Q. Researchers simulated street lighting on artificial grassland plots contaaining pea-aphids, sap-sucking insects, at night.
These were exposed to two different types of light – a white light similar to newer commercial LED lights and an amber light similar to sodium street lamps. The low intensity amber light was shown to inhibit, rather than induce, flowering in a wild plant of the pea family which is a source of food for the pea-aphids in grasslands. The number of aphids was also significantly suppressed under the light treatment due to the limited amount of food available.
Q 1. Which one of the following statements best reflects the most critical inference that can be made from the passage given above?
(a) Low intensity light has more adverse effect on the plants as compared to high intensity light.
(b) Light pollution can have a permanent adverse impact on an ecosystem.
(c) White light is better for the flowering of plants as compare to the light of other colours.
(d) Proper intensity of light in an ecosystem is important not only for plants but for animals too.
Question from UPSC Prelims 2021 CSAT Paper
Explanation :
Q1: Correct Answer – (b) Light pollution can have a permanent adverse impact on an ecosystem.
Explanation – The most critical inference that can be made from the passage given above is that light pollution can have a permanent adverse impact on an ecosystem. This is because the low intensity amber light was shown to inhibit flowering in a wild plant of the pea family which is a source of food for the pea-aphids in grasslands. The number of aphids was also significantly suppressed under the light treatment due to the limited amount of food available. This shows that light pollution can have a cascading effect on an ecosystem.
So, option (b) “Light pollution can have a permanent adverse impact on an ecosystem” best reflects the most critical inference that can be made from the passage given above.
