10th Our Environment CBSE Board solved Questions

Class 10 our environment board solved Questions 2016

1. What is the function of ozone in upper atmosphere?

Ans: It shields the surface of the earth from ultraviolet rays from the Sun.

2. Why should biodegradable and non biodegradable waste be discarded in two separate dustbins?
Ans: So that the time and energy required in segregation may be saved and waste may be disposed off quickly

3. The following organisms form a food chain. Which of these will have the highest concentration of non-biodegradable chemicals ? Name the phenomenon associated with it. Insects, Hawk, Grass, Snake, Frog.
Ans: Hawk ; Biomagnifications

4.. Write the full name of the group of compounds mainly responsible for the depletion of ozone layer.

Ans: Chloroflurocarbons

5. List two examples of natural ecosystem.
Ans: Forests ,Ponds,Lakes

6. Differentiate between biodegradable and non-biodegradable substances with the help of one example each.
List two changes in habit that people must adopt to dispose non-biodegradable waste, for saving the environment.

Ans: Biodegradable substances – Any substance that can be broken down into simpler substances by biological process is called biodegradable. Ex. – Human Excreta/ Vegetable peels, etc.

Non-biodegradable substances – Any substance that can can’t be broken down into simpler substances by nature or decomposers. Ex. – Plastic/ glass (or any other) (any one)

Habits that people must adopt to dispose non-biodegradable waste, for saving the environment:

- Use of separate dustbins for biodegradable and non biodegradable waste,

- Reuse of things such as poly-bags, etc.,

- Recycle of waste

- Use of cotton /jute bags for carrying vegetables

7. What will be the amount of energy available to the organisms of the 2nd trophic level of a food chain, if the energy available at the first tropic level is 10,000 joules?

Ans: 10% of 10,000 joules = 1000 J

8. ‘‘Energy flow in food chains is always unidirectional.’’ Justify this statement.

Explain how the pesticides enter a food chain and subsequently get into our body.
Ans: The flow of energy is unidirectional. The energy that is captured by the autotrophs does not revert back to the solar input and the energy which passes to the herbivores does not come back to autotrophs.

Therefore, in food chain the energy moves progressively through the various trophic levels it is no longer available to the previous level. Thus, The flow of energy in food chain is unidirectional.

The pesticides enter a food chain and subsequently get into our body in following way:

(i) Pesticides used for crop protection when washed away into the soil or water bodies absorbed by plants.

(ii) On consumption they enter our food chain and being non – biodegradable these chemicals get accumulated progressively and enter our body.

9. What is ozone ? How and where is it formed in the atmosphere? Explain how does it affect an ecosystem.

Ans: Ozone (O3) is a molecule formed by three atoms of oxygen.

Ozone is formed at at the higher levels of the atmosphere by action of UV radiation on oxygen (O2) molecule.

The higher energy UV radiations split apart some moleculer oxygen (O2) into free oxygen (O) atoms. These atoms then combine with the molecular oxygen to form ozone as shown—

O2 ⎯⎯UV⎯→ O + O then, O + O2 ⎯⎯⎯→ O3 (Ozone)

Ozone shields the surface of the earth from ultraviolet (UV) radiation from the Sun. This radiation is highly damaging to organisms, for example, it is known to cause skin cancer in human beings.

10. Construct an aquatic food chain showing four trophic levels.

Ans: Hydrilla →Scorpio→ Fish → Crane

11. To protect the food plants from insects, an insecticide was sprayed in small amounts but it was detected in high concentration in human beings. How did it happen?

Ans: As insecticides are not degradable, these get accumulated progressively at each tropic level. As human beings occupy the top level in any food chain, the high concentration of insecticide gets accumulated in their bodies. This phenomenon is known as biological magnification

12. Why do most food chains have 3- 4 steps only?
Ans: The loss of energy at each step is so great that very little usable energy remains after four trophic levels. Therefore, food chains generally consist of only three or four steps.

