Biology

61. Given below is a list of autotrophs and heterotrophs. With your knowledge about the food chain, establish various linkages between the organisms on the principle of ‘eating and being eaten’. What is this inter-linkage established known as? Algae, hydrilla, grasshopper, rat, squirrel, crow, maize plant, deer, rabbit, lizard, wolf, snake, peacock, phytoplankton, crustaceans, whale, tiger, lion, sparrow, duck, crane, cockroach, spider, toad, fish, leopard, elephant, goat, Nymphaea, Spirogyra.

Solution - t his linkage established is known as a food web . Primary Producer’s (Tropic level I): Algae, Hydrilla, a maize plant, Phytoplankton, Nymphaea, and Spirogyra. Primary Consumer (Tropic...

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57. In an aquarium, two herbivorous species of fish are living together and feeding on phytoplankton. As per the Gause’s Principle, one of the species is to be eliminated in due course of time, but both are surviving well in the aquarium. Give possible reasons.

Solution - According to Gause’s principle , no two species can live in the same niche and hence one of them need to be eliminated . But in the given condition two herbivorous species are living...

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43. Lianas are vascular plants rooted in the ground and maintain erectness of their stem by making use of other trees for support. They do not maintain a direct relationship with those trees. Discuss the type of association the lianas have with the trees.

Solution - The association in which one is Lianas and other is trees is commensalism . In such type of association  one species is benefitted and the other is neither benefitted nor harmed . The...

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6. Drugs like LSD, barbiturates, amphetamines, etc., are used as medicines to help patients with mental illness. However, excessive doses and abusive usage are harmful. Enumerate the major adverse effects of such drugs in humans.

Solution; Drugs are chemical molecules that have psychological and physiological impacts on your body, however overdosing can have the following negative consequences: 1. When taken in excess, it...

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20. A person shows strong unusual hypersensitive reactions when exposed to certain substances present in the air. Identify the condition. Name the cells responsible for such reactions. What precaution should be taken to avoid such reactions?

Solution: This uncommon hypersensitive reaction is an allergy that develops as a result of being exposed to allergens. Such reactions are caused by mast cells. This can be avoided by taking...

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8. Gene flow occurs through generations. Gene flow can occur across language barriers in humans. If we have a technique of measuring specific allele frequencies in a different population of the world, can we not predict human migratory patterns in pre-history and history? Do you agree or disagree? Explain your answer.

Solution: Yes, there is intergenerational gene flow. We can forecast human migratory patterns in prehistory and history by researching certain gene frequencies in different populations around the...

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1. Louis Pasteur’s experiments, if you recall, proved that life can arise from only pre-existing life. Can we correct this as life evolves from pre-existent life or otherwise we will never answer the question as to how the first forms of life arose? Comment.

Solution: So we can rectify Louis Pasteur's assertion, Oparin of Russia and Haldane of England hypothesised that the first form of life could have emerged from pre-existing non-living organic...

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