Biotic Interaction — Set 2

Correct Answer: D. Endoparasite

Endoparasites live inside the tissues or organs of their host. Examples include tapeworms and the malarial parasite Plasmodium. They are often highly specialized to evade the host's immune system.

Correct Answer: A. Non-mandatory but beneficial

The correct answer is 'Non-mandatory but beneficial'. In proto-cooperation, both species benefit but can survive easily without each other. The relationship between crocodiles and plover birds is a classic instance. It is considered a facultative or optional form of mutualism.

Correct Answer: D. Fungi and Roots of higher plants

The correct answer is 'Fungi and Roots of higher plants'. The fungus helps the plant absorb nutrients while the plant provides carbohydrates to the fungus. This mutualistic interaction is vital for the growth of many forest trees. It significantly improves a plant's resistance to drought and soil toxins.

Correct Answer: A. Total parasite

Cuscuta is a leafless plant that derives all its nutrients and water from a host plant. It uses specialized structures called haustoria to penetrate the host's vascular system. It is classified as a total stem parasite.

Correct Answer: A. Predation

The correct answer is 'Predation'. The plus sign indicates the predator benefits while the minus sign shows the prey is harmed. This energy transfer is a fundamental part of food chains. Parasitism also shares this same (+, -) symbol set.

Correct Answer: D. Neutralism

Neutralism is a theoretical interaction where two species occupy the same space without interaction. True neutralism is rare in complex ecosystems because all organisms are interconnected. It is mathematically represented by the symbols (0/0).

Correct Answer: A. Mutualism

The correct answer is 'Mutualism'. The bacteria provide nitrogen to the plant while the plant provides energy and shelter. Rhizobium is the most well-known genus of bacteria performing this function. This interaction is a cornerstone of sustainable agriculture.

Correct Answer: D. Commensalism

The correct answer is 'Commensalism'. The host provides resources or space for the commensal species. Orchids growing as epiphytes on mango branches follow this pattern. The orchid gains height for sunlight while the mango tree remains unaffected.

Correct Answer: C. Competition

Competition results in both species expending energy and losing access to resources. This usually leads to the competitive exclusion of the weaker species. It is a major driving force in the evolution of species.

Correct Answer: C. Commensalism

While the clownfish gains protection, the sea anemone is generally considered to be unaffected. However, some scientists argue this is mutualism if the fish cleans the anemone. In standard textbooks, it is frequently cited as commensalism.