KSEEB Solutions for Class 10 Science Chapter 15 Our Environment

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Karnataka State Syllabus Class 10 Science Chapter 15 Our Environment

KSEEB Class 10 Science Our Environment Intext Questions and Answers

Question 1.
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
Answer:
Each step or level of the food chain forms a trophic level.
Example for a food chain:

Question 2.
What is the role of decomposers in the ecosystem?
Answer:
The main role of decomposes in the ecosystem is to breakdown dead organic material and return it back to the environment. This means they play a vital role in nutrient cycles. They keep the environment clean and would not let the pile-up of biodegradable wastes.

KSEEB Class 10 science Our Environment Textbook Exercise Questions and Answers

Question 1.
Which of the following groups contain only biodegradable items?
(a) Grass, flowers and leather
(b) Grass, wood and plastic
(c) Fruit-peels, cake and lime-juice
(d) Cake, wood and grass
Answer:
(c) Fruit-peels, cake and lime-juice

Question 2.
Which of the following constitute a food-chain?
(a) Grass, wheat and mango
(b) Grass, goat and human
(c) Goat, cow and elephant
(d) Grass, fish and goat
Answer:
(b) Grass, goat and human

Question 3.
Which of the following are environment-friendly practices?
(a) Carrying cloth-bags to put .purchases in while shopping
(b) Switching off unnecessary lights and fans
(c) Walking to school instead of getting your mother to drop you on her scooter
(d) All of the above.
Answer:
(d) All of the above.

Question 4.
What will happen if we kill all the organisms in one trophic level?
Answer:
In the trophic levels, flow of energy take place from one level to another. If we kill all the organisms in one trophic level, there is imbalance in the environment which causes many ill effects.

Question 5.
Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
Answer:
The impact of removing all the organisms in a trophic level be different for different trophic levels. Because if there are no producers no food is available to any organism. There is a deficiency of energy and creates an imbalance in nature.

Question 6.
What is the biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Answer:

• Biomagnification refers to increase in concentration of a toxicant at successive trophic levels.
• Levels of this magnification would increase as the trophic level increases and would be higher for higher trophic levels.

Question 7.
What are the problems caused by the non-biodegradable wastes that we generate?
Answer:
Non-biodegradable wastes pollute the environment. They are-

1. By these – wastes Biomagnification takes place.
2. By these wastes, a large number of microbes are collected.
3. By consuming such food we get many diseases.

Question 8.
If all the waste we generate is biodegradable, will this have no impact on the environment?
Answer:
Production of bio-degradable waste will also affect the environment adversely. Excess of the garbage when decomposed, harmful gases are released causing pollution.

Question 9.
Why is damage to the ozone layer cause for concern? What steps are being taken to limit this damage?
Answer:

• Ozone layer acts as a shield absorbing highly injurious ultra violet radiation from the sun. If ozone is damaged, UV radiations reach the earth causing serious problems to living organisms. Hence ozone depletion is a cause for concern.
• In 1987, the united nations Environment programme succeeded in forging an agreement to freeze ozone depleting substances like CFCs’ production.

KSEEB Class 10 Science Our Environment Additional Questions and Answers

Question 1.
Saprophytes cannot breakdown materials like
a) Plastics
b) Vegetable peels
c) leather
d) Dead insect
Answer:
a) Plastics

Question 2.
A rat feeding on potato tuber is a
a) Producer
b) Primary consumer
c) Carnivore
d) Decomposer
Answer:
b) Primary consumer

Question 3.
An aquarium is an example for
a) A natural biome
b) An artificial ecosystem
c ) natural aquatic ecosystem
d) a community
Answer:
b) An artificial ecosystem

Question 4.
The biological process that initiates the food chain in an ecosystem is
a) respiration
b) Photosynthesis
c) Feeding activity
d) Decomposition.
Answer:
b) Photosynthesis

Question 5.
Give an example for an organism that can behave as a primary consumer as well as a secondary consumer.
Answer:
A sparrow eating grain is a herbivore, but the same sparrow when feeds on worms or tiny insects it is a secondary consumer (carnivore/predator)

Question 6.
Why are some substances biodegradable and some non-biodegradable?
Answer:

• Substances which can be broken down by the help of enzymes secreted by the bacteria and fungi (decomposers) over a period of time are biodegradable.
• Certain inert substances that cannot be broken down by the enzymes of decomposers remain in the environment for a long time. Such substances are non-biodegradable.

