NCERT exemplar Class 10 Science solutions chapter 15 helps understand the ecosystem whether it is natural or artificial. The chapter describes how life depends on our environment. The teaching faculty at Careers360 have taken accuracy and expressiveness as the base while preparing the NCERT exemplar Class 10 Science chapter 15 solutions. While learning about the environment, students can get the maximum benefit and enhance their learning capabilities with the help of these solutions.
The NCERT exemplar Class 10 Science chapter 15 solutions are adequate to understand the chapter on ‘Our Environment. These NCERT exemplar Class 10 Science solutions chapter 15 covers the complete chapter 15 CBSE 10 Syllabus.
NCERT Exemplar Class 10 Science Solutions Chapter 15-MCQ
Question:1
Which one of the following is an artificial ecosystem?
(a) Pond
(b) Crop field
(c) Lake
(d) Forest
Ans. (b)
An artificial ecosystem is a human made system of plants, animals, and people living
in an area together with their surroundings. These are not self-sustainable.
Pond, lake and forests are not human made.
Crop field is an artificial ecosystem as they are not self-sustainable.
Therefore option (B) is correct
Question:2
In a food chain, the third trophic level is always occupied by
(a) carnivores
(b) herbivores
(c) decomposers
(d) producers
Answer:(a)
In a food chain, the third trophic level is always occupied by carnivores that feed on herbivores.
Tropic levels
1. Producers/autotrophs ---- level - 1
2. Herbivores ---- level – 2
3. Carnivores ---- level – 3
4. Higher Carnivores ---- level – 4
Therefore option (A) is correct
Question:3
An ecosystem includes
(a) all living organisms
(b) non-living objects
(c) both living organisms and non-living objects
(d) sometimes living organisms and sometimes non-living objects
Answer:(c)
The ecosystem consists of biotic components comprising living organisms and abiotic components comprising physical factors like temperature, rainfall etc.
Ecosystem includes interaction among biotic and abiotic components, i.e., both living organisms and non-living objects.
Therefore option (C) is correct
Question:6
Depletion of ozone is mainly due to
(a) chlorofluorocarbon compounds
(b) carbon monoxide
(c) methane
(d) pesticides
Answer:(a)
Depletion of ozone is mainly due to chlorofluorocarbons (CFCs). These are synthetic chemicals that are used as refrigerants and in fire extinguishers. Ozone is a stable molecule but due to the presence of chlorofluorocarbons in the atmosphere has led to the ozone hole as it converts ozone molecule to oxygen. Prevalent use of chlorofluorocarbons has led to an ozone hole near the poles.
Therefore option (A) is correct
Question:7
Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called
(a) decomposers
(b) producers
(c) herbivores
(d) carnivores
Answer:(b)
Decomposer is an organism that decomposes, or breaks down, organic material such as the remains of dead organisms.
Organisms which synthesize their own food from inorganic compounds using radiant
energy are called producers or autotrophs e.g., all green plants, blue-green algae etc.
Animals that eat plants exclusively are herbivores, and animals that eat only meat are carnivores.
Therefore option (B) is correct
Question:9
Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the
(a) food web
(b) ecological pyramid
(c) ecosystem
(d) food chain
Answer:(a)
Organisms of a higher trophic level feeding on several types of organisms belonging to a lower trophic level constitute the food web.
An ecological pyramid is a graphical representation of the relationship between different organisms in an ecosystem.
An ecosystem is a network of living beings related to the nonliving beings of their environment, interacting as a system.
The food chain is a linear sequence of organisms where nutrients and energy is transferred from one organism to the other.
Therefore option (A) is correct
Question:10
Flow of energy in an ecosystem is always
(a) unidirectional
(b) bidirectional
(c) multi directional
(d) no specific direction
Answer:(a)
An ecosystem is a network of living beings related to the nonliving beings of their environment, interacting as a system. The energy enters the plants (autotrophs) through photosynthesis during the making of food. This energy is then passed on to other trophic levels in the food chain. The energy moves progressively through various trophic levels so, it may not be available to the previous level. This flow of energy is unidirectional.
Therefore option (A) is correct
Question:12
In the following groups of materials, which group (s) contains only non-biodegradable items?
