While living in and on the host species, the animal parasite has evolved certain adaptations. Describe these adaptations with examples.

Explanation

Parasites , especially endoparasites , generally occupy the well protected organs of the host with abundant supply of nutrients, so show following types of adaptatios:
(a) Intestinal parasites are generally covered by a cuticel to resist their digestion e.g. Ascaris, Taenia etc.
(b) Endoparasites are generally anaerobic in respiration.
(c) Some adhesive structures are developed to avoid their expulsion out of body e.g. hooks in Ancystoma, suckers in Taenia, etc.
(d) Loss of organs of locamotion as are well supplied with nutrients e.g. Absence of jointed appendagnes in Sacculina (a crustacean).
(e) High rate of reproduction to compensate inevitable loss during their transfer from one host to another.
(f) Simplified sense organs and nervous system e.g. only certain papillae present in Ascaris.