Ecology & Environment Test 2

Answer – c

The percentage of carbon dioxide in our atmosphere is a mere fraction of a percent because carbon dioxide is ‘fixed’ in two ways: (i) Green plants convert carbon dioxide into glucose in the presence of Sunlight and (ii) many marine animals use carbonates dissolved in sea-water to make their shells.

Answer – a

• Bio-gas is an excellent fuel as it contains up to 75% methane. It burns without smoke, leaves no residue like ash in wood, charcoal and coal burning. Its heating capacity is high
• The plant has a dome-like structure built with bricks. A slurry of cow-dung and water is made in the mixing tank from where it is fed into the digester. The digester is a sealed chamber in which there is no oxygen. Anaerobic micro-organisms that do not
  require oxygen decompose or break down complex compounds of the cow-dung slurry. It takes a few days for the decomposition process to be complete and generate gases like methane, carbon dioxide, hydrogen and hydrogen sulphide. The bio-gas is stored in the gas tank above the digester from which they are drawn through pipes for use.

Answer – c

• The largest wind energy farm has been established near Kanyakumari in Tamil Nadu and it generates 380 MW of electricity.
• The wind speed should also be higher than 15 km/h to maintain the required speed of the turbine.
• Furthermore, there should be some back-up facilities (like storage cells) to take care of the energy needs during a period when there is no wind.

Answer – c

• The green plants in a terrestrial ecosystem capture about 1% of the energy of sunlight that falls on their leaves and convert it into food energy.
• When green plants are eaten by primary consumers, a great deal of energy is lost as heat to the environment, some amount goes into digestion and in doing work and the rest goes towards growth and reproduction. An average of 10% of the food eaten is turned into its own body and made available for the next level of consumers.
• As the chemicals are not degradable, these get accumulated progressively at each trophic level. As human beings occupy the top level in any food chain, the maximum concentration of these chemicals get accumulated in our bodies. This phenomenon is known as biological magnification.

Answer – a

Answer – c

• Jangalmahal is a district formed by British possessions and some independent chiefdoms lying between Birbhum, Bankura, Midnapore and the hilly country of Chota Nagpur in what is now the Indian state of West Bengal.
• The district is a thickly forested region inhabited by tribal groups such as the Santhal people.
• Koteswara Rao, better known as Kishanji, killed in 2011, was the most-talked-about figure in West Bengal. He was the media-savvy gun-toting guerilla; the face of the deadly Maoist movement in West Bengal in which hundreds of civilians were killed; the terror of the Jangalmahal (the contiguous forested area of the three districts of Bankura, Pashchim Medinipur and Purulia); the self-styled liberator of the oppressed who soon turned into an oppressor himself.

Answer – a

States such as Uttar Pradesh (2.4 %), Rajasthan (2.8 %), Jharkhand (2.7 %), West Bengal (3.2 %), Bihar (3.4 %), Madhya Pradesh (3.5 %), Tamil Nadu (4.1 %), which have contributed less than the national average to the network of projected area, may be requested to achieve the average national target of at least 5% of their geographical area under the four protected area categories

Answer – b

1. Aichi targets are a series of goals that were set in 2010 at a Conference of Parties to the Convention on Biological Diversity meeting for protection and conservation of biodiversity. By 2020, at least 17% of terrestrial & inland water, and 10% of coastal & marine areas, are conserved through systems of protected areas and other effective area-based conservation measures.
2. At present protected areas are 729 in number & cover 4.9% or 162,072 sq. km of India’s geographical area. About 0.3% of EEZ (exclusive economic zone) is under Marine Protected Areas (MPA) in India

Answer – b

Answer – a

Answer – a

• Non-biodegradable wastes are generated by thermal power plants which produce fly
  ash; integrated iron and steel plants which produce blast furnace slag and steel melting slag. Industries manufacturing aluminium, zinc and copper produce mud and tailings. Fertilizer industries produce gypsum. Nowadays, fly ash and slag from the steel industry are utilised by the cement industry.
• Fuel obtained from plastic waste has high octane rating. It contains no lead and is known as “green fuel”.

