OBJECTIVE QUESTIONS FOR NEET AIIMS JIPMER www wisedane
OBJECTIVE QUESTIONS FOR NEET AIIMS JIPMER www. wisedane. com
BIOLOGY ECOSYSTEM SET 2 MCQ’s www. wisedane. com
Q 1. The drop in air temperature at a rate of 6. 5 °C per 1000 m increase in altitude of troposphere is known as (a) Environmental lapse rate (b) Environmental degradation (c) Green house effect (d) Global warming www. wisedane. com
ANSWER (A) EXPLANATION Ø As the pressure gets lower in higher altitude the temperature decreases. The rate of decrease of temperature with elevation is known as the adiabatic lapse rate or environmental lapse rate, which is approximately 6. 5 °C per kilometer (or 5. 4 °F per 1000 feet) of altitude. Ø Of course, this varies from location to location. We can use observations to determine the lapse rate of a particular location. The observations are gathered from a miniature weather-monitoring station (smaller than a shoe box) that is attached to a balloon and released into the air twice a day at various sites throughout the world called a radiosonde www. wisedane. com
Q 2. Zone consisting air, water and soil is known as (a) Hydrosphere (b) Atmosphere (c) Lithosphere (d) Biosphere www. wisedane. com
ANSWER (B) EXPLANATION Ø Atmosphere Ø Outermost shell of a terrestrial-type planet or natural satellite that is defined by its rigid mechanical properties is known as lithosphere Ø Hydrosphere is the combined mass of water found on, under, and above the surface of a planet. Ø The biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, geosphere, hydrosphere, and atmosphere www. wisedane. com
Q 3. Word oikos means _____ and logos means _______ (a) Houses and study of (b) Study and houses (c) Only houses (d) Study of people www. wisedane. com
ANSWER (A) EXPLANATION Ø Logos is a Greek word meaning logic. Logos is a literary device that can be defined as a statement, sentence or argument used to convince or persuade the targeted audience by employing reason or logic. In everyday life, arguments depend upon pathos and ethos besides logos. Ø The ancient Greek word oikos refers to three related but distinct concepts: the family, the family's property, and the house www. wisedane. com
Q 4. Which one of the following aspects is not a component of functional unit of ecosystem? (A) productivity (B) decomposition (C) energy flow (D) ecological pyramids www. wisedane. com
ANSWER (D) EXPLANATION Ø Interaction of biotic and abiotic components result in a physical structure, that is characteristics of each type of ecosystem Components of ecosystsem function as one single unit. Ø Four important functions aspects of the ecosystem are (i) Productivity (ii) Decomposition, (iii) Energy flow and (iv) Nutrient cycling. Ecological pyramids are graphic representation of number, biomass and energy flow in an ecosystem. www. wisedane. com
Q 5. In a comparative study of grassland ecosystem and pond ecosystem, it may be observed that (A) the abiotic components are almost similar (B) the biotic components are almost similar (C) both biotic and abiotic components are different (d) primary and secondary consumers are similar www. wisedane. com
ANSWER (C) EXPLANATION Ø Grassland ecosystem is a terrestrial ecosystem and pond ecosystems is an aquatic ecosystem, hence both their abiotic and biotic components would be different. www. wisedane. com
Q 6. _____ is the rate of production of organic matter by consumers. (A) primary productivity (B) secondary productivity (C) net primary productivity (D) gross primary productivity www. wisedane. com
ANSWER (B) EXPLANATION Ø The rate at which food energy is assimilated at the tropic level of consumers is called secondary productivity. In other words, the rate of synthesis of organic matter by consumers is called as secondary productivity. Ø The primary producers have produced the food for consumers, and secondary productivity reflects only one utilization of this food for the production of consumer biomass. www. wisedane. com
Q 7. Primary productivity depends upon (A) light and temperature (B) water and nutrients (C) photosynthetic capacity of producers (D) all of these www. wisedane. com
ANSWER (D) EXPLANATION Ø The primary productivity of an ecosystem is the rate at which biomass or organic matte r is produced per unit is a per unit time by plants (primary producers). Ø Primary productivity depends upon plant species of the area, their photosynthetic capacity, availability of nutrients, solar radiations, precipitation, soil type and a number of other environmental factors. www. wisedane. com
Q 8. Read the given statements and select the correct option. Statement 1: Net primary productivity is less than the gross primary productivity. Statement 2: Net primary productivity is equal to the gross primary productivity minus the respiration losses. A. Both statements 1 and 2 are correct and statement 2 is the correct explanation of statement 1. B. Both statements 1 and 2 are correct but statement 2 is not the correct explanation of statement 1. C. Statement 1 is correct and statement 2 is incorrect. D. Both statements 1 and 2 are incorrect. www. wisedane. com
ANSWER (A) EXPLANATION Ø Gross primary productivity (GPP) of an ecosystem is the rate of production of organic matter during photosynthesis. Net primary productivity (NPP) is the amount of organic matter stored by producers per unit area per unit time. Gross primary productivity respiration losses is the net primary productivity, NPP = GPP – R. www. wisedane. com
Q 9. Arrange the following ecosystems in increasing order of their mean NPP (tons / ha / year). A. Tropical deciduous forest B. Temperate coniferous forest C. Tropical rain forest D. Temperate deciduous forest (a) B<A<D<C (b) D<B<A<C (c) A<C<D<B (d) B<D<A<C www. wisedane. com
