Cnidaria
-The Cnidaria phylum is made up of over 10,000 species, all of which live in marine environments.
-The organisms have an epidermis (outer cell layer), a gastrodermis (inner cell layer), and a mesoglea (non cellular layer) in between.
-The organisms have 2 adult forms in their life cycle: Polyp and Medusa
-They have up to a tissue level of organization
- Three organisms in this phylum are: jelly fish, sea anemones, and hydras
-The organisms have an epidermis (outer cell layer), a gastrodermis (inner cell layer), and a mesoglea (non cellular layer) in between.
-The organisms have 2 adult forms in their life cycle: Polyp and Medusa
-They have up to a tissue level of organization
- Three organisms in this phylum are: jelly fish, sea anemones, and hydras
Jelly Fish
Jelly fish do not have a specialized respiratory system. Their surface is thin enough for the jellyfish to take oxygen directly from the water and then release carbon dioxide. The oxygen is absorbed through the coelenteron. Therefore, jellyfish take in oxygen and release carbon dioxide through diffusion because of their thin layer of skin.
Sea Anemones
Similar to the jellyfish, a sea anenome does not have a complex respiratory systems and it does not have organs that make up a system. On the sea anenome, a pore takes in a flow of water that carries the oxygen. The oxygen is then absorbed into the sea anenome, and the flow of water removes waste such as carbon dioxide. Without lungs and gills, the sea anenome must go through passive diffusion to absorb oxygen.
Hydras
Being in the Cnidaria phylum, hydras also breathe by going through passive difussion, just like the jelly fish and sea anenomes. The epidermis, which surrounds the hydra, is able to take in the oxygen from the water. The waste, carbon dioxide, is then released in the same way through the epidermis. Having a thin epidermis and lacking a respiratory system allows hydras and other organisms in this phylum to breathe using passive difussion.