Answer – d

• Tropical Rain Forests – mahogany, ebony and rosewood
• Tropical Deciduous Forests – sal, teak, peepal, neem and shisham
• Thorny Bushes – Cactus, khair, babool, keekar
• Mountain Vegetation – Chir, Pine and Deodar

Answer – a

• Khadins, tanks and nadis in Rajasthan, bandharas and tals in Maharashtra, bundhis in Madhya Pradesh and Uttar Pradesh, ahars and pynes in Bihar, kulhs in Himachal Pradesh, ponds in the Kandi belt of Jammu region, and eris (tanks) in Tamil Nadu, surangams in Kerala, and kattas in Karnataka are some of the ancient water harvesting, including water conveyance, structures still in use today
• Parts of Himachal Pradesh had evolved a local system of canal irrigation called kulhs over four hundred years ago. The water flowing in the streams was diverted into man-made channels which took this water to numerous villages down the hillside. The management of the water flowing in these kulhs was by common agreement among all the villages. Interestingly, during the planting season, water was first used by the village farthest away from the source of the kulh, then by villages progressively higher up. These kulhs were managed by two or three people who were paid by the villagers. In addition to irrigation, water from these kulhs also percolated into the soil and fed springs at various points. After the kulhs were taken over by the Irrigation Department, most of them became defunct and there is no amicable sharing of water as before.

Answer – a

• 10% can be taken as the average value for the amount of organic matter that is present at each step and reaches the next level of consumers.
• Since so little energy is available for the next level of consumers, food chains
  generally consist of only three or four steps. The loss of energy at each step is
  so great that very little usable energy remains after four trophic levels
• The lesser number of carnivores is a corollary of the reason, not a reason in itself

Answer – b

• The water at the surface of the sea or ocean is heated by the Sun while the water in deeper sections is relatively cold. This difference in temperature is exploited to obtain energy in ocean-thermal-energy conversion plants. These plants can operate if the temperature difference between the water at the surface and water at depths up to 2 km is 293 K (20°C) or more. The warm surface-water is used to boil a volatile liquid like ammonia. The vapours of the liquid are then used to run the turbine of generator. The cold water from the depth of the ocean is pumped up and condense vapour again to liquid.
• Due to geological changes, molten rocks formed in the deeper hot regions of earth’s crust are pushed upward and trapped in certain regions called ‘hot spots’. When underground water comes in contact with the hot spot, steam is generated. Sometimes hot water from that region finds outlets at the surface. Such outlets are known as hot springs. The steam trapped in rocks is routed through a pipe to a turbine and used to generate electricity. The cost of production would not be much, but there are very few commercially viable sites where such energy can be exploited. There are number of power plants based on geothermal energy operational in New Zealand and United States of America .

Answer – b

• More than 70 per cent of all the species recorded are animals, while plants (including algae, fungi, bryophytes, gymnosperms and angiosperms) comprise no more than 22 per cent of the total.
• Among animals, insects are the most species-rich taxonomic group, making up more than 70 per cent of the total.
• The number of fungi species in the world is more than the combined total of the species of fishes, amphibians, reptiles and mammals.
• It should be noted that these estimates do not give any figures for prokaryotes. Biologists are not sure about how many prokaryotic species there might be. The problem is that conventional taxonomic methods are not suitable for identifying microbial species and many species are simply not culturable under laboratory conditions

Answer – c

• German naturalist and geographer Alexander von Humboldt observed that within a region species richness increased with increasing explored area, but only up to a limit.
• On a logarithmic scale, the relationship is a straight line described by the equation log S = log C + Z log A where
  S= Species richness, A= Area, Z = slope of the line (regression coefficient)
  C = Y-intercept

• Ecologists have discovered that the value of Z lies in the range of 0.1 to 0.2, regardless of the taxonomic group or the region (whether it is the plants in Britain,
  birds in California or molluscs in New York state, the slopes of the regression line are amazingly similar).
• But the species-area relationships among very large areas like the entire continents, the slope of the line to be much steeper (Z values in the range of 0.6 to 1.2).

Answer – a

• Catalytic converters, having expensive metals namely platinum-palladium and rhodium as the catalysts, are fitted into automobiles for reducing emission of poisonous gases.
• As the exhaust passes through the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water, and carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas, respectively.
• Motor vehicles equipped with catalytic converter should use unleaded petrol because lead in the petrol inactivates the catalyst

Answer – b

• Eutrophication is the natural aging of a lake by biological enrichment of its water. In a young lake the water is cold and clear, supporting little life.
• With time, streams draining into the lake introduce nutrients such as nitrogen and phosphorus, which encourage the growth of aquatic organisms. As the lake’s fertility increases, plant and animal life burgeons, and organic remains begin to be deposited on the lake bottom. Over the centuries, as silt and organic debris pile up, the lake grows shallower and warmer, with warm-water organisms supplanting those that thrive in a cold environment. Marsh plants take root in the shallows and begin to fill in the original lake basin.
• Eventually, the lake gives way to large masses of floating plants (bog), finally converting into land.

Answer – a