Students rely on Class 8 Science Extra Questions and Class 8 Curiosity Chapter 12 Extra Question Answer How Nature Works in Harmony to help self-study at home.
Class 8 Science Chapter 12 How Nature Works in Harmony Extra Questions
Class 8 Science Chapter 12 Extra Questions on How Nature Works in Harmony
How Nature Works in Harmony Class 8 Very Short Question Answer
Question 1.
Can you call a city park as a habitat?
Answer:
Yes, Because it provides food, shelter, and space for organisms like birds, insests, and plants.
Question 2.
Why might a tree trunk or bark be a suitable habitat for certain organisms? (Competency Based Que.)
Answer:
It offers shelter, moisture, food (like sap or insects), and a stable surface for mosses, fungi, insects, and small reptiles.
Question 3.
What are the abiotic components? Give one examples.
Answer:
Abiotic components are the non-living physical and chemical components in an ecosystem, e.g., sunlight.
Question 4.
Why does temperature limit the kind of organisms in polar regions?
Answer:
Animals which are adapted to cold climate can survive low temperatures and harsh conditions.
Question 5.
What are biotic components? Give two examples.
Answer:
Biotic components of a habitat includes all the living things, e.g. plant and cow.
Question 6.
Name three biotic and three abiotic components found is a pond.
Answer:
Biotic components : fish, frog, turtles.
Abiotic components : oxygen, water, sunlight.
Question 7.
What is meant by a balanced habitat?
Answer:
A balanced habitat is an ecosystem where all living (biotic) and non-living (abiotic) components interact in harmony, maintaining a stable environment.
Question 8.
Which abiotic factor influences the activity pattern of both the rodent and the snake?
Answer:
The abiotic factor that influence the activity pattern of both the rodent and snake is temperature.
Question 9.
Define population with example.
Answer:
A population refers to a group of individuals of the same species living in a particular area at the same time. Example A school of fish in a pond.
Question 10.
Can a community exist without any one group i.e., plants, animals or microbes? (Competency Based Que.)
Answer:
No, a community cannot exist without any one group i.e., plants, animals, and microbes because all three are interdependent. Without any one group, the balance of the ecosystem would break down.
Question 11.
What is the relationships between population and communities?
Answer:
A population is a group of individuals of same species, while a community includes all the different populations interacting in the same environment.
Question 12.
What is meant by population interaction in an ecosystem?
Answer:
Population interaction refers to the ways in which
different populations living in the same habitat interact with each other for food, shelter, reproduction or survival.
Question 13.
Name the type of interaction when both species benefits from the relationship.
Answer:
Mutualism
Question 14.
Consider the following figure and identify the types of interaction between them. (Competency Based Que.)
im1
Answer:
It represents mutalism, as both partners get benefited.
Question 15.
Classify these as natural and man – made ecosystems: lake, aquarium, mangrove, crop field.
Answer:
Natural ecosystem Lake, mangrove
Artificial ecosystem Aquarium, and crop field
Question 16.
What is an aquatic ecosystem?
Answer:
An aquatic ecosystem is a water based environment like ponds, lakes, rivers, oceans and wetlands where organisms interact with each other and with their water environment.
Question 17.
Arrange the following according to the ecosystem hierarchy from smallest to largest.
Community, individual, ecosystem population
Answer:
Individual → population → community → ecosystem
Question 18.
Why can’t consumers make their own food like producers?
Answer:
Consumers cannot make their own food because they lack chlorophyll and the ability to perform photosynthesis.
Question 19.
Classify the following organisms into carnivores and omnivores.
Crows, leopard, tiger, humans, mice, hawk, foxes
Answer:
Carnivores : Leopard, tiger hawk
Omnivores : Crows, humans, mice
Question 20.
Can an organism be part of more than one trophic level? Give an example.
Answer:
Yes, A bear is a herbivore when eating beeries and a carnivores when eating fish.
Question 21.
Why are large carnivores essential for maintaing ecosystem balance?
