Maharashtra Board Class 9 Science Solution Chapter 7 – Energy Flow in an Ecosystem
Balbharati Maharashtra Board Class 9 Science Solution Chapter 7: Energy Flow in an Ecosystem. Marathi or English Medium Students of Class 9 get here Energy Flow in an Ecosystem full Exercise Solution.
Std |
Maharashtra Class 9 |
Subject |
Science Solution |
Chapter |
Energy Flow in an Ecosystem |
1.) Complete the following table.
Ans:
1) Carbon cycle:
- Biotic process: Release of oxygen through the process of photosynthesis and release of carbon dioxide through the process of respiration
- Abiotic process: Release of carbon dioxide through burning of fossil fuels and wood.
2) Oxygen cycle:
- Biotic process: Release of oxygen through the process of photosynthesis and consumption of it through the process of respiration.
- Abiotic process: Oxygen is released when water molecule is broken due to light which is due to the photo dissociation of water in the atmosphere.
3) Nitrogen cycle:
- Biotic process: Nitrogen fixation, nitrification and ammonification.
- Abiotic process: Nitrogen fixation in the atmosphere and denitrification.
2.) Correct and rewrite the following statements and justify your answer.
a) Carnivores occupy the second tropic level in the food chain.
Ans:
- The each level in the food chain is called as tropic level which is the level at which organism obtain it’s food in the chain.
- Carnivores occupy the third tropic level in the food chain as second tropic level is occupied by the herbivores which depends on plants for their food.
- After herbivores the next tropic level is the Carnivores in the food chain.
b) The flow of nutrients in an ecosystem is considered to be a ‘one way transport’.
Ans:
- As the flow of energy in an ecosystem is one way, the flow of nutrients is cyclical.
- And these cyclical flow of nutrients within the ecosystem is called as bio-geo-chemical cycle.
- Also those nutrients which are needed for the growth of are transferred continuously from abiotic to biotic and biotic to abiotic factors in an ecosystem.
- The cycle is occurring within the biosphere which is formed from lithosphere, atmosphere and the hydrosphere.
c) Plants in an ecosystem are called as primary consumers.
Ans:
Plants are the primary producers as they are autotrophic in nature that means they produces their own food and other organisms depends on the plants for their food and to attain their nutrition level.
3.) Give reasons.
a) Energy flow through an ecosystem is one way.
Ans:
- The plants which are the primary producers produces food by converting solar energy into chemical energy. The primary consumers which are the herbivores depends on the plants for their nutrition and food.
- But, only 10% of energy will be transferred from one tropic level to next tropic level as given by energy law.
- And hence we can say that the solar energy taken by primary producers i.e. plants can’t send back to the sun and the energy consumed by the primary consumers herbivores can’t send their energy back to the primary producers.
- And the energy flow is only from one tropic level to next tropic level that means the energy flow is in only one direction. Hence, we can say that the energy flow in the food chain is unidirectional way or one way only.
b) Equilibrium is necessary in the various bio-geo-chemical cycle.
Ans:
- As the flow of energy in an ecosystem is one way, the flow of nutrients is cyclical.
- And these cyclical flow of nutrients within the ecosystem is called as bio-geo-chemical cycle.
- Also those nutrients which are needed for the growth of are transferred continuously from abiotic to biotic and biotic to abiotic factors in an ecosystem.
- The cycle is occurring within the biosphere which is formed from lithosphere, atmosphere and the hydrosphere.
- The recycling of bio-geo-chemicals is depends on the amount of energy transferred within the ecosystem. If these energy balance is disturbed then ecosystem collapses and nature is in danger.
- Hence, to make balance in nature and ecosystem the equilibrium is necessary in the various bio-geo-chemical cycle.
c) Flow of nutrients through an ecosystem is cyclic.
