QUIZ – 2020: INSIGHTS STATIC , 2 December 2020 – Environment

Solution: c)

“Bioluminescent organisms are usually found in the ocean environments, but they are also found on terrestrial environments. The colour of the light emitted by the organism depends on their chemical properties.”

In the case of fungi, the luminescence comes from the enzyme, luciferase. “The [green] light emits when luciferans is catalysed by the enzyme luciferase, in the presence of oxygen. During the chemical reaction, several unstable intermediate products are released as excess energy that makes them visible as light.

Such mushrooms may glow for a number of reasons. The simplest explanation could be that bioluminescence attracts insects, which helps in dispersing spores. It may also be a mechanism for the organism to protect itself from frugivorous (or fruit-eating) animals.

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Solution: d)

Life is found almost everywhere on Earth, but it is not distributed evenly around the planet. Different species are found in different areas; some species have overlapping ranges, others do not. Each species has a set of environmental conditions within which it can best survive and reproduce. Not surprisingly, those conditions are the ones for which it is best adapted. Many different physical, abiotic (non- living) factors influence where species live, including temperature, humidity, soil chemistry, pH, salinity and oxygen levels.

For instance, a giraffe does very well in the heat of the African savanna, but would quickly freeze to death in the Arctic. This example points out an important aspect of tolerance ranges – different types of organisms have different tolerance ranges for the same factor.

Solution: a)

To qualify as a biodiversity hotspot, a region must meet two strict criteria:

• It must have at least 1,500 vascular plants as endemics — which is to say, it must have a high percentage of plant life found nowhere else on the planet. A hotspot, in other words, is irreplaceable.
• It must have 30% or less of its original natural vegetation. In other words, it must be threatened.

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Solution: b)

Many desert plants have a thick cuticle on their leaf surfaces and have their stomata arranged in deep pits (sunken) to minimise water loss through transpiration. They also have a special photosynthetic pathway (CAM) that enables their stomata to remain closed during day time.

in the low atmospheric pressure of high altitudes, the body does not get enough oxygen. The body

compensates low oxygen availability by increasing red blood cell production, decreasing the binding affinity of hemoglobin and by increasing breathing rate.

Solution: a)

Burning of fossil fuels (which contain sulphur and nitrogenous matter) such as coal and oil in power stations and furnaces or petrol and diesel in motor engines produce sulphur dioxide and nitrogen oxides.

SO2 and NO2 after oxidation and reaction with water are major contributors to acid rain, because polluted air usually contains particulate matter that catalyze the oxidation.

These lead to formation of acid rain that has deleterious effect on the overall ecology of the region.