(i) Wood, paper, leather
(ii) Polythene, detergent, PVC
(iii) Plastic, detergent, grass
(iv) Plastic, bakelite, DDT
(a) (iii) (b) (iv)
(c) (i) and (iii) (d) (ii) and (iv)
Answer:(d)
Substances that cannot be broken down by biological processes in nature are non- biodegradable substances, e.g., polythene, detergent, PVC, plastics, Bakelite, DDT etc. On the other hand, substances that can be broken down by biological processes are said to be biodegradable, e.g., wood, paper, leather, grass, animal bones etc.
(ii) and (iv) contains non-biodegradable items.
Therefore option (D) is correct
Question:13
Which of the following limits the number of trophic levels in a food chain?
(a) Decrease in energy at higher trophic levels
(b) Deficient food supply
(c) Polluted air
(d) Water
Answer:(a)
When we move from on trophic level to another, energy decreases. This is so because energy is lost as metabolic heat when the organisms from one trophic level are consumed by organisms of the next trophic level.
In this way, the organism at higher level gets less and less energy at progressive levels. The number of trophic levels is restricted to 3-4 because, from that point forward, the energy accessible for the following level will be too little, i.e., it will be too small to sustain life of the organisms. Hence, the decrease in energy at higher trophic levels limits the number of trophic levels in a food chain.
Therefore option (A) is correct
Question:14
Which of the statement is incorrect?
(a) All green plants and blue green algae are producers
(b) Green plants get their food from organic compounds
(c) Producers prepare their own food from inorganic compounds
(d) Plants convert solar energy into chemical energy
Answer:(b)
(a) All green plants and blue-green algae are called producers as they can prepare food from inorganic substances by photosynthesis.
(b) Green plants get their food from inorganic compounds (and not organic compounds).
(c) Producers (green plants) get their food from inorganic compounds using radiant energy of the sun in the presence of chlorophyll
(d) Producers capture the solar energy and convert it into chemical energy.
Therefore option (B) is correct
Question:15
Which group of organisms are not constituents of a food chain?
(i) Grass, lion, rabbit, wolf
(ii) Plankton, man, fish, grasshopper
(iii) Wolf, grass, snake, tiger
(iv) Frog, snake, eagle, grass, grasshopper
(a) (i) and (iii) (b) (iii) and (iv)
(c) (ii) and (iii) (d) (i) and (iv)
Ans. (c)
The flow of energy starting with one living being then onto the next at various biotic levels forms a food chain. A food chain
portrays the feeding connections between the life forms within that ecosystem.
(i) is forest food chain
Grass — Rabbit — Wolf — Lion
Lion consumes a wolf, wolf consumes a rabbit and rabbit consumes grass for energy.
(ii) is an aquatic food chain in which grasshopper cannot take part. Instead of grasshopper, Zooplankton should have been given
Plankton — Zooplankton — Fishes — Man
(iii) Wolf, snake and tiger all are carnivores. There is no herbivore to eat grass in this chain. So the initial transfer of energy is missing.
(iv) Grass - Grasshopper - Frog - Snake - Eagle, is a proper food chain.
Therefore option (C) is correct
Question:19
The decomposers in an ecosystem
(a) convert inorganic material, to simpler forms
(b) convert organic material to inorganic forms
(c) convert inorganic materials into organic compounds
(d) do not breakdown organic compounds
Answer:(b)
Decomposers feed on dead remaining parts and byproducts or living beings. These are also called as scavengers of nature/environment. The decomposers in an ecosystem convert organic material to inorganic forms, which goes into the soil and are once again used up by the plants. Examples of decomposers: Fungi, bacteria etc.
Therefore option (B) is correct
Question:20
If a grass hopper is eaten by a frog, then the energy transfer will be from
(a) producer to decomposer
(b) producer to primary consumer
(c) primary consumer to secondary consumer
(d) secondary consumer to primary consumer
Answer:(c)
The food chain involved is:
Grass – Grasshopper – Frog.
In this food chain, if a grasshopper is eaten by a frog, then the energy transfer will be from primary consumer to secondary consumer. Grasshopper feeds on producers, i.e., the grass/plants.
Level - 1 Grass Producer
Level – 2 Grasshopper Primary consumer
Level – 3 Frog Secondary consumer
Therefore option (C) is correct
Question:21
Disposable plastic plates should not be used because
(a) they are made of materials with light weight
(b) they are made of toxic materials
(c) they are made of biodegradable materials
(d) they are made of non-biodegradable materials
Answer:(d)
Disposable plastic plates should not be used because they are made of non-biodegradable material, i.e., plastic. They can cause pollution, block drains and harm animals.