Question 7.
Give any two ways in which biodegradable substances would affect the environment.
Answer:

• Long term exposure to air. Light and water can cause non-biodegradable substances like plastic to emit toxic pollutants.
• They may cause bio-magnification in the food chain that may end up in humans. Ex: Minamata disease

Question 8.
Give two examples for Biogeochemical cycles.
Answer:
Carbon cycle and phosphorus cycle.

Question 9.
What is ozone and how does it affect any ecosystem?
Answer:
Ozone is a molecule formed by three atoms of oxygen. At higher levels of the atmosphere, ozone shields the surface of the earth from ultraviolet radiation from the sun. This radiation is highly damaging to organisms.

Question 10.
How can you help in reducing the problem of waste disposal? Give any two methods.
Answer:

• Minimizing the use of non- biodegradable wastes like Plastic.
• Utilising the biodegradable wastes 6. to produce biogas and compost.

Question 11.
What are the harmful effects of UV radiation?
Answer:

• UV radiation are known to cause skin cancer in human beings. UV radiation damage DNA and mutation may occur.
• They also cause cataract, inflammation of cornea… etc.

Question 12.
How is ozone formed?
Answer:
At the higher levels of the atmosphere, the higher energy UV radiations split apart some molecular oxygen into free oxygen atoms. These atoms then combine with the molecular oxygen to form ozone.

Question 13.
Which chemicals are known, to cause ozone depletion?
Answer:
Chlorofluorocarbons which are used as refrigerants and in fire extinguishers cause severe ozone depletion.

Question 14.
Expand CFC
Answer:
Chlorofluorocarbons.

Question 15.
Population explosion of human beings affects environment adversely justify.
Answer:
Increased population means increase in the demand for living space. Food and other human needs. Forests are destroyed due to urbanisation and conversion of land for agriculture. Usage of fossil fuels, industrialization, generation of garbage, sewage contribute to environment destruction

Question 16.
Why could not kulhads become a successful alternative to plastic cups?
Answer:
Kulhads, the clay made cups could not replace plastic cups completely because making of these kulhads on a large scale would result in the loss of the fertile top soil.

Question 17.
What is an ecosystem?
Answer:
An ecosystem is a functional unit of nature where living organisms interact among themselves and also with the surrounding physical environment.

Question 18.
Give few examples for artificial ecosystems.
Answer:
Gardens, crop fields and aquariums.

Question 19.
What are producers? Why are they important in an ecosystem?
Answer:
Blue Green algae and all the plants which can produce food by photosynthesis are called producers. They are the source of food to remaining group of animals (consumers). Hence producer community forms a base to all kinds of ecosystems.

Question 20.
State 10% law.
Answer:
10% law states that only 10% of the energy is transferred to each trophic level from the lower trophic level.

Question 21.
Define Foodweb?
Answer:
Natural interconnected matrix of food chains is called food web.

Question 22.
Mention few’ examples for decomposers in an ecosystem.
Answer:
Ex: Bacteria, fungi, earthworms, soil mites.

Question 23.
Why is food chain having two trophic levels most advantageous in terms of energy?
Answer:
Maximum energy is transferred from producers td herbivores. Loss of energy as heat is least.

Question 24.
In the given food chain, if plants provide 3000 J of energy to butterfly, how much energy will be available to the ultimate predator.
(Nectar)
Plant → butterfly → praying mantis → Garden lizard → owl
Answer:

As per the 10% law of transfer of energy through the trophic level, owl gets 3 J of energy.

Question 25.
The second trophic level in a lake is
(a) Phytoplankton
(b) Benthos
(c) zooplankton
(d) Fishes
Answer:
(c) zooplankton