✅ True or False (10 Questions)

1. A habitat is a place that provides the right conditions for an organism to live and grow.
   True hecu112
2. Biotic components of a habitat include only animals, not plants or microorganisms.
   False
   (Biotic components include plants, animals, and microbes.) hecu112
3. Abiotic components of an ecosystem include air, water, soil, sunlight, and temperature.
   True hecu112
4. A population refers to different species living together in the same habitat.
   False
   (Population means individuals of the same species living together.) hecu112
5. A community is formed by different populations living and interacting in the same habitat.
   True hecu112
6. Food chains in an ecosystem are always independent and never connected with each other.
   False
   (Food chains interlink to form a food web.) hecu112
7. Producers are organisms that make their own food through photosynthesis.
   True hecu112
8. Decomposers help in recycling nutrients back into the soil by breaking down dead matter.
   True hecu112
9. Competition among organisms for food, space, and sunlight helps maintain balance in an ecosystem.
   True hecu112
10. Human activities like deforestation, pollution, and overuse of resources can disturb ecosystem balance.
    True

✅ Fill in the Blanks (10 Questions)

1. A __________ is the place where an organism lives and grows.
   Answer: habitat hecu112
2. Living components of a habitat are called __________ components.
   Answer: biotic hecu112
3. Non-living components like air, water, soil, and sunlight are called __________ components.
   Answer: abiotic hecu112
4. A group of organisms of the same kind living together in an area is called a __________.
   Answer: population hecu112
5. Different populations living and interacting in the same habitat form a __________.
   Answer: community hecu112
6. The interaction of biotic and abiotic components in an area forms an __________.
   Answer: ecosystem hecu112
7. Green plants are called __________ because they make their own food.
   Answer: producers hecu112
8. Organisms that depend on other organisms for food are called __________.
   Answer: consumers hecu112
9. Microorganisms like fungi and bacteria that break down dead matter are called __________.
   Answer: decomposers hecu112
10. Interconnected food chains in an ecosystem form a __________.
    Answer: food web

✅ Multiple Choice Questions (15 MCQs)

1. A habitat is best defined as:

A. A place where only animals live
B. A place that provides the right conditions for an organism
C. A place with only water bodies
D. A place without sunlight
✅ Answer: B hecu112

2. Which of the following is a biotic component?

A. Water
B. Soil
C. Fish
D. Temperature
✅ Answer: C hecu112

3. Abiotic components of a habitat include:

A. Plants and animals
B. Air, water, sunlight, temperature
C. Only microorganisms
D. Only decomposers
✅ Answer: B hecu112

4. A population refers to:

A. Different species living together
B. Only plants in a habitat
C. A group of the same kind of organisms living together
D. All abiotic components
✅ Answer: C hecu112

5. A community is formed by:

A. Only one population
B. Only abiotic components
C. Different populations living together
D. Only producers
✅ Answer: C hecu112

6. The interaction of biotic and abiotic components forms an:

A. Atmosphere
B. Ecosystem
C. Population
D. Mineral layer
✅ Answer: B hecu112

7. Which of the following is an aquatic ecosystem?

A. Forest
B. Pond
C. Desert
D. Grassland
✅ Answer: B hecu112

8. Plants are called producers because they:

A. Eat animals
B. Depend on other organisms for food
C. Make their own food by photosynthesis
D. Break down dead matter
✅ Answer: C hecu112

9. Organisms that eat only plants are called:

A. Carnivores
B. Herbivores
C. Omnivores
D. Decomposers
✅ Answer: B hecu112

10. Which organism is a decomposer?

A. Deer
B. Tiger
C. Mushroom
D. Eagle
✅ Answer: C hecu112

11. A food chain shows:

A. How plants grow
B. The sequence of “who eats whom”
C. Only abiotic interactions
D. Only human activities
✅ Answer: B hecu112