Non-biodegradable materials do not get decomposed naturally or even artificially by any means. The only thing we can do with non-biodegradable material is to reduce, reuse and recycle them. So disposable plastic plates should not be used.
Therefore option (D) is correct
NCERT Exemplar Class 10 Science Solutions Chapter 15-Short Answer
Question:22
Why is improper disposal of waste a curse to environment?
Answer:
Improper disposal of waste a curse to environment. Disposal means ‘to get rid of’. Improper disposal of waste adds pollutants to the environment. It can cause harm to human, animal and plant health as it pollutes the air, water and soil. So the entire food chain is affected. Improper waste disposal often contaminates groundwater supplies, lakes, ponds, rivers etc.
Question:23
Write the common food chain of a pond ecosystem.
Answer:
Producers: Rooted or floating plants usually algae, called phytoplankton are the major autotrophs that act as the food sources to consumers.
Consumers are of two types:
Big Fish/Animals/Birds consume the small fish.
So the food chain is as follows:
Algae ---------Protozoa ———Small fish —— Large fish/bird/animal
(Producer) (Herbivore) (Carnivore) (Large carnivore)
Question:24
What are the advantages of cloth bags over plastic bags during shopping?
Answer:
Plastic bags are made of non-biodegradable material, i.e., plastic.
They can cause pollution, block drains and harm animals.
They do not get decomposed naturally or even artificially by any means.
Cloth bags have following advantages over plastics bags
These are biodegradable in nature so do not harm the environment.
They can be reused over and over again.
Question:25
Why are crop fields known as artificial ecosystems?
Answer:
An artificial ecosystem is a human-made system of plants, animals, and people living in an area together with their surroundings. These are not self-sustainable. So these are modified and managed by human beings
Examples: aquarium, botanical gardens etc.
Crop fields are man-made; plants do not grow naturally in crop fields. Most of the plants are grown by humans according to the season, type of soil, needs etc.
In crop fields, the land is managed by humans, soil is prepared for sowing seeds, constant irrigation is done to get good yield. Thus, crop field are known as artificial ecosystems
Question:26
Differentiate between biodegradable and non-biodegradable substances. Cite examples.
Answer:
Biodegradable substances | Non-biodegradable substances |
These can be broken down into simpler
substances by biological processes and
action of microorganisms | These can not be broken down into simpler substances by biological processes or by action of microorganisms |
Examples:paper,vegetable peels,leaves | Examples: DDt,polythene bags, plastics, |
They are environment friendly | They are not environment friendly |
can be recyled naturally as well as by humans | cannot be recyles |
Can produce useful products after biodegrading | These pollutes the environment |
Question:27
Suggest one word for each of the following statements/ definitions
(a) The physical and biological world where we live in
(b) Each level of food chain where transfer of energy takes place
(c) The physical factors like temperature, rainfall, wind and soil of an ecosystem
(d) Organisms which depend on the producers either directly or indirectly for food
Ans.
(a) Environment
(b) Trophic level
(c) Abiotic factors
(d) Consumers/heterotrophs
Environment: the surroundings or conditions in which a person, animal, or plant lives or operates.
Trophic Level: Each level of several hierarchical levels in an ecosystem, consisting of organisms sharing the same function in the food chain and the same nutritional relationship to the primary sources of energy.
Abiotic factors: non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems.
Heterotrophs: Organisms that depend on the producers/autotrophs either directly or indirectly for food.
Question:28
Explain the role of decomposers in the environment?
Answer:
Decomposers feed on the remains of other organisms. The organisms that feed on dead plants and animals are called decomposers, e.g., bacteria, fungi etc.
They breakdown the complex organic compounds present in the dead remains into simpler substances and obtain nutrition from them. These substances are released into the soil and the atmosphere.
Role of decomposers on the environment:
(i) Help in the recycling of materials
(ii) Help in the replenishment of the soil's nutrients
(iii)They clean up our surroundings by decomposing organisms and organic wastes
Question:29
Select the mis-matched pair in the following and correct it.
