Question 1

How might the loss of forest cover and changes in rainfall patterns lead elephants to enter human farms and villages? (Page 190)

Accepted Answer

Loss of forest cover reduces vegetation and habitat space, while changes in rainfall patterns can dry up waterholes, making food and water scarce in elephants’ natural habitats. As a result, elephants wander into nearby farms and villages in search of crops like bananas and sugarcane, leading to crop damage and potential harm to humans and animals.

Question 2

Imagine you are a tree in a dense forest. What kind of relationships would you have with water, sunlight, other animals, and other components of the forest? (Page 190)

Accepted Answer

As a tree, I would:
Water: Absorb water from the soil for photosynthesis and growth.
Sunlight: Use sunlight to produce food via photosynthesis.
Other Animals: Provide shelter, food (fruits, leaves), and oxygen for animals; animals like birds and insects aid in pollination and seed dispersal.
Other Components: Interact with soil for nutrients and stability, contribute to air quality by releasing oxygen, and help retain soil moisture to prevent erosion.

Question 3

Do you think the Earth can thrive without humans? Can humans survive without the Earth? (Page 190)

Accepted Answer

Earth without humans: Yes, Earth can thrive without humans. Ecosystems, such as forests and aquatic systems, function through natural interactions (e.g., food chains, nutrient cycling) without human intervention. Protected areas like national parks show ecosystems can self-sustain.
Humans without Earth: No, humans cannot survive without Earth, as they depend on ecosystems for air, water, food, and resources essential for survival.

Question 4

If two kinds of birds compete for the same fruit, how might their way of living change over time? (Page 190)

Accepted Answer

Competition may lead to niche differentiation, where one bird species adapts to feed at different times or on different parts of the fruit tree to reduce competition. Over time, they may evolve distinct beak shapes or feeding behaviours, or one species may dominate, forcing the other to find alternative food sources or habitats.

Question 5

Can human actions cause natural disasters? (Page 190)

Accepted Answer

Human actions can exacerbate or trigger events that resemble natural disasters. For example, deforestation and pollution can worsen floods or storms by destabilising soil and altering weather patterns. Overuse of pesticides can disrupt ecosystems, indirectly contributing to environmental imbalances.
NCERT Class 8 Science Chapter 12 Question Answer How Nature Works in Harmony (Exercise)
Keep the Curiosity Alive (Pages 207-208)

Question 6

Why is it not possible to have an ecosystem with only producers and no consumers or decomposers?

Accepted Answer

An ecosystem needs consumers to regulate producer populations (e.g., herbivores eat plants) and decomposers to recycle dead matter into nutrients for producers. Without consumers, producers would overgrow and die from competition; without decomposers, nutrients would not cycle, collapsing the system.

Question 7

Observe two different places near your home or school (e.g., a park and a roadside). List the living and non¬living components you see. How are the two ecosystems different?

Accepted Answer

We can see some common things near our home and school, such as
Park: Living (trees, birds, squirrels, grass); Non-living (soil, water, benches, sunlight).
Roadside: Living (weeds, insects); Non-living (asphalt, dust, car exhaust).
Differences: The park is a designed ecosystem with diverse plants and animals, supported by soil and water, while the roadside is a disturbed, human-altered area with fewer species and more pollution.

Question 8

‘Human-made ecosystems like agricultural fields are necessary, but they must be made sustainable.’ Comment on the statement.

Accepted Answer

Agree. Agricultural fields provide food but often use unsustainable practices (e.g., synthetic fertilisers, monoculture) that degrade soil and harm biodiversity. Sustainable methods (e.g., organic farming, crop rotation) ensure long-term productivity and environmental health.

Question 9

If the Indian hare population (Fig.) drops because of a disease, how would it affect the number of other organisms?

Accepted Answer

Predators: The numbers of foxes and eagles would decrease due to reduced prey (hares), leading to food scarcity.
Plants: Grass and plant populations might increase initially without hare grazing, but overgrowth could alter the habitat.
Deer: Since deer aren’t preyed on by foxes or eagles, their role in this particular chain isn’t disturbed directly.
Why: A decline in a key herbivore like the hare disrupts the food web, affecting both higher (predators) and lower (plants) trophic levels.
Class 8 How Nature Works in Harmony Question Answer (Activities)
Activity 12.1: Let us Explore (Page 191)
Caution: Explore the habitat in groups with your teacher.
Identify two habitats in your surroundings.
These could be any two of the following: a pond, a forest, an agricultural farm, or even a large tree like a banyan, mango, or pilkhan (white fig) tree.
List the living beings and non-living things that you observe in these habitats.
Record your observations in the Table.
Answer:
Pond: Noticed fish swimming and water as the main components.
Forest: Observed plants (grass, trees), birds, and soil as key elements.
Recorded Observations in a Table.
Different components of two habitats
Activity 12.2: Let us Record (Page 193)
We can understand the population of a particular type of plant by counting them at a given place and time.
Divide students into four to five groups.
Each group may identify any two organisms, plant(s) or animal(s).
Mark an area of 1 m × 1 m in your school garden.
Identify four organisms in this area, and count their numbers.
Record the number of organisms in the Table.
Compile the data from all groups.
Answer:
Number of particular organisms at a given space and time
Name of Organism
Population (Number of individual organisms)
Plant 1: (e.g., Grass)
20
Plant 2: (e.g., Marigold)
5
Animal 1: (e.g., Ants)
10
Animal 2: (e.g., Ladybug)
3
Activity 12.3: Let us Read (Page 194)
Researchers conducted a study to see how fish in ponds affect seed production in the plants nearby. They observed two ponds with fish and a large number of flowering plants around them; B without fish and fewer flowering plants around it (Fig.). Think of a reason for these observations.