. Triploblastic. Triploblastic. Triploblastic.
Coelom: No. No. Pseudocoelom. Yes.
Symmetry: Radial. Bilateral. Bilateral. Pentamerous (5 lines).
Segmentation: No. No. No. No.
Lifestyle: Sedentary or free swimming. Free living or parasitic.Free living or parasitic. Free living.
Body form: Polyp and medusa stages (polymorphic). Dorso-ventrally flattened (large surface area : volume ratio). Parasites have a cuticle. Cylindrical tapering at ends. Have a cuticle. Variable.
Gut: Single opening (no separate mouth and anus). Simple central cavity. Tubular with side passages. Single opening.Tubular with mouth and anus. Mouth ventral, anus dorsal. Rasping jaw or eversible stomach!
Feeding: Tentacles around the mouth. Stinging cells (nematocysts) paralyse prey. Predatory, if free living. Absorptive if parasitic. Some have a spike-like tooth to stab prey or a stylet to suck body fluids. Some evert stomach onto prey. Others grind algae off surfaces.
Gas exchange: Diffusion from water over whole body surface. Diffusion through damp body surface. Diffusion through damp body surface. Diffusion.
Circulation None (done by diffusion). None. None. Coelomic fluid. No proper blood.
Asexual reproduction: Budding.Fission. c Regeneration. Bilateral division.
Sexual reproductionSimple gonads.Hermaphrodite. Sometimes hermaphrodite. Mainly separate sexes in separate individuals. Hermaphrodite.
Example of species: Hydra oligactis (brown hydra). Class = Hydrozoa. Fasciola hepatica (sheep liver fluke). Class = Trematoda. Ascaris lumbricoides (parasitic roundworm). Class = Ascaridae. Oreasta reticulatus (starfish). Class = Asteroidea.
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