Intense Revision Plan By Civils360 Day 1 Ecology

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1 Intense Revision Plan By Civils360 Day 1 Ecology 1. Consider the statements regarding Habitat and Environment? 1. A habitat always has life in it, whereas the environment does not necessarily have life in it. 2. A habitat is always a preference of one species, 3. Habitat refers to the unique functional role and position of a species in its ecosystem. (b) 1 and 3 (c) 2 and 3 Ans A : Ecological Niche refers to the unique functional role and position of a species in its habitat or ecosystem. A habitat always has life in it, whereas the environment does not necessarily have life in it. The habitat is a defined place or area of the environment according to the requirements of a particular life form. Therefore, a habitat is always an environment, but an environment is not always a habitat. A habitat is always a preference of one species, whereas an environment could be a preference of many species that could eventually become many habitats. Usually, the environment governs the properties of a habitat, but not vice versa Consider the following statements regarding diversity? 1. Alpha diversity : diversity between ecosystems 2. Beta diversity : the diversity within a particular area or ecosystem 3. Gamma diversity:overall diversity for the different ecosystems within a region Which of the above statements is/are correctly matched? (a) 3 only (b) 1 and 3 (c) 2 and 3 Ans A :

2 Alpha diversity refers to the diversity within a particular area or ecosystem, and is usually expressed by the number of species (i.e., species richness) in that ecosystem. For example, if we are monitoring the effect that British farming practices have on the diversity of native birds in a particular region of the country, then we might want to compare species diversity within different ecosystems, such as an undisturbed deciduous wood, a well-established hedgerow bordering a small pasture, and a large arable field. We can walk a transect in each of these three ecosystems and count the number of species we see; this gives us the alpha diversity for each ecosystem If we examine the change in species diversity between these ecosystems then we are measuring the beta diversity. We are counting the total number of species that are unique to each of the ecosystems being compare Gamma diversity is a measure of the overall diversity for the different ecosystems within a region. 3. Choose the incorrect pairs analysing their characteristic features and vegetation: 1. Stilt roots : Desert vegetation 2. Sloping Branches and needle like leaves : Tropical Rain Forests 3. Waxy stem and thorns : Desert Vegetation 4. Thick Canopy with strong undergrowth : Tropical Grassland. (a) 3 only (b) 1, 2 and 4 (c) 2, 3 and 4 (d) All the above Ans B. Stilt roots : Mangrove vegetation Sloping Branches and needle like leaves : It's seen in high altitudes and snowy taiga regions Waxy stem and thorns : Desert Vegetation Thick Canopy with strong undergrowth : Tropical Rain forest Go through the characteristic features of each vegetation 4. Which of the following statements is/are true regarding Ecotones? 1. It is a zone of tension because it has conditions intermediate to the adjacent ecosystems. 2. Edge effect can be observed in an ecotone. (a) 1 only (b) 2 only

3 (c) Both 1 and 2 (d) Neither 1 nor 2 Ans C Characteristics of Ecotone It may be narrow (between grassland and forest) or wide (between forest and desert). As it is a zone of transition, it has conditions intermediate to the adjacent ecosystems. Hence it is a zone of tension. Usually, the number and the population density of the species of an outgoing community decreases as we move away from community or ecosystem. A well-developed ecotones contain some organisms which are entirely different from that of the adjoining communities. In ecology, edge effects refer to the changes in population or community structures that occur at the boundary of two habitats (ecotone) 5. Which of the following can be the characteristics of Succession? 1. Decreased Productivity. 2. The shift of nutrients from' the reservoirs. 3. A gradual increase in the complexity of food webs. (b) 1 and 3 (c) 2 and 3 Ans C Succession is characterized by the following: 1. increased productivity, 2. the shift of nutrients from' the reservoirs, 3. increased diversity of organisms with increased niche development, and 4. a gradual increase in the complexity of food webs. 6. Consider the following statements regarding Food Chains and Food Webs in a an ecosystem: 1. A food chain illustrates the order in which a chain of organisms feed upon each other. 2. Even if any of the intermediate food chain is removed, the succeeding links of the chain will not be affected largely. 3. The food web provides only one alternative for food to most of the organisms. Which among the above statements is/are true?

