Phylum: Nematoda
The Nematode phylum is probably the most hardest to distinguish. The phylum consist with over 28,000 organisms and over 16,000 are known to be parasitic. Almost half of the Nematoda phylum are parasitic. The Nematoda phylum mostly contains of roundworms or
worm-like organisms. They have a digestive, nervous and reproduction systems,
but they lack a circulatory and respiratory. How do they breath? Doesn't the
respiratory play a crucial role for an organism? The Nematoda are similar to
the Cnidaria, in this way. The Nematodes are able to create oxygen through the
surface of their body surface. Nematodes have the ability to give off carbon
dioxide and pick up oxygen molecules from the moist environment. This is only
possible due to their high surface area compare to there small body. Just like
the Cnidaria they are able to use their structure in a moist environment to
make up for their lungs.
Roundworms
Roundworms are very flexible creatures, they can live in almost any kind of environment. They can live even in our body. The Round worms use a process known as diffusion to breath. In water or in air, they are able to extract the oxygen molecules through this process. This process is possible because there surface is covered with cells that are able to extract and distribute oxygen within its body.
Hookworms
These worms are parasitic organisms. They have the ability to use diffusion and obtain oxygen. When they enter the host's body, they are able to leech of nutrients and even the little oxygen that is flowing within the bloodstreams. They can become anaerobic once they have entered inside the host's body.
Red Stomach Worm
The Red Stomach Worm, also known as the barber's pole worm, is a very common parasite among sheep and goats. In side the host's body they make there way into the host's stomach, where they stay to leech of the host. They share the same basic way of breathing with the other organisms in the Nematoda phylum. They use diffusion to take in amounts of oxygen.