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Class 10 Science Chapter 13 Our Environment Important Questions

Q: Q1. Why is the maximum concentration of pesticides found in human beings?

Ans: The pesticides are not biodegradable, they get accumulated progressively at each trophic level. As human beings occupy the topmost level in the food chain, their concentration becomes maximum in our bodies.

Q: Q2. Give one method which could be applied to reduce our intake of pesticides through food to some extent.

Ans: By using biological methods for controlling insects in fields and by washing fruits and vegetables before eating could help to reduce our intake of pesticides through food to some extent.

Q: Q3. Our environment is made up of various ecosystems. What is an ecosystem?

Ans: An ecosystem is defined as a structural and functional unit of the biosphere. It comprises living organisms and their nonliving environment that interact by means of food chains and biogeo-chemical cycles resulting in energy-flow, biotic diversity and material cycling to form stable self-supporting systems.

Q: Q4. Why is a lake considered to be a natural ecosystem?

Ans: Lake is an ecosystem where living organisms grow, reproduce and interact among each other as well as with abiotic components and carry out other activities in nature by themselves without any human interference, therefore it is referred to as a natural ecosystem.

Q: Q5. List two biotic components of a biosphere.

Ans: Two biotic components of a biosphere are: (i) Producers – Include organisms which can produce their food using simple inorganic compounds, e.g., all green plants, blue green algae (cyanobacteria). (ii) Consumers – Include organisms which are unable to synthesise their food, therefore, utilise materials and energy stored by the producers or eat other organisms, e.g., all the animals.

Here are some critical Chapter 13 Our Environment Problems for Class 10 Science. These inquiries are intended to aid students in studying for and performing well on the CBSE Class 10 Science Examination 2024–25. Students can clear up their concerns and be ready for the exams by practising different types of questions. By answering these questions, you’ll increase your confidence while also sharpening your problem-solving abilities

Table of Contents

Introduction

In Chapter 13, “Our Environment,” of Class 10 Science, students embark on a journey to understand the delicate balance of ecosystems. This chapter delves into the components that constitute an ecosystem, shedding light on the intricate interplay of living and non-living entities. Moreover, it scrutinizes various human activities that impact the environment, fostering awareness about our role in safeguarding the delicate ecological equilibrium for a sustainable future.

Chapter 13 Our Environment Important Questions and Answers

Q 1. If a grasshopper is eaten by a frog, then the energy transfer will be from:

Options

(a) Producer to decomposer
(b) Producer to consumer
(c) Primary consumer to secondary consumer
(d) Secondary consumer to primary consumer

Ans. (c)

Explanation:
Grasshoppers feed on grass (producers) and are thus classified as primary consumers. When a frog eats a grasshopper, the energy transfer happens from the primary consumer (grasshopper) to the secondary consumer (frog).

Q 2. The decomposers in an ecosystem

Options

(a) Convert dead organisms into fossil fuels
(b) Convert organic material to inorganic forms
(c) Convert inorganic materials into organic compounds
(d) Do not break down organic compounds

Ans. (b)

Explanation:
Decomposers, such as bacteria and fungi, break down dead plants and animals, converting organic matter into inorganic substances like nutrients (e.g., nitrogen, phosphorus) that are released into the environment. This process recycles essential nutrients back into the ecosystem.

Q 3. Why do vegetarian habits help us in getting more energy? In terms of energy, who is at an advantageous position (vegetarian or a nonvegetarian) and Why?

Explanation:
Vegetarians are at an advantageous position in terms of energy because they obtain food directly from plants, which are producers in the food chain. According to the 10% energy transfer rule in ecology, only about 10% of the energy from one trophic level is passed on to the next level. For example, when herbivores (primary consumers) feed on plants (producers), they receive 10% of the energy stored in plants (e.g., if the plant provides 100 J, the herbivore gets 10 J). Non-vegetarians who eat herbivores (secondary consumers) receive only 10% of the energy from the herbivore (e.g., 1 J from the original 10 J). Thus, vegetarians, by eating directly from the plants, obtain more energy (e.g., 100 J) compared to non-vegetarians who only get a fraction of that energy (e.g., 1 J). This makes vegetarians more energy-efficient in the food chain.

Q 4. Answer the following questions:

(a) What is the energy pyramid? Why is it broader at base and narrower at the apex region?

(b) When plants are eaten by primary consumers a great deal of energy is lost as heat to the environment and some amount goes into carrying out various life processes. State the average percentage of energy lost in this manner.

Explanation:
(a) An energy pyramid is a graphical representation of the flow of energy from the producers through the various consumers. It shows the amount of energy available and the loss of useful energy at each step of the food chain in an ecosystem. As the energy gets transferred from lower trophic level to the higher one, there is a loss of large amounts of energy due to metabolism and heat. As a result very little energy (i.e., 10%) gets transferred to the next level. So the trophic level at the base has maximum energy and that at the top has the least amount of energy. Hence the energy pyramid is broader at the base and narrower at the top.
(b) The average percentage of energy lost when plants are eaten by primary consumers is 90%.

Q 5. (a) Write the percentage of (i) solar energy captured by the autotrophs and (ii) energy transferred from autotrophs to the next level in a food chain.

(b) What are trophic levels? Why do different food chains in an ecosystem not have more than four to five trophic levels ? Give a reason.