(a) Bio-magnification — Accumulation of chemicals at the successive trophic levels of a food chain
(b) Ecosystem — Biotic components of environment
(c) Aquarium — A man-made ecosystem
(d) Parasites — Organisms which obtain food from other living organisms
Answer:
(a) Bio-magnification — Accumulation of chemicals at the successive trophic levels of a food chain. Correct definition.
(b) Ecosystem — Biotic components of environment – incorrect.
Ecosystem consists of biotic components comprising living organisms and abiotic components comprising physical factors like temperature, rainfall etc.
(c) Aquarium — A man-made ecosystem – Correct.
(d) Parasites — Organisms that obtain food from other living organisms – Correct.
Therefore option (B) is correct
Question:30
We do not clean ponds or lakes, but an aquarium needs to be cleaned. Why?
Answer:
A pond or lake is a natural ecosystem. These are self-sustaining and complete. All the organisms of the food chain are available. If any organism dies, there are decomposers to decompose their bodies into simpler substances.
An artificial ecosystem is a human-made system of plants, animals, and people living in an area together with their surroundings. These are not self-sustainable.
An aquarium is an artificial and incomplete ecosystem. The abiotic components are not supplied naturally. It may not have all the biotic components in it. If a fish dies in an aquarium in the absence of a decomposer, it will lie there like a rotten body, polluting the water of the aquarium. Thus, an aquarium needs regular cleaning and maintenance.
NCERT Exemplar Class 10 Science Solutions Chapter 15-Long Answer
Question:31
Indicate the flow of energy in an ecosystem. Why is it unidirectional? Justify.
Answer:
The flow of energy in an ecosystem is unidirectional and occurs in the following sequence:
Sun —— Producer ——— Herbivore —— Carnivore
(i) Energy flows dynamically starting with one trophic level then onto the next
(ii) Energy cannot return back to a trophic level.
(iii)Out of the total energy accessible, at a particular trophic level, only 10% is given to the next trophic level.
(iv) It is impossible for energy to flow in the reverse direction
(v) The accessible energy decreases at a higher trophic level as energy moves from lower level to higher level
(vi) Part of the energy is used by an organism for its needs and the remaining part is lost in energy transfer
Question:32
What are decomposers? What will be the consequence of their absence in an ecosystem?
Answer:
Decomposers feed on the remains of other organisms. The organisms that feed on dead plants and animals are called decomposers, e.g., bacteria, fungi etc. They breakdown the complex organic compounds present in the dead remains into simpler substances and obtain nutrition from them. These substances are released into the soil and the atmosphere.
Role of decomposers on the environment:
(i)Help in the recycling of materials
(ii) Help in the replenishment of the soil's nutrients
(iii)They clean up our surroundings by decomposing organisms and organic wastes.
The outcome of their absence in an ecosystem can be disastrous as:
(i) Accumulation of dead bodies and the accumulation of non-living organisms like plant leaves, fruits, vegetables etc. would take place. This would pollute the environment.
(ii) The components by which bodies are made would never be returned to the soil if these are not decayed by the organism into smaller digestible molecules by decomposers.
Question:33
Suggest any four activities in daily life which are eco-friendly.
Answer:
Eco-friendly activities are those activities that are beneficial for the environment
Four activities in daily life that are eco-friendly are as follows:
(i) Separation of bio-degradable and non-biodegradable wastes: This is a swatch Bharat initiative, you may have noticed dustbins with the green and blue colour where green belongs to biodegradable and blue belongs to non-biodegradable.
(ii) Replace polythene/plastic bags with cloth/paper bags: many cities in Indian have banned the use of plastic.
(iii) Use of public transport or carpool for commuting, walking or using cycle for short distances, or even using electric bikes.
(iv) Using rainwater harvesting wherever possible.
(v) Switching off light/fans when not in use, using sunlight in the daytime and using power-efficient equipment.
(vi) Replacing fertilizers with compost and vermicompost to avoid insecticides or pesticides.
Question:34
Give two differences between food chain and food web.
Answer:
Food chain | Food Web |
Food chain is a series of organisms feeding on each other in an order for their nutritional requirements | A number ofinterconnected food chains involving many organisms comprises a food web |
Linear in nature with smaller animals in bottom to large animals in top | it is a computer web of food chains interlinked to each othe |
|
|
Question:35
Name the wastes which are generated in your house daily. What measures would you take for their disposal?
