7
Energy Flow in an Ecosystem
IMPORTANT POINTS:
▸ Producers, primary consumers (herbivores), secondary consumers (carnivores), apex consumers are the different trophic levels in a food chain. Some animals are omnivores. ▷ Many food chains that are interconnected at various levels form food web. ▸ The flow of energy is from lower trophic level to higher trophic level. The energy transferred to the next level is about 10% of previous level. Thus, very few energy reaches the apex level. This is represented by an energy pyramid. ▸ The cyclical flow of nutrients within an ecosystem is called the bio-geo-chemical cycle. ▸ Bio-geo-chemical cycles are of two types (i) Gaseous cycles e.g. nitrogen, oxygen, carbon diox- ide, water vapour etc. (ii) Sedimentary cycle e.g. iron, calcium, phosphorous etc. ►Following are the important processes in the oxygen cycle- (i) Respiration (ii) combustion (iii) photosynthesis. These are also the important processes in the carbon cycle. ►Following are the important processes in the nitrogen cycle-(i) Nitrogen fixation-Conversion of nitrogen into nitrates and nitrites. (ii) Ammonification-Release of ammonia though decomposition of dead bodies and excretory wastes of organisms. (iii) Nitrification-Conversion of ammonia into nitrite and then nitrate. (iv) Denitrification - Conversion of nitrogen compounds into gaseous nitrogen.
***SPECIMEN QUESTIONS ++++
(1) Almost all the organisms cannot use- in free state.
(1) carbon dioxide
(2) nitrogen
(3) oxygen
(4) decomposers
Explanation: Plants and animals excep
4) water anaerobic microorganisms cannot use nitrogen present in the atmosphere. Plants get nitrogen compounds from the soil and synthesize their proteins. Animals get the proteins from these plants. ..
Option 2 is correct.
(2) The animals which are directly dependent on plants for their food are called
(1) autotrophs
(2) carnivores
(3) herbivores
(4) decomposers
Explanation: The animals which are directly dependent on plants are called herbivores.
Option 3 is correct.
**QUESTIONS FOR PRACTICE ++
(1) Producers use only- % of energy they
receive from the sun.
(1) 100
(2)0.1
(3) 10
(4) 25
Answers:- (3) 10
(2) The flow of nutrients in an eco-system is
(1) one-way
(2) two-way
(3) three-way
(4) cyclic
Answers:- (4) cyclic
(3) Which of the following animal can be included in the fourth trophic level?
(1) Cow
(2) Frog
(3) Hawk
(4) Grass hopper
Answers:-(3) Hawk
(4) present in chloroplasts absorb the energy received from the sun.
(1) Chlorophyll
(2) Ribosomes
(3)DNA
(4) Hormones
Answers:-(1) Chlorophyll
(5) Which of the following is not required for the photosynthesis?
(1) Oxygen
(2) Carbon dioxide
(3) Sun light
(4) Chlorophyll
Answers:-(1) Oxygen
(6)Carbon dioxide enters the leaf through-
(1) veins
(2) Stomata
(3) waxy layer
(4) roots
Answers:-(2) Stomata
(7) Complete the following reaction of photosynthesis. 6 CO, + 6 HO → CH,O +
(1)0,
(2) 60,
(3) 120,
(4)30,
Answers:-(2) 60,
(8) Complete the following: Producers Herbivores...→→Decomposers
(1) Plants
(2) Saprophytes
(3) Camivores
(4) Autotrophs
Answers:-(3) Camivores
(9)The flow of energy in any eco-system is-
(1) one-way
(2) two-way
(3) three-way
(4) cyclic
Answers:-(1) one-way
(10)is omnivorous.
(1) Elephant
(2) Jackal
(3) Bear
(4) Lion
Answers:-(3) Bear
(11) Complete the food chain. Crops → Mouse→→→ Eagle
(1) Elephant
(2) Snake
(3) Fish
(4) Tiger
Answers:-(2) Snake
(12) Decomposition of organic matter is ( reaction.
(1) aerobic
(2) exothermic
(3) anaerobic
(4) reversible
Answers:-(1) aerobic
(13) Which of the following processes is not related to nitrogen cycle?
(1) Nitrogen fixation
(2) Ammonification
(3) Denitrification
(4) Combustion
Answers:-(4) Combustion
(14) In the process of , oxygen is not required. (1) Combustion
(2) Decomposition
(3) Rusting
(4) Photosynthesis
Answers:-(4) Photosynthesis
(15) Oxygen is not an important constituent of (2 nutrient
(1) Fats
(2) Proteins
(3) Minerals
(4) Carbohydrates
Answers:-(3) Minerals
(16)- ____. is the essential constituent of organisubstances
(1) Carbon
(2) Nitrogen
(3) Sulphur
(4) Cald
Answers:-(1) Carbon
(17) Complete the following reaction:
CHO, +60, +6 H₂O+ energy
(1)CH,
(2)6 CO,
(3)60,
(4) 120
Answers:-(2)6 CO,
(18) For the synthesis of proteins, important constituent. is
(1) CO₂
(2) N₂
(3) 0,
(4)P
Answers:-(2) N₂
(19) Microbes- do the nitrogen fixation.
(1) yeast
(2) Clostridium
(3) Rhizobium
(4) Lactobacilli
Answers:- (3) Rhizobium
(20) Find the odd man out.
(1) Respiration
(2) Combustion
3) Rusting
4) (4) Photosynthesis
Answers:-(4) Photosynthesis
Hints for difficult questions)
(20) Photosynthesis does not require oxygen, al other processes require oxygen.
Option4 is correct.
कोणत्याही टिप्पण्या नाहीत:
टिप्पणी पोस्ट करा