Answer:
Large carnivores control prey populations, prevent overgrazing and maintain healthy ecosystem.
Question 22.
In an aquatic food chain.
Phytoplankton → Zooplankton Small fish Big fish → Shark
Identify Herbivores, Small carnivores and Large carnivores.
Answer:
Herbivores : Zooplankton
Small carnivores : Small fish Large carnivores Shark
Question 23.
Why is decomposition considered a critical process for the survival of producers? (Competency Based Que.)
Answer:
Decomposition is essential because it recycles nutrients like nitrogen, phosphorus and carbon back into the soil. These nutrients are absorbed by producers to grow and carry out photosynthesis.
Question 24.
Why does the death of aquatic plants lead to a drop in fish population in polluted water bodies?
Answer:
Aquatic plants provide oxygen, food as well as shelter to fish. When these plants die due to pollution, oxygen levels decrease and fish loose both habitat and food, leading to a decline in the population.
Question 25.
Sunderbans is the largest mangrove forest in the world. Write the location of Sunderbans.
Answer:
Sunderbans are located at the meeting point of the
Ganga and Brahmaputra rivers. It spreads across India and Bangladesh.
Question 26.
Protected areas are special regions set aside by the government to qonserve wildlife, forests, and natural habits. Write any two protected areas.
Answer:
Nilgiri Biosphere Reserve (Western Ghats) and Chilika lake (Odisha)
Question 27.
What would happen if farmers only used synthetic fertilisers year after year without using compost or organic methods?
Answer:
If farmers use only synthetic fertilisers every year, soil fertility reduces, beneficial microbes die and the soil becomes hard and less productive.
How Nature Works in Harmony Class 8 Short Question Answer
Question 1.
If climate change made nights warmer than usual, how might this affect the snake’s behavior or Survival? (Competency Based Que.)
Answer:
Snakes might become more active or shift their routine if nights become warmer. However, if nights become too warm, it could disturb their natural rhythm, affecting feeding or matingt Long – term changes may lead to population decline or migration to cooler areas.
Question 2.
How does mutualism differ from other interactions like parasitism or competition?
Answer:
Mutualism : Both species benefit. Example Bees get nectar; flowers get pollinated.
Parasitism : One benefits, the other is harmed.
Example : Ticks feed on dog body.
Competition : Both species struggle for the same resource and may be harmed.
Example : Two plants competing for sunlight.
Question 3.
In commensalism, if the unaffected organism disappears, what might happen to the one that benefits?
Answer:
The benefiting organism might lose access to food, shelter, or movement support. Though the unaffected organism didn’t gain anything, its presence was essential. Without it, the other may struggle to survive or need to adapt to a new partner or strategy.
Question 4.
You see birds sitting on cows without harming them. What kind of interaction is this? How is it useful? (Competency Based Que.)
Answer:
The interaction is called commensalism. In this relationship, the bird benefits by eating insects and parasites from the cow’s body, while the cow is not harmed or helped.
It is useful because it helps the bird get food easily and sometimes even reduces irritation for the cow, although the cow does not depend on it.
Question 5.
An ecosystem is a system where biotic component interact with each other and with the abiotic component in their environment. What are the three types of ecosystem.
Answer:
There are three main types of ecosystems based on the environment
Terrestrial Ecosystem Found on land (e.g., forest, desert, grassland).
Aquatic Ecosystem : Found in water bodies (e.g., pond, river, ocean).
Artificial Ecosystem : Created and maintained by humans (e.g., crop fields, gardens, aquariums).
Question 6.
Urban gardens are becoming a popular trend in cities. How do such human-made ecosystems benefit the environment and people living in urban areas?
Answer:
Urban gardens help reduce pollution by improving air quality and lowering temperatures through green cover.
They also provide fresh vegetables and fruits, promote mental well-being, and offer a space for biodiversity like butterflies and bees. This supports both the environment and the health of urban populations.
Question 7.
What lessons can we learn from nature to design sustainable human-made ecosystems?
