Question

(a) Write how parasites have evolved with adaptation to co-exist with their hosts in an ecosystem.

(b) Parasites are host specific and tend to co-evolve. How would the parasite respond if the host evolves a certain mechanism to resist or reject the parasite? [3 marks]

Answer 1

(a) Parasites have evolved with special adaptations to co-exist with their hosts in an ecosystem in the following ways: [0.5 mark for each point]
i. Loss of unnecessary sense organs
ii.Presence of adhesive organs or suckers to cling on to the host iii. Loss of digestive system and high reproductive capacity.

(b) If the host evolves special mechanisms for rejecting or resisting the parasite, the parasite also evolves mechanisms to counteract and neutralise them, in order to be successful with the same host species. In accordance with their life styles, parasites evolve special adaptations and co-evolve with the host. [1.5 mark]