4 (b) 1 only (c) 1 and 3 Ans B If any of the intermediate food chain is removed, the succeeding links of the chain will be affected largely. The food web provides more than one alternative for food to most of the organisms in an ecosystem and therefore increases their chance of survival. Also food availability and preferences of food of the organisms may shift seasonally. A food chain illustrates the order in which a chain of organisms feed upon each other 7. Which of the following pyramids is/are always upright? 1. Pyramid of Biomass 2. Pyramid of numbers 3. Pyramid of energy (a) 3 only (b) 1 and 3 (c) 2 and 3 Ans A Pyramid of numbers can be seen upright in a lake ecosystem while it is inverted in a tree ecosystem Pyramid of biomass is inverted in a lake or aquatic ecosystem Pyramid of energy is always upright as energy transferred will get reduced at each stage 8. Consider the statements regarding Ecological Efficiency: 1. It is the efficiency with which energy is transferred from one trophic level to the next percent laws is followed by every trophic level including green plants. 3. The energy loss is is mainly due to metabolism and respiration Which among the above statements is/are true? (b) 2 and 3 (c) 1 and 3

5 Ans D Ecological efficiency describes the efficiency with which energy is transferred from one trophic level to the next. transfer of energy follows 10 per cent law only 10 per cent of the energy is transferred to each trophic level from the lower trophic level The decreases at each subsequent trophic level is due to two reasons: 1. At each trophic a part of the available energy is lost in respiration or used up in metabolism. 2. A part of energy is lost at each transformation, i.e. when it moves from lower to higher trophic level as heat. 9. Which of the following are the characteristics of a pollutant that biomagnify? 1. It must be long lived 2. It should be mobile 3. It should be water soluble 4. It should be biologically inactive. (a) 1, 2 and 4 (b) 1 and 2 (c) 1,3 and 4 (d) All the above Ans B In order for biomagnification to occur, the pollutant must be: long-lived, mobile, soluble in fats, biologically active. E.g. DDT If the pollutant is soluble in water, it will be excreted by the organism. Pollutants that dissolve in fats, however, may be retained for a long time Which of the following are examples of negative interactions in an ecosystem? 1. Commensalism 2. Amensalism 3. Predation 4. Mutualism (a) 1,2 and 3 (b) 2,3 and 4 (c) 2 and 3

6 (d) All the above Ans C Negative interactions 1. Amensalism 2. Predation 3. Parasitism 4. Competition Positive Associations 1. Commensalism 2. Mutualism Neutral Interactions 1. Neutralism 11. Which of the following processes can add Nitrogen to the soil? 1. Excretion by animals 2. Thunder and lightning 3. Adding Fly ash to waste land 4. Decomposition of vegetation 5. Adding Urea based fertilizer to the soil. (a) 1, 2 and 5 (b) 1, 4 and 5 (c) 1, 2,4 and 5 (d) All the above Ans C Adding fly ash will not provide any nitrogen to the soil. Its a byproduct of coal based thermal power plants. Other processes can fix nitrogen to soil. 12. Consider the following characteristics and find the representing biome: 1. Temperature is uniform throughout the year 2. Seeding, flowering, fruiting and decaying do not take place in a seasonal pattern 3. Comprises a multitude of evergreen trees that yield hardwood. (a) Tropical Deciduous forest (b) Taiga Biome

7 (c) Temperate Rain Forest (d) Tropical Rain Forest Ans D Temperature is uniform throughout the year. The mean monthly temperatures are always around 27 C with very little variation. There is no winter. [Typical to Equatorial Rainforest Climate Precipitation is heavy and well distributed throughout the year. Annual average is always above 150 cm. In some regions the annual average may be as high as cm High temperature and abundant rainfall support a luxuriant tropical rain forest. Unlike the temperate regions, the growing season here is all the year round-seeding, flowering, fruiting and decaying do not take place in a seasonal pattern. The equatorial vegetation comprises a multitude of evergreen trees that yield tropical hardwood, e.g. mahogany, ebony, dyewoods etc 13. Which of the following statements are the possible effects of Eutrophication? 1. Algal Blooms restrict the penetration of sunlight resulting in death of aquatic plants. 2. It will increase is the dissolved oxygen content in water by increased photosynthesis by phytoplankton and algal blooms. (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2 Ans A Oxygen in aquatic ecosystem is replenished by photosynthetic aquatic plants. Algal Blooms restrict the penetration of sunlight resulting in death of aquatic plants, and hence restricts the replenishment of oxygen. The oxygen level is already depleted due to the population explosion of phytoplankton. Phytoplankton are photosynthetic during day time adding oxygen to aquatic ecosystem. But during nights, they consume far more oxygen as they respire aggressively. i.e. Algal blooms accentuate the rate of oxygen depletion as the population of phytoplankton is very high. 14. Recently There has been news that coral bleaching is prevalent over the coastal regions of Indian Ocean. In this regard which of the following conditions can help in robust development of coral reefs?

