One of the most fascinating Biology Topics is the study of the brain and behavior.
Introduction to the Nematoda
1. Bilaterally symmetrical, triploblastic, pseudocoelomate, and unsegmented animals.
2. Body is worm-like (i.e., round, slender, and tapering at the two ends), cylindrical or flattened.
3. Body is covered with a tough, resistant cuticle; cilia are absent.
4. Alimentary canal straight and complete with mouth and anus; pharynx muscular.
5. Sexes are separate.
6. Most forms are parasitic but some are free-living in soil or water.
7. Parasitic nematodes are pathogenic, meaning they Male Ascaris Female Ascaris MaieAncylostoma produce diseases in the hosts.
For example, elephantiasis in which enlargement of limbs, scrotum, and mammae of humans takes place due to infection of Wuchereria bancrofti. This disease spreads through mosquito bites. Likewise, Ascaris and Enterobius live in the human intestine and cause ascariasis and enterobiasis respectively in humans.
Examples: Ascaris (roundworm), Ancylostoma (hookworm), Wuchereria bancrofti (filarial worm), and Enterobius (pinworm of human).
Differences between Platyhelminthes and Nemathelminthes (=Nematoda)
| Platyhelminthes | Nemathelminthes |
| 1. They are flatworms. | 1. They are cylindrical in form and are called roundworms. |
| 2. They are acoelomate. | 2. They are pseudo coelomate. |
| 3. They have an incomplete digestive system. | 3. They have a complete digestive system. |
| 4. They are hermaphrodites (i.e., an individual has both types of sex organs). | 4. They are unisexual (i.e., males and females are present). |
| 5. Examples: Liver fluke, pork tape-worm. | 5. Examples: Ascaris |