The Characteristics of Phylum Cnidaria

Characteristics of Phylum Cnidaria n n radial symmetry n n blind sac gut ( = coelenteron or gastrovascular cavity ) n n diploblastic with mesoglea n n polyp and medusa body forms n n nematocysts ( = specialized stinging capsules ) n n nerve net n n lack excretory, circulatory & respiratory systems n n complex life cycle n n many colonial forms exhibiting polymorphism n n radial symmetry n n blind sac gut ( = coelenteron or gastrovascular cavity ) n n diploblastic with mesoglea n n polyp and medusa body forms n n nematocysts ( = specialized stinging capsules ) n n nerve net n n lack excretory, circulatory & respiratory systems n n complex life cycle n n many colonial forms exhibiting polymorphism

Radial Symmetry aboral oral

Radial Symmetry Jellyfish Phylum Cnidaria

Characteristics of Phylum Cnidaria radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism

Blind Sac Gut

Characteristics of Phylum Cnidaria radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism

Diploblastic- two germ layers Phylum Cnidaria

Characteristics of Phylum Cnidaria radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism

Nematocysts

Nematocyst Picture Nematocyst

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Characteristics of Phylum Cnidaria radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism

Nerve Net

Characteristics of Phylum Cnidaria radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism

Diffusion Across the Body Wall

Sea Anemones

Circulation in a Moon Jellyfish

Characteristics of Phylum Cnidaria radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism

The Cnidarian Life Cycle

Characteristics of Phylum Cnidaria radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism radial symmetry blind sac gut ( = coelenteron or gastrovascular cavity ) diploblastic with mesoglea polyp and medusa body forms nematocysts ( = specialized stinging capsules ) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism

Coloniality and Polymorphism

Poly,orphism in the Portuguese Man- of-War

Coloniality Coral Phylum Cnidaria