ANSWER (D) EXPLANATION Ø Temperate coniferous forest Ø Temperate deciduous forest Ø Tropical rain forest www. wisedane. com
Q 10. The annual net primary productivity of the whole biosphere is approximately. (A) 150 billion tons (B) 160 billion tons (C) 170 billion tons (D) 180 billion tons. www. wisedane. com
ANSWER (D) EXPLANATION • The annual net primary productivity of the whole biosphere is approximately 180 billion tons www. wisedane. com
Q 11. Productivity at the second trophic level is always A. greater than the productivity at the first trophic level B. less than the productivity at the first trophic level C. Equal to the productivity at the first trophic level D. extremely variable compared to the productivity at the first trophic level. www. wisedane. com
ANSWER (B) EXPLANATION Ø Productivity at second trophic level is always less than productivity at first trophic level. Ø This is because only 10% of energy is transferred from one trophic level to another. Thus decrease in energy would result in decrease in productivity. www. wisedane. com
Q 12. The rate of formation of new organic matter by rabbit in a grassland is called A. Net productivity B. Secondary productivity C. Net primary productivity D. Gross primary productivity www. wisedane. com
ANSWER (B) EXPLANATION Ø The rate of formation of new organic matter by rabbit in a grassland is called Secondary productivity www. wisedane. com
Q 13. The biomass available for consumption by the herbivores and the decomposers is called A. Net primary productivity B. Secondary productivity C. Standing crop D. Gross primary productivity www. wisedane. com
ANSWER (A) EXPLANATION Ø The amount of energy accumulation in green plants as biomass or organic matter per unit area over a time period is known as primary productivity. The rate of total capture of energy, or the rate of total production of organic material (biomass) is known as gross primary productivity. However, while the energy capturing process is operating in the green tissues, these as well as other tissues are consuming energy in respiration. Ø The balance energy or biomass remaining after meeting the cost of respiration of producers is called net primary productivity: net primary productivity = Gross primary productivity -Respiration rate. The net primary productivity results in the accumulation of plant biomass, which serves as the food of herbivores and decomposers. www. wisedane. com
Q 14. The rate of conversion of light energy into chemical energy of organic molecules in an ecosystem is A. Net primary productivity B. Gross primary productivity C. Secondary productivity D. Gross secondary productivity www. wisedane. com
ANSWER (B) EXPLANATION Ø The rate of conversion of light energy into chemical energy of organic molecules in an ecosystem is Gross primary productivity www. wisedane. com
Q 15. Which one of the following exhibits least productivity? (a) Salty marches (b) Grasslands (c) Open oceans (d) Coral reefs www. wisedane. com
ANSWER (C) EXPLANATION Ø In oceans, there are lots of nutrients but no sufficient sunlight is available in deep areas hence, oceans have least productivity. Ø Grasslands are less productive ecosystem with annual productivity of 200 -1000 gm/m 2. Ø Maximum productivity can be seen in coral reefs followed by estuaries. Salt marshes are estuaries where brackish and salt water mix. Ø Salt marsh plants (halophytes) are salt tolerant and adapted to water levels that fluctuate with tides. Tides carry in the nutrients that stimulate plant growth in marshes. www. wisedane. com
Q 16. Earthworms and bacteria are called (a) Producers (b) Consumers (c) Decomposers (d) None of these www. wisedane. com
ANSWER (C) EXPLANATION Ø Decomposers are organisms that get their energy by breaking down dead or decaying matter Ø Eg. Microorganisms, termites, worms, fungi, and bacteria Ø These decomposers speed up the decay process that releases nutrients back into the food chain for use by plants www. wisedane. com
Q 17. Region where fresh water meets salt water is called (a) Sea (b) Lake (c) River (d) Estuarine www. wisedane. com
ANSWER (D) EXPLANATION Ø Brackish water condition commonly occurs when fresh water meets seawater. The most extensive brackish water habitats worldwide are estuaries, where a river meets the sea. Ø The River Thames flowing through London is a classic river estuary www. wisedane. com
Q 18. The Ecological pyramid that is always upright (a) Pyramid of energy (b) Pyramid of biomass (c) Pyramid of number (d) None of these www. wisedane. com
ANSWER (A) EXPLANATION Ø The pyramids of numbers and biomass may be upright or inverted depending upon the nature of the food chain in the particular ecosystem, whereas pyramids of energy are always upright. www. wisedane. com
Q 19. “Green house effect” with respect to global warming refers to - (a) Cooling & moist condition (b) Warming effect (c) Increased rainfall & greenery (d) Desertification www. wisedane. com
ANSWER B EXPLANATION Ø The trapping of energy from the sun by certain gases in the atmosphere leading to the rise in earth’s temperature is known as Green house effect www. wisedane. com
Q 20. In India, Tropical rain forest occurs in- A. Jammu and Kashmir B. Andaman & Nicobar C. Uttar Pradesh D. Himachal Pradesh www. wisedane. com
ANSWER (B) EXPLANATION Ø Tropical rainforests of India are found in the Andaman and Nicobar Islands, the Western Ghats, which fringe the Arabian Sea, the coastline of peninsular India, and the greater Assam region in the north-east. Small remnants of rainforest are found in Odisha state. www. wisedane. com
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