Answer:
From nature, we learn that all organisms live in balance, use resources efficiently, and recycle waste. To design sustainable human-made ecosystems, we should:
Use natural resources wisely (like saving water and energy).
Reduce waste and recycle materials like in nature’s nutrient cycle.
Promote biodiversity by growing different crops and protecting helpful organisms.
Question 8.
Consumers cannot make their own food they depend on producer or other animals for energy, what are the different types of consumers? Explain with examples
Answer:
Consumers cannot make their own food. They depend on plants or other animals for energy.
Types of consumer with examples are
- Primary consumers e.g. Cow, deer and grasshoper
- Secondary consumer e.g. Frog and lizard
- Tertiory consumer e.g. Eagle and lion
Question 9.
A sudden decrease in frog population is observed in a wetland. What could be the practical consequences in the food chain?
Answer:
Frogs eat insects like grasshoppers, so their decline may lead to rise in pests, increasing crop diseases. Frogs are also a food source for snakes and birds so, their predators may suffer from food shortage. The whole food chain gets disturbed, showing frogs play a key role in ecosystem balance.
Question 10.
In a food web, why can some organisms occupy more than one trophic level?
Answer:
Organisms like omnivores can feed at multiple trophic levels. For example, a bear can eat plants (producers) and fish (consumers). This flexibility allows them to play multiple roles in the food web and adapt better to changes in food availability.
Question 11.
Migratory bird, demoiselle crane, visit the water body of khichan village in Jodhpur district during the winter month. These birds are important in many ways .list any three of them.
Answer:
Three importance of demoiselle cranes are
- Maintain prey populaiton in control
- Help in seed dispersal
- Promote tourism, people come to see these beautiful birds.
Question 12.
How does composting represent an application of decomposition?
Answer:
Composting is a controlled biological process where organic waste materials like vegetable peels, leaves, and manure are decomposed by microbes under aerobic conditions. It results in the formation of compost, a nutrient-rich material that improves soil structure and fertility.
Question 13.
How can the removal of too many bullfrogs affect agriculture in surrounding areas?
Answer:
Bullfrogs help control insect and pest populations by feeding on them. Overexploitation reduces their numbers, leading to increase in crop-damaging insects like grasshoppers and flies. This may result in lower, crop yield, higher dependence on chemical pesticides, and increased farming costs, affecting both farmers and the ecosystem.
Question 14.
In what ways do local livelihood activities impact the Sundarbans ecosystem?
Answer:
Activities like cutting mangroves for fuel, overfishing, and honey collection without sustainable methods harm the forest and disturb wildlife habitats.
Over time, this reduces resources, increases human-animal conflicts, and weakens the ecosystem’s ability to recover from natural disasters.
Question 15.
What are protected areas? Explain with examples.
Question 16.
Ravi is a farmer who had used chemical fertilisers on his wheat field for 10 years. At first, he got great harvests. But slowly, the yield reduced. The soil became hard, and earthworms disappeared. Ravi is worried. What mistakes did he make in his farming practices? what should he do now to fix them? (Competency Based Que.)
Answer:
Ravi overused chemical fertilisers, which reduced soil fertility, killed helpful organisms like earthworms, and made the soil hard.
He should now use organic compost, rotate crops, and adopt sustainable farming methods to restore soil health.
Question 17.
Rina noticed that her farm was no longer giving the same amount of vegetables as before. She had been watering her field heavily and ploughing it every week. One day, she dug into the soil and saw very few earthworms and no snails. Her grandfather said the soil had lost its balance.
What could be the reason behind Rina’s low harvest and missing soil animals? (Comptency Based Que.)
Answer:
Rina’s heavy irrigation and repeated ploughing disturbed soil organisms like earthworms and snails. These organisms help keep the soil healthy. Without them, the soil becomes compact and less fertile, leading to poor harvests.
Question 18.
How can natural farming methods reduce dependence on synthetic fertilisers and pesticides?