13. What will be impact on ecosystem if bacteria and fungi are removed from the Environment?
Ans: The decomposers bacteria and fungi secrete enzymes that breakdown organic remains into simpler soluble substances that are absorbed by saprophytes. They clean the earth from organic matter hence Environmental pollution created and food chain disturbed if bacteria and fungi are removed from the Environment.

14. Why is a pond self sustaining unit while an aquarium may not be?
Ans: A pond contains microorganisms that break-down the dead remains and waste products of organisms into simple inorganic substances that are used by other organism.

Since, pond is a natural ecosystem while an aquarium is created by man and is artificial, thus a pond self sustaining while an aquarium may not be.

15. Which level shows the maximum biological magnification? Why?
Ans: The top tropic level in any food chain has the maximum concentration of chemicals. From the soil, these are absorbed by the plants along with water and minerals, and from the water bodies these are taken up by plants and animals.


CBSE HIGHER ORDER THINKING SKILLS (HOTS) QUESTIONS :

10th Our Environment CBSEHOTS Questions

1) Write any two ways of energy flow through an ecosystem.

2) Differentiate between biodegradable and non biodegradable with respect to the effect of biological processes on them and the way they affect our environment.

3) Which level shows the maximum biological magnification? Why?

4) Why is a pond self sustaining unit while an aquarium may not be? Justify the answer.

5) Arrange grasshopper, frog, grass, eagle and snake in the form of food chain.

6) If 1000 KJ energy is available at producer level, how much energy will be available at first carnival level?

7) Why do most food chains have 3-5 steps only?

8) Select the biodegradable items from the list given below-

Polythene bags, old clothes, wilted flowers, pencil shavings, glass bangles, bronze statue, vegetable peels.

9) What will be impact on ecosystem if bacteria and fungi are removed from the Environment?

10) Express your feelings on the picture given down below. What will happen if all? Carnivores are eliminated from the environment? What measures will you take to save? Tiger?

Further Study Links by JSUNIL

10th Science – Chapter: Our Environment (Physics)
10th Science - Our Environment: Summative assignments	View/Read
10th Chapter: Our Environment Questions Paper for FA-III	View/Read
10th Science: Chapter: Our Environment HOTS Questions	View/Read
10th Chapter: Our Environment: Gist of Lesson	View/Read

CBSE CH. 10 OUR ENVIRONMENT SOLVED GUESS PAPER

CHAPTER-10 OUR ENVIRONMENT:  CBSE SOLVED GUESS PAPER

1 Marks Questions: [5]

1. Which of the following organism is likely to have maximum concentration of DDT :

Algae, fish, water flea, frog, bird

2. What is the role of bacteria and fungi in an ecosystem?

3. What are trophic levels?

4. How much energy is transferred to the next trophic level in a food chain?

5. Which trophic level has the highest concentration of toxic substances in a food chain?

Two marks questions [10]

6. Mention some sources of CFC‘s.

7. Distinguish between a food chain & a food web

8. What would happen if there are no decomposers on earth?

9. What is a food chain? Write a five step food chain found in grass land with frog as one of the members. 
What will happen to organisms at different trophic levels if all the frogs are removed?

10. The number of malaria patients increased tremendously when a large number of frogs were exported 
from the village .What could be the cause for it? Explain with the help of a food chain.

Three marks questions [15]

11. What are the problems caused by the non-biodegradable wastes that we generate?

12. Food chains generally consist of only 3 or 4 trophic levels. Why is it so?

13.  Observe the food chain  Plant (1000 kJ) --- >Goat  ---> Lion

(a) If autographs occupying the first trophic level are called producers what are herbivores Called as?

(b) How much energy does the lion get in the above food chain?

14. Vegetarian or non vegetarian food habit help us in getting more energy. Why?

15. How is ozone formed in the upper atmosphere? Why is the damage of ozone layer a cause

of concern to us? State cause of this damage.