Ans:
- Flow of nutrients through an ecosystem is cyclic because nutrients are transferred from one tropic level to next tropic level and finally returns to initial state or tropic level. The nutrients are transferred in cyclic way in an ecosystem as given below:
- Primary producers which are the green plants and they are autotrophs producing their own food by using solar energy from the sun by process of photosynthesis.
- The primary consumers which are the herbivores depends on primary producers for their nutrients.
- Then next tropic level depends on the primary consumers for their nutrition.
- In this way, the next tropic levels depends on the tropic levels below them for their food and nutrients.
- When this nutrients reach to the highest tropic level after that these nutrients are transferred to soil by the process of decomposition. The organism such as Fungi and bacteria helps in the process of decomposition.
- Again these energy is used by plants which are growing in soil and in this way it forms cycle of nutrients flow in an ecosystem.
4.) Explain the following cycle in your own words with suitable diagrams.
a) Carbon cycle:
- In carbon cycle there is circulation and recycling of carbon takes place from atmosphere to the living organisms and then after the death of living organisms to the again atmosphere.
- Through the process of photosynthesis and respiration the abiotic carbon is circulated and recycled into the biotic form.
- Initially, the carbon dioxide from atmosphere is taken by green plants and they produces carbohydrates by using sunlight in the process of photosynthesis.
- Also, they produces proteins and fats which are carbon rich compounds also.
- The next tropic level that means herbivores depends on the green plants for their nutrition.
- Next tropic level means Carnivores which are dependent on the herbivores for their food.
- In this way, the biotic carbon is transferred from green plants to herbivores and then herbivores to Carnivores and finally Carnivores to apex consumers.
The main process involved in the carbon cycle are photosynthesis and respiration which are given as below:
6CO2 + 12H2O -> C6H12O6 + 6H2O + 6O2 in the presence of sunlight and chlorophyll
C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy
In the mitochondria.
- After the death of all consumers in the carbon cycle they get decomposed by organisms like fungi and bacteria and releases carbon dioxide in the atmosphere.
- Again these carbon dioxide from the atmosphere is used by the green plants.
- In this way, carbon is transferred from one living organisms to another living organisms in the carbon cycle.
b) Nitrogen cycle:
- We know that the 78% of part of atmosphere is composed of nitrogen.
- The recycling and circulation of nitrogen gas in the nature through biotic and abiotic process to maintain the cycle of nature is called as the nitrogen cycle.
- Nitrogen is the main part of protein and nuclic acids. Nitrogen is mainly inactive and hence cannot react directly with other compounds. But this free form of nitrogen is not used directly by the organisms.
- In nitrogen cycle, nitrogen gas from atmosphere is converted into simple molecular form in the soil and water.
- While in living organisms it get converted into complex form and after its reduction again it is released into the atmosphere in the simple molecular form.
The steps involved in the nitrogen cycle are as given below:
1) Nitrogen fixation:
Nitrogen fixation process is done by the organisms like Rhizobium, azotobacter and blue green algae which converts atmospheric nitrogen into the water soluble nitrates form as given in the reaction.
N2 -> NO3- or NH4
2) Nitrification:
The second step involved is the Nitrification in which ammonia is converted into nitrites and again into the nitrates by the bacteria like nitrosomonas and nitrobacter. The process occured in this step is given by,
NH3 ->NO2- -> NO3-
3) Assimilation:
Assimilation is the process in which NH3 and NO3 are converted into the biological tissues.
4) Ammonification:
In this process the complex dead organisms are decomposed into ammonia by the organisms like bacteria and fungi.
Organic nitrogen compounds -> NH4+
5) Denitrification:
In this process the nitrates from the soil are reduced and releases again nitrogen into the atmosphere.
NO3- -> N2
c) Oxygen cycle:
- The 21% portion of atmosphere is containing oxygen and oxygen is also present in the hydrosphere and the lithosphere.
- In oxygen cycle the circulation and recycling of oxygen within the biosphere takes place.
- Mainly the biotic and abiotic factors are also involved in the oxygen cycle.
- The oxygen is produced and also used in large amount in the atmosphere.