12. Interlinked food chains form a:

A. Habitat
B. Food web
C. Population
D. Decomposition cycle
✅ Answer: B hecu112

13. The process of breaking down dead matter into simpler substances is called:

A. Pollination
B. Decomposition
C. Photosynthesis
D. Competition
✅ Answer: B hecu112

14. Competition among organisms helps in:

A. Destroying habitats
B. Maintaining ecosystem balance
C. Increasing pollution
D. Stopping decomposition
✅ Answer: B hecu112

15. Which of the following human activities threatens ecosystems?

A. Conservation
B. Deforestation and pollution
C. Photosynthesis
D. Seed dispersal
✅ Answer: B

✅ Assertion–Reason Questions (10)

Directions: Choose the correct option:

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true

1.

Assertion (A): A habitat provides the right conditions for an organism to survive.
Reason (R): Organisms need food, water, air, shelter, and suitable temperature.
✅ Answer: A hecu112

2.

Assertion (A): Both pond and forest habitats contain living and non-living components.
Reason (R): Every habitat has biotic and abiotic components interacting together.
✅ Answer: A hecu112

3.

Assertion (A): A population consists of organisms of the same species living in one area.
Reason (R): Different species living together form a community, not a population.
✅ Answer: A hecu112

4.

Assertion (A): An ecosystem is formed by interactions between living and non-living components.
Reason (R): Biotic components depend on abiotic components for survival.
✅ Answer: A hecu112

5.

Assertion (A): Producers are placed at the first trophic level in a food chain.
Reason (R): Producers make their own food through photosynthesis.
✅ Answer: A hecu112

6.

Assertion (A): Decomposers are not important in an ecosystem.
Reason (R): Decomposers recycle nutrients back into the soil by breaking down dead matter.
✅ Answer: D hecu112

7.

Assertion (A): Food chains in an ecosystem are interconnected.
Reason (R): A network of interconnected food chains is called a food web.
✅ Answer: A hecu112

8.

Assertion (A): Competition among organisms helps maintain balance in an ecosystem.
Reason (R): Competition controls population size and prevents overuse of resources.
✅ Answer: A hecu112

9.

Assertion (A): Mutualism is a relationship where both organisms benefit.
Reason (R): Honeybees get nectar and flowers get pollinated.
✅ Answer: A hecu112

10.

Assertion (A): Human activities like deforestation and pollution threaten ecosystems.
Reason (R): Such activities disturb natural balance and destroy habitats.
✅ Answer: A

✅ Very Short Answer Questions (10 Questions)

(2 Marks Each – CBSE Class 8 Standard, Good Quality)

1. What is a habitat?

Answer:
A habitat is the place where an organism lives and grows. It provides food, water, shelter, and suitable conditions for survival. hecu112

2. Name two biotic components of a pond ecosystem.

Answer:
Two biotic components of a pond ecosystem are fish and algae (plants). hecu112

3. What are abiotic components? Give two examples.

Answer:
Abiotic components are non-living parts of a habitat. Examples are water and sunlight. hecu112

4. Define population in an ecosystem.

Answer:
A population is a group of organisms of the same species living in a particular area at a given time. hecu112

5. What is a community?

Answer:
A community consists of different populations of plants, animals, and microorganisms living together in the same habitat. hecu112

6. What is an ecosystem?

Answer:
An ecosystem is formed when biotic and abiotic components interact with each other in a given area. hecu112

7. Why are plants called producers?

Answer:
Plants are called producers because they make their own food by photosynthesis using sunlight, water, and carbon dioxide.

8. What is a food chain?

Answer:
A food chain is a simple sequence showing “who eats whom” in an ecosystem. hecu112

9. Who are decomposers? Give one example.

Answer:
Decomposers are organisms like fungi and bacteria that break down dead matter and recycle nutrients. Example: Mushroom.

10. Mention one way human activities can disturb ecosystems.

Answer:
Human activities such as deforestation and pollution destroy habitats and disturb the balance of ecosystems.

