(a) Write how parasites have evolved with adaptation to coexist 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 ?

Assertion : Virus is an obligate parasite. Reason : Virus is host specific.

Many parasites have evolved to be …….A……in such a way that both host and the parasite tend to ……….B…….that is if host evolves special mechanisms for rejecting or resisting the parasists the parasite have to evelve mechanisms to ……..C…… and neutralise them , in order to be successful with the same host species Choose the correct option for A ,B and C

Explain co-evolution with reference to parasites and their hosts. Mention any four special adaptive features evolved in parasites for their parasitic· mode of life.

Read the following statements and find out the incorrect statement(s). a. Parasatic mode of life ensures free lodging and meals so parasitism has evolved in so many taxonomic groups from platns to higher vertebrates/ b. Many parasites have evolved to be host specific, i.e. they can parasitise only a single species of host. c. The life-cycle of parasites are often complex, involving one or two intermediate host or vectors to facilitate parasitisation of its secondary host. d. All parasites harm the host. e. Lice on dogs and ticks on humans are familiar examples of ectoparasites.

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

List any two adaptive features evolved in parasites enabling them to live successfully on their hosts .

Read the following statements and select the correct option. Statement 1: Brood parasitism in birds is an example of parasitism in which the parasitic bird lays its eggs in the nest of its host and the host incubates them. Statement : During the course of evolution, the eggs of the parasite bird have evolved to resemble the host's eggs in size and colour to reduce the chances of the host bird detecting the foreign eggs and removing them from the nest.