- We know that, oxygen is highly reactive and reacts with the elements in nature. Also it exist in nature in various forms like oxygen, water, carbon dioxide, organic compounds etc.
- The oxygen cycle occuring in the biosphere is very complex in nature.
- Oxygen is produced in the process of photosynthesis and it is used in many process such as respiration, combustion, decomposition, rusting, corrosion etc.
5.) What would you do to help the maintain the equilibrium in various bio-geo-chemical cycle? Explain in brief.
Ans:
- The equilibrium maintained in the bio-geo-chemical cycles helps in keeping and maintaining life on the earth. If any disturbance is produced in this equilibrium then there will be collapsing of bio-geo-chemical cycle.
- As we studied various biological cycles in which we have seen that plants plays a very important role in maintaining the life on the earth. The existence of life on the earth is only due to the plants. If we have given harm to them then we see the dangerous effects of nature in future.
- The increase in industrialization and population increased the Deforestation and also due to pollution.
In order to maintain equilibrium in all the biological cycles we have to follow the following steps.
- We have to plant more trees and reduce deforestation.
- We have to less use the carbon emitting materials or devices.
- We have conserve water by using it in need only.
- We have to use renewable energy sources instead of non renewable energy sources.
6.) Explain in detail the interrelationship between the food chain and the food web.
Ans:
- The food chain represents the energy flow in various animals.
- The number of organisms involved in the food chain decide the length of the food chain.
- It gives the relationship between the animals.
- The energy flow in food chain is from producers to primary consumers then to secondary consumers next to tertiary consumers then to human and again return to the producers.
- Food web is the representation of various food chains and the organisms who eats what type of food.
- In food web, starting is from producers then it is branched in different species and interconnected according to the species who eats what type of food. In this way, food web is the web interconnected between species with their type of food.
7.) State the different types of bio-geo-chemical cycles and explain the importance of those cycles.
Ans:
- The bio-geo-chemical cycles are developed or existing to maintain the concentration of naturally occurring substances in the environment.
- There are some cycles which circulates and recycled these naturally occurring substances and that cycles are the bio-geo-chemical cycles.
- Hence, bio-geo-chemical cycles gives the energy and nutrients flow between living organisms and the non living organisms also.
- There are mainly two types of bio-geo-chemical cycles.
1) Gaseous cycle:
- In gaseous cycle the reservoir pool acts as the atmosphere and hydrosphere.
- Carbon cycle, nitrogen cycle are involved in the gaseous cycle.
2) Sedimentary cycle:
In Sedimentary cycle the reservoir pool is the lithosphere and phosphorus cycle, sulphur cycle are involved in the sedimentary cycle.
Nitrogen cycle:
- We know that the 78% of part of atmosphere is composed of nitrogen.
- The recycling and circulation of nitrogen gas in the nature through biotic and abiotic process to maintain the cycle of nature is called as the nitrogen cycle.
- Nitrogen is the main part of protein and nucleic acids. Nitrogen is mainly inactive and hence cannot react directly with other compounds. But this free form of nitrogen is not used directly by the organisms.
- In nitrogen cycle, nitrogen gas from atmosphere is converted into simple molecular form in the soil and water.
- While in living organisms it get converted into complex form and after its reduction again it is released into the atmosphere in the simple molecular form.
The steps involved in the nitrogen cycle are as given below:
1) Nitrogen fixation:
Nitrogen fixation process is done by the organisms like Rhizobium, azotobacter and blue green algae which converts atmospheric nitrogen into the water soluble nitrates form as given in the reaction.
N2 -> NO3- or NH4
2) Nitrification:
The second step involved is the Nitrification in which ammonia is converted into nitrites and again into the nitrates by the bacteria like nitrosomonas and nitrobacter. The process occured in this step is given by,
NH3 -> NO2- -> NO3-
3) Assimilation:
Assimilation is the process in which NH3 and NO3 are converted into the biological tissues.
