Thursday, March 1, 2007

Comparisons to Other Phyla

Cnidarians can be completely different from other invertebrates, but at the same time, they can be quite similar. Below are a few examples.


- Cnidaria and Platyhelminthes expel undigested material through the mouth

- Cnidaria and Planaria both lack specialized circulatory and respiratory systems

- Cnidaria and Platyhelminthes both lack a centralized nervous system


- Platyhelminthes have much more developed nervous systems compared to Cnidarians

- Cnidaria have nematocysts as protection. Other phyla have different methods (ie. Spicules in Porifera

- Nematoda have a complete gut, Cnidarians do not
Above is a picture of a sea anemone and on the right is the ventral side of a octopus. Can you see and similarities or differences?

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