Science - Chapter 12: How Nature Works in Harmony

This is a set about the twelfth chapter of 'Curiosity', eighth-grade textbook by NCERT. It deals with the processes of nature, and ecosystems.

What term describes the place where an organism lives, providing essential conditions for survival?

Habitat

What are the living organisms in a habitat, such as plants and animals, collectively called?

Biotic components

What are the non-living things in a habitat, such as water, soil, and sunlight, collectively called?

Abiotic components

What is a group of the same type of organisms living together in a habitat called?

A population.

What do different populations sharing the same habitat form?

A community.

The interaction between the biotic community and the abiotic components in an area forms an _.

ecosystem

Why might elephants wander into human farms and villages in states like Odisha and West Bengal?

Due to scarcity of vegetation and drying of waterholes in their natural habitat.

What is the purpose of an 'elephant corridor'?

To allow safe movement of elephants between large forest areas without conflicting with human settlements.

Forests, farms, and large trees are examples of what main type of ecosystem?

Terrestrial ecosystems.

Ponds, rivers, and lakes are examples of what main type of ecosystem?

Aquatic ecosystems.

Organisms that make their own food by photosynthesis are called _ or autotrophs.

producers

Organisms that depend on other organisms for their food are called _ or heterotrophs.

consumers

What is the term for consumers that eat only plants?

Herbivores.

What is the term for consumers that eat only other animals?

Carnivores.

What is the term for consumers that eat both plants and animals?

Omnivores.

A simple sequence showing 'who eats whom' in an ecosystem is called a _.

food chain

What is the specific position an organism occupies in a food chain called?

A trophic level.

Which group of organisms is always at the first trophic level in a food chain?

Producers, such as green plants.

What is formed when multiple food chains in an ecosystem are interlinked with each other?

A food web.

Microorganisms like fungi and bacteria that break down dead plants and animals are known as _ or saprotrophs.

decomposers

What is the process of breaking down complex substances in dead organisms into simpler ones called?

Decomposition.

In a study of two ponds, why were there fewer dragonflies in the pond that contained fish?

Because fish eat dragonfly larvae, reducing the dragonfly population.

How did the presence of fish in a pond indirectly lead to more seed production in nearby plants?

Fewer dragonflies (due to fish) meant more pollinators like bees survived, leading to better pollination and seed production.

The large-scale harvesting of which animal in the 1980s led to a rise in agricultural pests in India?

The Indian bullfrog.

What is the ecological term for an interaction where both organisms benefit, such as a bee and a flower?

Mutualism.

What is the ecological term for an interaction where one organism benefits and the other is unaffected, such as an orchid on a tree?

Commensalism.

What is the ecological term for an interaction where one organism benefits and the other is harmed, such as a tick on a dog?

Parasitism.

What is the name of the world's largest mangrove forest, located where the Ganges and Brahmaputra rivers meet?

The Sundarbans.

Why are the Sundarbans ecologically important for coastal protection?

They slow down strong winds and waves during storms and floods.

What are the main human activities threatening the Sundarbans ecosystem?

Cutting mangroves for fuelwood, illegal hunting, overuse of resources, and pollution.

What are parts of land or water set aside to conserve wildlife and their habitats called?

Protected areas.

Fish ponds, farms, and parks are examples of what type of ecosystem?

Human-made ecosystems.

The period in the mid-20th century that saw increased food production due to tractors, synthetic fertilisers, and pesticides is known as the _____.

Green Revolution

What is a major negative consequence of overusing synthetic fertilisers on soil health?

It can reduce soil fertility by decreasing friendly microorganisms and organic matter (humus).

What is the term for growing the same crop repeatedly on the same piece of land?

Monoculture.

How do decomposers like fungi and bacteria play an essential role in an ecosystem?

They recycle important nutrients from dead matter back into the soil, which plants can then use.

In a food chain (Grass → Grasshopper → Frog → Snake), what would happen to the grasshopper population if frogs disappeared?