Ans
1. Kitchen waste like food, vegetable peel, fruits all that are biodegradable can be thrown directly in a compost pit and it turns into useful humus.
2. Papers waste like newspapers, magazines and textbooks, plastic waste like bottles, Tupperware containers should be reused or should be sent for recycling.
3. Biohazards waste like cotton, band-aid, used tampon, needles, injections should be disposed of properly in the designated waste are as they may carry disease-carrying pathogens.
4. Vegetable/fruit peels/rind should be placed near trees/plants so that on decomposition they enrich the soil with nutrients.
Question:36
Suggest suitable mechanism (s) for waste management in fertiliser industries.
Ans.
Fertiliser industries produce effluents and harmful gases as main wastes. These are artificially produced so lot of energy is consumed to make them. These are biologically less absorbable and have a bad effect on human health.
A suitable mechanism for waste management is:
(i) For control of gaseous pollutants combustion equipment’s are used for pollutants that can be oxidized. The pollutants are exposed to a high temperature (1650°C) in the process.
(ii) Air pollutants and flammable compounds are controlled through the use of adsorption equipment. Adsorption equipment tries to absorb pollutants on its surface pores and on heating the adsorbents we can release in a closed chamber and convert the harmful chemicals into less harmful chemicals.
(iii) Decrease the use of fertilizers and try to use natural manures for nutrients in the soil.
(iv) Try to have different crops in an area
(v) Leave the area for some time without any crops which helps in regaining nutrients in the soil.
Question:37
What are the by-products of fertiliser industries? How do they affect the environment?
Ans.
Fertiliser industries produce effluents and harmful gases as main wastes. These are artificially produced so a lot of energy is consumed to make them. The by-products of fertilizer industries are pesticides and some chemical fertilizers. They are non-biodegradable, so they get accumulated at each trophic level. These pesticides mix up with the soil and water. Eventually, they get absorbed by the growing plants along with water and minerals. The plants are consumed by herbivores, so the poisonous chemicals enter the bodies of these herbivores through the food chain. Next, when carnivores eat herbivores, the pesticides get transferred to their bodies.
Humans, being omnivores, eats both plants and herbivores and the fertilizers get accumulated into their body. Thus, pesticides enter the food chain at the producer level and in the process of transfer of food through food chains, they get concentrated at each trophic level. This is called bio-magnification.
Question:38
Explain some harmful effects of agricultural practices on the environment.
Answer:
Some harmful effects of agricultural practices on the environment are as follows:
(i) Soil degradation: loss of soil fertility because of extensive cropping. Some of the nutrients cannot be replaced naturally due to the high demand of the crop.
(ii) Pollution: Soil, water and air pollution caused by the use of synthetic fertilizers and pesticides. The majority of pesticides are health hazardous due to bio-magnification. The harm caused increases when we move from lower trophic levels of a food chain to higher trophic levels.
(iii) Water shortage: Excess use of groundwater for agriculture lowers the water table. This makes the underground water to go deep into the ground.
(iv) Deforestation: Indiscriminate falling of trees for agriculture has resulted in the loss of habitat for wildlife. A natural ecosystem is damaged because of this.
NCERT Exemplar Solutions Class 10 Science Chapter 15 Our Environment Important Topics:
- In this chapter, students will understand the food chain and the importance of different species and animals.
- NCERT Exemplar class 10 science solutions chapter 15 discusses how energy is distributed among the animals of food chain
- In this chapter, students will learn about ozone layer depletion and the greenhouse effect.
- In this chapter, students will also learn the problems created by excessive ultraviolet rays because of ozone layer depletion.
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Features of NCERT Exemplar Class 10 Science Solutions Chapter 15 Our Environment:
These Class 10 Science NCERT exemplar chapter 15 solutions provide an understanding of the environment around us and how organisms are sustained by this.
The chapter discusses the food chain and the importance of different species and animals which can be leveraged by the students through these solutions to understand and attempt Our Environment based application problems.
The Class 10 Science NCERT exemplar solutions chapter 15 Our Environment is sufficient to solve the questions given in books such NCERT Class 10 Science, CBSE Previous Year Question Papers.
In case the student is looking to explore these solutions in offline mode, the NCERT exemplar Class 10 Science solutions chapter 15 pdf download feature provides the material in a pdf format which can be used to resolve queries while attempting NCERT exemplar Class 10 Science chapter 15.
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