8 1. Tropical waters with diurnal and annual temperature ranges are very narrow. 2. High siltation with high river discharge 3. Shallow coastal waters. (b) 1 and 3 (c) 2 and 3 Ans B Stable climatic conditions: Corals are highly susceptible to quick changes. They grow in regions where climate is significantly stable for a long period of time. Perpetually warm waters: Corals thrive in tropical waters [30 N and 30 S latitudes, The temperature of water is around 20 C] where diurnal and annual temperature ranges are very narrow. Shallow water: Coral require fairly good amount of sunlight to survive. The ideal depths for coral growth are 45 m to 55 m below sea surface, where there is abundant sunlight available. Clear salt water: Clear salt water is suitable for coral growth, while both fresh water and highly saline water are harmful. Abundant Plankton: Adequate supply of oxygen and microscopic marine food, called plankton [phytoplankton], is essential for growth. As the plankton is more abundant on the seaward side corals grow rapidly on the seaward side. Little or no pollution: Corals are highly fragile and are vulnerable to climate change and pollution and even a minute increase in marine pollution can be catastrophic. 15. Which of the following regions of India have presence of coral reefs? 1. Andaman and Nicobar 2. Lakshadweep 3. Gulf of Kutch 4. Gulf of Mannar (a) 1, 2 and 3 (b) 1, 2 and 4 (c) 1. 3 and 4 (d) All the above Ans D : See the map Below

9 16. Recent urban floods showed importance of wetlands in the country. In this context consider the statements regarding Wetlands: 1. Wetlands are transition zones between terrestrial and aquatic ecosystems % of wetlands in India are under paddy cultivation. Which among the above statements is/are true? (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2 Ans C Wetlands are transition zones between terrestrial and aquatic ecosystems. E.g. Mangroves, lake littorals (marginal areas between highest and lowest water level of the lakes), floodplains (areas lying adjacent to the river channels beyond the natural levees and periodically flooded during high discharge in the river) and other marshy or swampy area Wetlands occupy 18.4% of the country's area of which 70% are under paddy cultivation 17. Consider the statements regarding Ramsar Convention: 1. Wise use of wetland is the central theme of ramsar conventions. 2. Montreux record under ramsar convention register the List of Wetlands of International Importance where changes in ecological character have occurred. 3. In India Keoladeo National Park, Loktak Lake and Chilika lake are under Montreux record

10 Which among the above statements is/are true? (b) 2 and 3 (c) 1 and 3 Ans A : At the center of the Ramsar philosophy is the wise use of wetlands. Wise use: maintenance of ecological character within the context of sustainable development The Montreux Record is a register of wetland sites on the List of Wetlands of International Importance where changes in ecological character have occurred, are occurring, or are likely to occur as a result of technological developments, pollution or other human interference. It is maintained as part of the Ramsar List Chilika Lake was removed from the register in 2002 in light of the improved conditions of the lake. In fact, Chilika lake is the first Ramsar site in Asia to be removed from the Montreux record 18. Which of the following characteristics can be seen in a mangrove plant as an adaptive mechanism? 1. Viviparity mode of reproduction 2. Stilt root 3. Pneumatophores 4. Waxy Leaf (a) 1, 2 and 4 (b) 1, 3 and 4 (c) 1, 2 and 3 (d) All the above Ans C They produces pneumatophores (blind roots) to overcome respiration problem in the anaerobic soil conditions Adventitious roots which emerged from the main trunk of a tree above ground level are called stilt roots Mangroves exhibit Viviparity mode of reproduction. i.e. seeds germinate in the tree itself (before falling to the ground). Waxy leaf is a characteristics of Desert vegetation

11 19. Ministry of Environment and Forest is pushing for use of Fly ash in various sectors. In this regard which of the following are the advantages of using Fly ash? 1. It can be used in production of cement. 2. It can be used in reclamation of land. 3. It can be used in filling abandoned mines. 4. Dissolved oxygen content in water sources can be improved with Fly ash Select the answer using the codes given below. (a) 1, 3 and 4 (b) 1, 2 and 3 (c) 1 and 3 (d) All the above Ans B Cement can be replaced by fly ash up to 35%, thus reducing the cost of construction, making roads, etc. Fly ash bricks are light in weight and offer high strength and durability. Fly ash is a better fill material for road embankments and in concrete roads. Fly ash can be used in reclamation of wastelands. Abandoned mines can be filled up with fly ash. Fly ash can increase the crop yield and it also enhances water holding capacity of the land Dissolved oxygen can t be improved with Flyash. 20. Consider the statements regarding Ecological Succession: 1. Succession would occur faster in area existing in the middle of the large continent. 2. Climax community is stable and ecological succession normally stops here. 3. Unlike in the primary succession, the secondary succession starts on a well developed soil. Which among the above statements is/are true? (b) 2 and 3 (c) 1 and 3 Ans D Succession would occur faster in area existing in the middle of the large continent. This is because, here seeds of plants belonging to the different seres would reach much faster, establish and ultimately result in climax community.

12 The terminal (final) stage of succession forms the community which is called as climax community. A climax community is stable, mature, more complex and long lasting. A mature or climax community may be destroyed by natural events such as floods, droughts, fires, or storms or by human interventions such as deforestation, agriculture, overgrazing, etc Unlike in the primary succession, the secondary succession starts on a well developed soil already formed at the site. Thus secondary succession is relatively faster as compared to primary succession which may often require hundreds of years.