✅ Short Answer Questions (10 Questions)

(3 Marks Each – Good Quality CBSE Answers)

1. Differentiate between biotic and abiotic components of a habitat.

Answer:
Biotic components are the living parts of a habitat such as plants, animals, and microorganisms. Abiotic components are the non-living parts such as air, water, soil, sunlight, and temperature. Both interact to support life in an ecosystem.

2. Explain the difference between population and community.

Answer:
A population is a group of organisms of the same species living in a particular area. A community consists of different populations of various species living and interacting together in the same habitat. hecu112

3. What is an ecosystem? Why is it important?

Answer:
An ecosystem is formed when living organisms (biotic components) interact with non-living components (abiotic components) in an area. Ecosystems are important because they provide food, shelter, oxygen, and maintain balance in nature.

4. Explain the role of decomposers in an ecosystem.

Answer:
Decomposers like fungi and bacteria break down dead plants and animals into simpler substances. This process returns nutrients to the soil, helping plants grow again. Thus, decomposers recycle nutrients and prevent waste accumulation.

5. What is a food chain? Give one example.

Answer:
A food chain is a sequence showing how energy passes from one organism to another through eating. Example:
Grass → Grasshopper → Frog → Snake → Eagle

6. What is a food web? How is it different from a food chain?

Answer:
A food web is a network of interconnected food chains in an ecosystem. Unlike a food chain, which is linear, a food web shows multiple feeding relationships because organisms may have more than one food source or predator.

7. Why are producers placed at the first trophic level?

Answer:
Producers like green plants form the first trophic level because they make their own food through photosynthesis. They provide energy to all other organisms in the ecosystem directly or indirectly.

8. How does competition help maintain balance in an ecosystem?

Answer:
Competition occurs when organisms fight for food, water, space, or sunlight. It controls population size and prevents one species from growing too much. This helps maintain balance and stability in ecosystems. hecu112

9. Explain mutualism with an example.

Answer:
Mutualism is a relationship where both organisms benefit. Example: Honeybees get nectar from flowers, and flowers get pollinated, helping in seed formation.

10. How do human activities threaten ecosystems?

Answer:
Human activities like deforestation, pollution, overuse of resources, and habitat destruction disturb the balance of ecosystems. These actions reduce biodiversity and affect the survival of plants, animals, and humans.

✅ Case-Based Questions (4 Cases)

(4 Marks Each | Sub-questions: 1 + 1 + 2 Marks)
CBSE Competency-Based Standard

Case 1: Habitat and Components

A pond is a habitat where many organisms live. It contains fish, frogs, snails, algae, and ducks. Along with living organisms, the pond also has water, sunlight, soil, and oxygen. All these components interact to support life.

Questions:

Q1. (1 Mark) Name one biotic component of the pond.
Answer: Fish / Frog / Algae

Q2. (1 Mark) Name one abiotic component of the pond.
Answer: Water / Sunlight / Oxygen

Q3. (2 Marks) Why is a pond called an ecosystem?
Answer:
A pond is called an ecosystem because biotic components (plants, animals, microbes) interact with abiotic components (water, sunlight, air, soil) to support life.

Case 2: Food Chain and Food Web

In a grassland ecosystem, grass is eaten by a grasshopper. The grasshopper is eaten by a frog, and the frog is eaten by a snake. Many such food chains exist and are connected with each other.

Questions:

Q1. (1 Mark) What is the first trophic level in a food chain?
Answer: Producers (green plants like grass) hecu112

Q2. (1 Mark) Name the consumer that eats grasshopper.
Answer: Frog hecu112

Q3. (2 Marks) How is a food web different from a food chain?
Answer:
A food chain is a single linear sequence of feeding. A food web is a network of interconnected food chains showing multiple feeding relationships in an ecosystem. hecu112

Case 3: Decomposers and Recycling

In forests, dead leaves, plants, and animals are broken down by microorganisms like fungi and bacteria. Mushrooms are often seen growing on dead trees during the rainy season. This process returns nutrients back to the soil.

