POLL WITH ANSWERS WITH EXPLANATION 27.7.2020

1.) Consider the following statements with regard to Biosphere –

i. Biosphere includes both biotic and abiotic components that are present in the lithosphere, hydrosphere and the atmosphere.
ii. In a biosphere there are established pathways for movement of energy and matter.

Which of the above statements are true?

A. i only
B. ii only
C. Both i and ii
D. None of the above.

Ans: C

Biosphere is that part of lithosphere, hydrosphere and atmosphere where plants and animals live. Biosphere contains all life forms on earth. The biosphere consists of – the biotic component and the abiotic component. There are continuous interactions between the living organisms and their physical environment and among the living organisms themselves via established pathways for movement of energy and matter.

2.) Match the following –

i. Earthworm a. Scavenger
ii. Vulture b. Decomposer
iii. Fungi c. Detrivore

i. ii. iii.

A. c a b
B. a b c
C. a c b
D. c b a

Ans: A

Detritivores directly feed on small quantities of dead plant and animal material (millipedes, earthworms, sea cucumbers etc.). Decomposers, such as bacteria and fungi promote decay of organic matter through enzymatic action. Scavengers are typically not thought to be detritivores, as they directly consume large quantities of dead organic matter.

3.) In an ecosystem, a flowering plant is being consumed by a caterpillar which in turn is eaten by a frog. The frog is preyed upon by a snake which in turn is consumed by a higher predator such as an eagle. What type of a food chain does this feeding pattern represent?

A. Detritus food chain
B. Grazing food chain
C. Omnivorous food chain
D. None of the above

Ans: B

In a grazing food-chain, the first level starts with plants as producers and ends with carnivores as consumers at the last level, with the herbivores being at the intermediate level.

4.) Which of the following functions of a black bear can be categorized as its ecological niche?

i. Feeds on nuts, fruits, insects and small animals.
ii. Feeds on blood-feeding parasites.
iii. Helps disperse seeds of berries over long distances and helps in propagation.

A. i and ii
B. i and iii
C. iii only
D. i, ii and iii

Ans: D

The role and position that an organism takes in the ecosystem is known as its ecological niche. It includes its consumption pattern, contributions to the ecosystem, dwelling preferences etc.

5.) Which of the following is NOT a Bio-Magnifier?

A. Mercury
B. Cyanide
C. Cadmium
D. Lithium

Ans: D

Following substances have the potential to bio magnify – Polychlorinated Biphenyls, Poly nuclear aromatic hydrocarbons, Heavy metals like Mercury, copper, cadmium, chromium, lead, nickel, zinc, tin (TBT or tributyltin) and Cyanides.

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