Explanation:
(a) (i) Plants capture only about 1% of the solar energy that falls on them and use it for photosynthesis.
(ii) On average, only about 10 % of energy stored as biomass in a trophic level is passed from one level to the next. This is known as “10 percent rule” and it limits the number of trophic levels an ecosystem can support.
(b) Trophic levels refer to the different stages in a food chain where energy is transferred from one organism to another. Organisms are grouped based on their role in the ecosystem, such as producers (first trophic level), consumers (herbivores, carnivores, etc.), and decomposers (last trophic level).
There is only 10% flow of energy from one trophic level to the next higher level. The loss of energy at each step is so great that very little usable remains after four or five trophic levels. Hence only 4 to 5 trophic levels are present in each food chain.

CBSE Class 10 Science Chapter wise Important Questions

Chapter No.	Chapter Name
Chapter 1	Chemical Reactions and Equations
Chapter 2	Acid, Bases and Salts
Chapter 3	Metals and Non-Metals
Chapter 4	Carbon and its Compounds
Chapter 5	Life Processes
Chapter 6	Control and Coordination
Chapter 7	How do Organisms Reproduce
Chapter 8	Heredity
Chapter 9	Light : Reflection and Refraction
Chapter 10	The Human Eye and the Colourful world
Chapter 11	Electricity
Chapter 12	Magnetic Effects of Electric Current
Chapter 13	Our Environment

Conclusion

oswal.io offers a thorough set of questions for learning the topic in a better way if you’re looking to further practise and improve your grasp of the concepts covered in the chapter.

Frequently Asked Questions

Q1. Why is the maximum concentration of pesticides found in human beings?

Ans: The pesticides are not biodegradable, they get accumulated progressively at each trophic level. As human beings occupy the topmost level in the food chain, their concentration becomes maximum in our bodies.

Q2. Give one method which could be applied to reduce our intake of pesticides through food to some extent.

Ans: By using biological methods for controlling insects in fields and by washing fruits and vegetables before eating could help to reduce our intake of pesticides through food to some extent.

Q3. Our environment is made up of various ecosystems. What is an ecosystem?

Ans:An ecosystem is defined as a structural and functional unit of the biosphere. It comprises living organisms and their nonliving environment that interact by means of food chains and biogeo-chemical cycles resulting in energy-flow, biotic diversity and material cycling to form stable self-supporting systems.

Q4. Why is a lake considered to be a natural ecosystem?

Ans: Lake is an ecosystem where living organisms grow, reproduce and interact among each other as well as with abiotic components and carry out other activities in nature by themselves without any human interference, therefore it is referred to as a natural ecosystem.

Q5. List two biotic components of a biosphere.

Ans: Two biotic components of a biosphere are: (i) Producers – Include organisms which can produce their food using simple inorganic compounds, e.g., all green plants, blue green algae (cyanobacteria). (ii) Consumers – Include organisms which are unable to synthesise their food, therefore, utilise materials and energy stored by the producers or eat other organisms, e.g., all the animals.

Chapter Wise Important Questions for CBSE Board Class 10 Science
Chemical Reactions and Equations
Acid, Bases and Salts
Metals and Non-Metals
Carbon and its Compounds
Life Processes
Control and Coordination
How do Organisms Reproduce
Heredity
Light : Reflection and Refraction
The Human Eye and the Colourful world
Electricity
Magnetic Effects of Electric Current
Our Environment

Class 10 Science Chapter 13 Our Environment Important Questions

Introduction

Chapter 13 Our Environment Important Questions and Answers

Q 1. If a grasshopper is eaten by a frog, then the energy transfer will be from:

Options

(a) Producer to decomposer (b) Producer to consumer (c) Primary consumer to secondary consumer (d) Secondary consumer to primary consumer

Q 2. The decomposers in an ecosystem

Options

(a) Convert dead organisms into fossil fuels (b) Convert organic material to inorganic forms (c) Convert inorganic materials into organic compounds (d) Do not break down organic compounds

Q 3. Why do vegetarian habits help us in getting more energy? In terms of energy, who is at an advantageous position (vegetarian or a nonvegetarian) and Why?

Q 4. Answer the following questions:

(a) What is the energy pyramid? Why is it broader at base and narrower at the apex region?

(b) When plants are eaten by primary consumers a great deal of energy is lost as heat to the environment and some amount goes into carrying out various life processes. State the average percentage of energy lost in this manner.

Q 5. (a) Write the percentage of (i) solar energy captured by the autotrophs and (ii) energy transferred from autotrophs to the next level in a food chain.

(b) What are trophic levels? Why do different food chains in an ecosystem not have more than four to five trophic levels ? Give a reason.

CBSE Class 10 Science Chapter wise Important Questions

Conclusion

Frequently Asked Questions

Q1. Why is the maximum concentration of pesticides found in human beings?

Q2. Give one method which could be applied to reduce our intake of pesticides through food to some extent.

Q3. Our environment is made up of various ecosystems. What is an ecosystem?

Q4. Why is a lake considered to be a natural ecosystem?

Q5. List two biotic components of a biosphere.

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(a) Producer to decomposer
(b) Producer to consumer
(c) Primary consumer to secondary consumer
(d) Secondary consumer to primary consumer

(a) Convert dead organisms into fossil fuels
(b) Convert organic material to inorganic forms
(c) Convert inorganic materials into organic compounds
(d) Do not break down organic compounds