Parasites have evolved special adaptations to their way of life. Consider the following statements:
A. Parasites show loss of unnecessary sense organs.
B. Parasites have adhesive organs or suckers to cling on to the host.
C. Parasites have a low reproductive capacity.
D. Many parasites show loss of the digestive system.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A, B and D only
A parasite lives on or in a host and depends on it for food and shelter. The host does the work of finding food, so many structures become useless to the parasite and are lost. At the same time the parasite needs ways to hold on to the host and to reach new hosts.
A. Parasites show loss of unnecessary sense organs. — True. A parasite living on its host has little use for many sense organs, so they are lost.
B. Parasites have adhesive organs or suckers to cling on to the host. — True. Adhesive organs or suckers keep the parasite attached to its host.
C. Parasites have a low reproductive capacity. — False. Parasites show a high reproductive capacity. Their life cycles are often complex, and many offspring improve the chance that some reach a new host.
D. Many parasites show loss of the digestive system. — True. Many parasites take in food already digested by the host, so they show loss of the digestive system.
NCERT Extract:
Population Interactions – “… In accordance with their life styles, parasites evolved special adaptations such as the loss of unnecessary sense organs, presence of adhesive organs or suckers to cling on to the host, loss of digestive system and high reproductive capacity. The life cycles of parasites are often complex, involving one or two intermediate hosts or vectors to facilitate parasitisation of its primary host.”