Question

Which of the following is not the character of Taenia solium?

Answer 1

Hint: The segments in a tapeworm are notably different from the segments in the three other groups, namely, Annelida, Arthropoda and Chordata. Segmentation is different from metamerism segmentation. It is mainly limited only to the division of ectodermal-derived tissue as in the class Cestoda.

Complete step by step answer: Taenia solium, commonly known as tapeworm, is a flatworm belonging to the class Cestoda. The body of the tapeworm is divided into many segments known as proglottids. The body has three regions, namely, scolex, the unsegmented neck and strobila (the segmented posterior region). Apolysis is the process of shedding of the gravid proglottids by the tapeworm. This process helps the parasite in the regulation of the length of the body and it also facilitates the transfer of the gravid proglottids inside the intermediate host. The tapeworm belongs to the class Cestoda and family Taeniidae. It is present all over the world and it is more common in the countries where pork is eaten as food. The definitive host in a tapeworm is human and often pigs as an intermediate or secondary host. The class Cestoda shows pseudometamerism. Taenia solium comprises numerous repeating segments. The function of these segments is reproduction and nutrient exchange. Every segment of the tapeworm behaves independently. Hence, this type of segmentation is not considered as true metamerism.
So, the correct answer is option C.

Additional information: Taenia solium has an indirect life cycle. Its life cycle begins with an intermediate host that can be pigs or other animals and then moves to a definitive host that are humans. The infection can be either short or long-lasting in humans. In long-lasting cases, the worm moves into the brain and the infection lasts for life.

Note: Metamerism can be divided into two major categories: 1) Homonymous Metamery: This category includes organisms with a firm and sequential series of metameres. Homonymous Metamery can be further divided into two categories i.e. pseudometamerism (in tapeworm) and true metamerism (in earthworm). 2) Heteronomous Metamery: This category includes organisms where the metameres are assembled together to carry out similar functions. A suitable example of Heteronomous Metamery is an insect head consists of 5 metameres, thorax consists of 3 metameres, and abdomen consists of 11 metameres.