To download Answer Visit : JSUNIL TUTORIAL 

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GIST OF THE LESSON

10th Science - Our Environment Questions Banks for CBSE Board with Hint

        Chapter - 15 Our Environment           
             Questions Paper Set-1                   

1 mark Questions:-

1. Write any one significance of biochemical 
cycles?

2. Define environment.

3. According to the sustenance from 
environment, organisms can be grouped into 
which three categories?

4. Name any two groups of producers.

5. Define consumers.

6. Write the two raw materials for making food, used by living organisms of first tropic level.

7. Explicate the principle of food web.

8. Which of the following are more numerous in a food chain:–

(i) Secondary consumer (ii) Tertiary consumer

9. Define biological magnification.

10. Write the names of two decomposers.

11. Define global warming.

12. Write one ill effect of exposure to ultraviolet rays.

13. Which component of sunlight is vital for formation of ozone?

14. As a step to control pollution ‘Kulhads’ were used on a large scale. What was the ill effect  of this practice?

15. A food chain consists of grass, lion and rabbit. In this food chain, which organism will  transfer maximum energy?

16. Which of the following are Biodegradable; plastic toys, cow dung, aluminum foil and  cotton?

17. Name the programme that froze CFC production in 1986.

18. Expand UNEP.

19. Which is greater – energy lost to the environment or energy transferred to next trophic level?

20. Write a common feature between a food chain and energy flow in nature.

21. How is packaging related to increase in non biodegradable waste?

22. Burning the coal yields energy, but if try to eat coal we will not get any energy. Why?

2 Marks Questions:-

10th Our Environment Questions foe FA-III

Very short answer questions: Each question carries 1 mark. Tick the correct one

1. Ozone layer is destroyed by

a) SO2 b) Smog c) CFC d) CO2

2. Which of the following is biodegradable?

a) Cow dung b) Plastic c) DDT d) Radioactive wastes

3. Vegetable peels, waste paper, wood carvings and egg shells can be used to make

a) Bricks b) Compost c) Urea d) None of these

4. Which of the following is constituent of a food chain?

a) Grass, wheat and mango b) Grass, goat and human

c) Goat, cow and elephant d) Grass, fish and goat

5. Acid rain is caused by precipitation of

a) Oxides of sulphur b) CFCs c) Ozone d) CO2

SHORT ANSER QUESTIONS: EACH QUESTION CARRIES TWO MARKS:

1) Classify the following as decomposers and producers -

Green plants, bacteria, fungi, algae, blue green algae.

2) Distinguish between producers and consumers.

3) Name two environment friendly practices.

ANSWER THE FOLLOWING QUESTIONS: EACH QUESTION CARRIES THREE MARKS:

1. How is ozone depletion caused? Name the compounds causing it.

2. What is meant by biodegradable waste? Which of the following are biodegradable?

Agriculture residue, plastic, insecticides, sewage.

3. What is being done to avoid ozone depletion? ( Three steps)

4. What is meant by a trophic level? Why do we have a greater number of organisms at lower levels?

Long answer (5 marks):

5. Describe any five modes of disposal of wastes.

6. Quiz:

1. Ozone layer is destroyed by ____________.

2. Ecology is the study of the interaction of _______ with each other and their surroundings.

3. Decomposers are also called ___________.

4. Water, air, light and temperature are the examples of ____ components.

5. Consumers ______manufacture their own food and depend on plants and other animals for their feed.

10th Science – Chapter: Our Environment (Physics)
10th Science - Our Environment: Summative assignments	View/Read
10th Chapter: Our Environment Questions Paper for FA-III	View/Read
10th Science: Chapter: Our Environment HOTS Questions	View/Read
10th Chapter: Our Environment: Gist of Lesson	View/Read

10th physics Chapter - 15 Our Environment POINTS TO REMEMBER

POINTS TO REMEMBER:

1) ECOLOGY – The study of the interaction of living organisms with each other and their surroundings is called ecology.