Questions:

Q1. (1 Mark) Name one decomposer organism.
Answer: Fungi / Bacteria / Mushroom hecu112

Q2. (1 Mark) What is the process of breaking down dead matter called?
Answer: Decomposition hecu112

Q3. (2 Marks) Why are decomposers important for an ecosystem?
Answer:
Decomposers recycle nutrients back into the soil by breaking down dead matter. This helps plants grow and keeps the environment clean.

Case 4: Ecosystem Balance and Human Impact

Elephants often enter farms when forests shrink due to deforestation and water scarcity. Human activities like cutting trees, pollution, and overuse of natural resources disturb ecosystems and create conflicts between wildlife and humans.

Questions:

Q1. (1 Mark) Why do elephants enter human farms?
Answer: Due to lack of food and water in forests hecu112

Q2. (1 Mark) Name one human activity that threatens ecosystems.
Answer: Deforestation / Pollution hecu112

Q3. (2 Marks) How can such disturbances affect ecosystem balance?
Answer:
Disturbances reduce natural habitats, disturb food chains, decrease biodiversity, and force animals into human areas, creating imbalance in ecosystems.

✅ Long Answer Questions (5 Questions)

(5 Marks Each – High-Quality CBSE Answers)

1. Explain the difference between habitat, population, community, and ecosystem.

Answer:
Nature is organised at different levels:

• Habitat: It is the place where an organism lives and gets food, water, shelter, and suitable conditions. Example: Pond or forest.
• Population: It is a group of organisms of the same species living in one habitat. Example: A group of fish in a pond.
• Community: It consists of different populations of plants, animals, and microorganisms living together in the same habitat.
• Ecosystem: It includes the community of living organisms along with non-living components like air, water, soil, sunlight, and their interactions.

Thus, an ecosystem is the largest unit that supports life in balance.

2. Describe biotic and abiotic components of an ecosystem with examples.

Answer:
An ecosystem has two main components:

Biotic Components (Living)

These include all living organisms such as:

• Plants (producers)
• Animals (consumers)
• Microorganisms like bacteria and fungi (decomposers)

Abiotic Components (Non-living)

These include physical factors such as:

• Air
• Water
• Soil
• Sunlight
• Temperature

Both biotic and abiotic components interact to support survival, growth, and reproduction of organisms.

3. Explain the importance of food chains and food webs in maintaining ecosystem balance.

Answer:
A food chain shows the transfer of energy in an ecosystem through feeding relationships. Example:
Grass → Grasshopper → Frog → Snake

A food web is a network of interconnected food chains. It shows that organisms may have multiple food sources and predators.

Food chains and food webs are important because:

• They maintain the balance of populations
• They ensure energy flow from producers to consumers
• They show interdependence among organisms

Thus, they help ecosystems remain stable and balanced. hecu112

4. What role do decomposers play in nature? Explain with examples.

Answer:
Decomposers such as fungi and bacteria break down dead plants, animals, and waste into simpler substances.

Their role includes:

• Recycling nutrients back into the soil
• Helping plants grow by enriching soil fertility
• Preventing accumulation of dead matter
• Maintaining cleanliness in nature

Example: Mushrooms growing on dead trees and bacteria decomposing animal remains.

Therefore, decomposers are essential for nutrient cycling and ecosystem balance. hecu112

5. How do human activities disturb ecosystems? Suggest measures to protect ecosystems.

Answer:
Human activities disturb ecosystems in many ways:

• Deforestation: Destroys habitats and reduces biodiversity
• Pollution: Harms air, water, soil, and organisms
• Overuse of resources: Leads to ecosystem imbalance
• Pesticides and chemicals: Reduce soil fertility and kill useful organisms
• Habitat loss: Forces animals into human settlements, causing conflicts

Measures to protect ecosystems:

• Plant and protect trees
• Reduce pollution through recycling and waste management
• Use eco-friendly farming practices
• Conserve wildlife through protected areas
• Use resources sustainably

Protecting ecosystems is necessary for the survival of all living beings, including humans.