The grasshopper population would likely increase due to the removal of their predator.

In a food chain (Grass → Grasshopper → Frog → Snake), what would happen to the snake population if frogs disappeared?

The snake population would likely decrease as their food source (frogs) has been removed.

What is the process where wind, water, or insects carry pollen from stamens to carpels of flowers?

Pollination.

Herbivores, such as deer, occupy which trophic level in a food chain?

The second trophic level.

Small carnivores, like frogs, typically occupy which trophic level in a food chain?

The third trophic level.

Why do many birds migrate thousands of miles to India?

To avoid harsh climates in their native habitats and in search of food.

How can migratory birds help farmers?

They act as predators of insect pests, helping to control pest populations and support healthy crop growth.

What happens to an ecosystem when interactions among organisms and their environment keep populations and resources stable?

The ecosystem stays in balance.

How does competition among organisms help maintain balance in an ecosystem?

It helps control population sizes, preventing any one species from multiplying too much and causing an imbalance.

Who was A.J.T. Johnsingh, mentioned in the text?

A famous Indian wildlife biologist who studied forest ecosystems and predator-prey relationships.

According to A.J.T. Johnsingh's research, what is key to predator survival?

A healthy prey population.

What is a negative environmental effect of growing only one type of crop (monoculture)?

It can reduce crop diversity and negatively affect pollinators crucial for food production.

What ancient Indian text, mentioned in the source, emphasises soil health and nourishment through organic manure?

Vrikshayurveda.

What is 'Kunapa Jala' as described in the Vrikshayurveda?

A liquid fertiliser made from fermented animal and plant waste.

If pollution causes plants in a pond to die, what is the immediate effect on the water's oxygen level?

Less oxygen will be produced in the water.

How can a decrease in fish population in a pond lead to problems for nearby farmers?

A reduction in fish can lead to an increase in insects, which may then spread to and damage nearby crops.

What are some examples of protected areas in India mentioned in the text?

Jim Corbett National Park, Manas National Park, and Nilgiri Biosphere Reserve.

The living beings you record in a habitat are termed _____ components.

biotic

The non-living things you observe in a habitat are termed _____ components.

abiotic

Which two abiotic factors affect vegetation and can lead to the shrinking of forests?

Changes in rainfall and temperature.

What are some food items that might attract elephants from forests to nearby farms?

Bananas and sugarcane.

In the forest ecosystem diagram, the deer and rabbit are examples of what type of consumer?

Herbivores.

How do plants contribute to the abiotic environment?

They release oxygen, hold soil to prevent erosion, retain soil moisture, and help cool the atmosphere.

According to the food web diagram, which two animals prey on mice?

The fox and the owl.

According to the food web diagram, what does a hawk eat?

It eats snakes and birds.

Why can an ecosystem not exist with only producers?

Without consumers and decomposers, energy would not be transferred and nutrients from dead producers would not be recycled.

The relationship between an orchid growing on a tree branch is an example of _____.

commensalism

The relationship between a honeybee gathering nectar from a flower is an example of _____.

mutualism

The relationship between a tick feeding on a dog's blood is an example of _____.

parasitism

Why is the balance in an ecosystem described as 'dynamic' rather than 'fixed'?

Because it is constantly adjusting to natural or human-made changes rather than remaining static.

What is the primary role of decomposers in the nutrient cycle?

To return important nutrients from dead organic matter back into the environment.

If the Indian hare population drops due to disease, how might it affect the fox population?

The fox population might decrease due to the loss of a food source.

What is a key difference between natural and human-made ecosystems?

Human-made ecosystems require continuous human care and management to be sustained.

What farming methods are being explored to make agriculture more sustainable?

Organic and natural farming methods.

How can the overuse of pesticides lead to an increase in pest populations in the long term?

It reduces the population of natural predators that control pests, and pests can develop resistance.