4) Ammonification:
In this process the complex dead organisms are decomposed into ammonia by the organisms like bacteria and fungi.
Organic nitrogen compounds -> NH4+
5) Denitrification:
In this process the nitrates from the soil are reduced and releases again nitrogen into the atmosphere.
NO3- -> N2
Oxygen cycle:
- The 21% portion of atmosphere is containing oxygen and oxygen is also present in the hydrosphere and the lithosphere.
- In oxygen cycle the circulation and recycling of oxygen within the biosphere takes place.
- Mainly the biotic and abiotic factors are also involved in the oxygen cycle.
- The oxygen is produced and also used in large amount in the atmosphere.
- We know that, oxygen is highly reactive and reacts with the elements in nature. Also it exist in nature in various forms like oxygen, water, carbon dioxide, organic compounds etc.
- The oxygen cycle occuring in the biosphere is very complex in nature.
- Oxygen is produced in the process of photosynthesis and it is used in many process such as respiration, combustion, decomposition, rusting, corrosion etc.
Carbon cycle:
- In carbon cycle there is circulation and recycling of carbon takes place from atmosphere to the living organisms and then after the death of living organisms to the again atmosphere.
- Through the process of photosynthesis and respiration the abiotic carbon is circulated and recycled into the biotic form.
- Initially, the carbon dioxide from atmosphere is taken by green plants and they produces carbohydrates by using sunlight in the process of photosynthesis.
- Also, they produces proteins and fats which are carbon rich compounds also.
- The next tropic level that means herbivores depends on the green plants for their nutrition.
- Next tropic level means Carnivores which are dependent on the herbivores for their food.
- In this way, the biotic carbon is transferred from green plants to herbivores and then herbivores to Carnivores and finally Carnivores to apex consumers.
The main process involved in the carbon cycle are photosynthesis and respiration which are given as below:
6CO2 + 12H2O -> C6H12O6 + 6H2O + 6O2 in the presence of sunlight and chlorophyll
C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy
In the mitochondria.
- After the death of all consumers in the carbon cycle they get decomposed by organisms like fungi and bacteria and releases carbon dioxide in the atmosphere. Again these carbon dioxide from the atmosphere is used by the green plants.
- In this way, carbon is transferred from one living organisms to another living organisms in the carbon cycle.
8.) Explain the following with suitable example.
a) What type of changes occur in the amount of energy during its transfer from plants to apex consumers.
Ans:
- As the energy is consumed from lower to higher tropic level so when we move from lower to higher tropic level there will be reduction in energy.
- Hence, we can say that energy is lost while transferring from one tropic level to next tropic level in the form of metabolic heat when it will be consumed.
- According to 10% rule, while transferring the energy from one tropic level to next tropic level then only 10% of energy will be transferred to next tropic level.
- The following pyramidal diagram in case of aquatic ecosystems shows the energy consumed in different tropic level.
- As we see in this pyramidal diagram, it has been seen that as we go from lower to higher tropic level the amount of energy transferred decreases.
b) What are the difference between flow of matter and if energy in an ecosystem? Why?
Ans:
- The main difference between flow of matter and energy is that the flow of matter is cyclic that means it is recycled and come back to initial state again. While the flow of energy is the unidirectional way and hence it cannot be recycled.
- The flow of matter includes the following steps.
- When dead organisms are broken by decomposers they release nutrients.
- There’s nutrients are absorbed by the plants from the soil through their roots.
- When these plants are eaten by the primary consumers then these nutrients are taken up by the primary consumers.
- In this way, the higher consumers depends on the lower consumers for the nutrients.
- And finally when the living organisms get die then they get decomposed again and the cycle is repeated continuously.
- While we have seen that, the energy flow in an ecosystem is the unidirectional way.
- In this way, energy is transferred from photosynthetic plants to herbivores then to Carnivores and finally to decomposers.
- In this way, lower and lower amount of energy will be transferred.
- Because while transferring the energy some amount energy is lost in the environment in the form of heat.