Answer:
Natural methods like composting, crop rotation, and using bio-pesticides improve soil health and prevent pest outbreaks naturally. This reduces the need for artificial chemicals that can harm the environment and human health.
How Nature Works in Harmony Class 8 Long Question Answer
Question 1.
Explain how biotic and abiotic components interact in a habitat. Give suitable examples to support your answer.
Question 2.
Different population in a community interact in various ways. Justify this statement with a suitable example.
Question 3.
Give reason for the following
(i) Without decomposition, the ecosystem would be filled with dead matter.
(ii) Disruption at one level in a food chain affects the entire chain.
(iii) Green plants are always the first step in a food chain.
(iv) Gardeners grow marigolds near vegetables.
(v) Snakes and owls may appear in the same food web.
Answer:
(i) Dead plants and animals would pile up, and nutrients would not be recycled back into the soil.
(ii) Each organism depends on the previous one for food; if one is removed, others either starve or overpopulate.
(iii) Green plants are producers that make their own food, using sunlight and provide energy to all other organisms in the chain.
(iv) Marigolds naturally repel harmful insects, reducing pest competition and protecting vegetable plants
(v) Snakes and owls are both may feed on similar prey like mice, but at different times, showing overlapping roles in the web.
Question 4.
Explain the impact of human activities on mangrove forest.
How Nature Works in Harmony Class 8 Case Based Questions
Question 1.
Lake Neelima in Uttar Pradesh was once home to a wide variety of fish species. Fishermen from nearby villages relied on the lake for their livelihood. However, over the years, nearby factories began dumping waste into the lake. Additionally, chemical fertilisers and pesticides from surrounding farms were being washed into the lake during rains. Slowly, the fish population started declining. Dead fish were seen floating on the surface, and the water turned green and smelly. Algae grew rapidly, but other aquatic life began disappearing. (comptency Based Que.)
(i) What are the likely causes of fish death in Lake Neelima?
(ii) How did water pollution affect the food chain in the lake?
Answer:
(i) Pollution from factory waste and agricultural runoff led to harmful chemicals and excess nutrients in the water. This caused oxygen depletion and harmful algal blooms, both of which can kill fish.
(ii) With the decline in fish populations, birds and other animals that feed on fish also suffered. Excessive algae blocked sunlight, affecting plants and smaller aquatic organisms, disrupting the entire food chain.
Skill Based Questions
Question 1.
In a grassland ecosystem, grasses are the primary producers. They are eaten by grasshoppers, which are in turn eaten by frogs. The frogs are eaten by snakes, and the snakes are prey to eagles. One year, a pesticide was heavily used by nearby farms. Soon, the grasshopper population dropped sharply. After a few months, frogs were rarely seen, and snake sightings also declined. (Analytical Skill)
What would happen to the eagle population if this disruption continued? Explain.
Question 2.
A large neem tree in a village started losing leaves and drying up. On closer inspection, it was found that many parasite creepers (like dodder) had wrapped themselves around the tree. These plants had no leaves of their own but drew nutrients directly from the neem tree. (Analytical Skill)
Why is this interaction harmful to the ecosystem in the long run?
Question 3.
“Human survival depends on coexisting with nature.” Based on the elephant conflict case, discuss this statement. (Thinking skill)
Question 4.
“A healthy community depends on the diversity and interaction of its members.” Justify this statement using the pond as an example. (Thinking skill)
How Nature Works in Harmony Extra Questions for Practice
Very Short Answer Type Questions
Question 1.
Define habitat.
Question 2.
Give one example of mutualism in nature.
Question 3.
What is a decomposer?
Short Answer Type Questions
Question 1.
How does the interaction between biotic and abiotic components help an ecosystem stay balanced?
Question 2.
What is the difference between a population and a community?
Question 3.
Explain how overuse of chemical fertilisers can harm the soil.
Long Answer Type Question
Question 1.
How does a food chain work in an ecosystem? Explain with an example. Mention different trophic levels involved.