Parasitism: (Fig. 5.20)
A relationship in which one organism, known as the parasite, lives in or on another organism, known as host, from which it derives nourishment.
Parasites, usually much smaller than the host, harm the host and gradually kills the host.
o Ectoparasites: live on the surface of their hosts. Ex. Fleas, lice, etc.
o Endoparasites: live inside the bodies of their hosts. Ex. Tapeworm.