2) ENVIRONMENT – Everything that surrounds organisms and influences its life.

a) Biotic components of environment --- The living organisms .e.g. Plants and animals.

b) Abiotic components of environment --- The nonliving components  like water, air, light, etc.

It is the sum total of all external conditions and influences that affect the life and the development of organisms i.e.,it includes all the biotic and abiotic factors.

3) ECOSYSTEM – All interacting organisms in an area together with the nonliving constituents of environment. (Functional unit of an environment)

Functions of ecosystem:-

a) Flow of energy         b) Cycling of nutrients(bio-geo chemical cycles).

4) PRODUCERS --- They make the energy from sunlight available to the rest of the ecosystem.

5) CONSUMERS --- Animals can not manufacture their own food. They are called consumers.

6) BIODEGRABLE ---- Substances that are broken down by the action of bacteria or other saprophytes. e.g. – Paper.

7) NONBIODEGRABLE --- Substances that are not broken down by the action of bacteria or saprophytes. e. g. Plastic.

8) FOOD CHAIN -The process of one organism eating the other. 

GRASS-- > GRASSHOPPER-- >; FROG -> SNAKE

Importance of food chain

1.It helps in transfer of food energy from one organism to another.

2.It is a pathway for the flow of energy.

3. It helps in understanding the interdependence amongst different organisms.

Trophic levels are the various steps in the food chain .

Producers --- first trophic level                   Herbivores --- second trophic levels

Carnivores --- third trophic level               Top carnivores --- fourth trophic level

9) FOODWEB ----- It is a network of food links between populations in a community.

10) FLOW OF ENERGY -Ten percent law Energy available at each successive trophic level is 10 % of the previous level. (Lindeman 1942)

The law states that, “ only a 10 % amount of the total available energy is transferred from one trophic level to the next. The rest 90% of energy is used up or lost to the surrounding.”

11) BIOLOGICAL MAGNIFICATION --- Progressive accumulation of non- biodegradable waste at various trophic levels of food chain.

12. Differences between food chain & food web 

Food chain

1. The process of eating & being eaten to transfer food energy.  2. It forms a part of food web.

3. It has limited populations.

Food web

1. It is a system of interconnected food chains. 2. It contains many food chains.

3. It has several populations of different species.

13. HOW DO OUR ACTIVITIES AFFECT THE ENVIRONMENT?

Two major problems:-

a) Depletion of ozone layer

b) Disposal of waste

Good ozone and bad ozone

The thick blanket of ozone layer in the atmosphere which forms a protective cover & prevents UV radiation from reaching the earth‘s surface. This is called good ozone and is found in the stratosphere.

Ozone when present in the troposphere act as a pollutant . This harmful ozone is called bad ozone.

14. Depletion of ozone layer : The ozone layer protects all the organisms from the harmful ultra violet rays.

Ozone depleting substances: CFCs, N2O, CH4 , CCl4

These chlorine containing compounds are used in:  Aerosols, solvents, refrigerants and fire extinguishers.  Ozone hole developed over Antarctica.

15. Effects of ozone depletion on human health- Due to depletion of ozone layer UV radiations reaches the earth and cause:

i) skin cancer            ii) increased chances of cataract 

 iii) suppression of immune system . Managing the garbage we produce

16. Reasons for large production of garbage

i) Improvement in life style

ii) Changes in attitude (more things become disposable)

iii) Population explosion

iv) Changes in packaging (non -biodegradable)

10th Science – Chapter: Our Environment (Physics)
10th Science - Our Environment: Summative assignments	View/Read
10th Chapter: Our Environment Questions Paper for FA-III	View/Read
10th Science: Chapter: Our Environment HOTS Questions	View/Read
10th Chapter: Our Environment: Gist of Lesson	View/Read