Exam practice

biodiversity

balanced environment

reduction

renewable. (The words environment, recycle and non-renewable are not used.)

• It gives us food (grains, fruit, vegetables, fish, meat, milk), medicines (many medicines come from plants such as timur, chiraito and yarsagumba), firewood, timber, fibers and fodder.
• Each living thing is a link in a food chain; with many kinds of living things, the balance of nature is kept: plants make food and oxygen, animals eat them, decomposers return the nutrients to the soil.
• Forests and grasslands protect the soil, store water and keep the air clean and the climate mild.
• Insects such as bees pollinate crops and fruit trees.
• Wild relatives of crops (wild rice, wild fruit) help scientists breed new crops that resist disease and drought.
• National parks, birds and wildlife bring tourists, which gives people jobs and income.
• Many plants and animals are part of our culture and religion (tulsi, pipal, the cow, the national bird danphe).

An ecosystem stays balanced when the amounts of its living things and non-living things stay steady. We can help by:

• not cutting forests faster than they grow back, and planting trees;
• protecting wild animals and their habitats; not hunting or poaching;
• not polluting air, water and soil; managing waste with the 3Rs;
• using natural resources wisely, and only as much as we need;
• conserving wetlands, water sources and soil;
• using organic manure and biological pest control instead of too many chemicals;
• preventing forest fires.

A wetland is land that is soaked with water, or covered by shallow water, for all or much of the year, with marshy ground around it, such as a marsh, a swamp or the shallow edge of a lake. Koshi Tappu, Ghodaghodi and Bishazari are wetlands of Nepal.

• They store rainwater, giving water for drinking, irrigation, fishing and electricity all year.
• They are the habitat of fish and many other plants and animals, and a stopping place for migratory birds.
• They give food: fish, snails, lotus and water chestnut.
• They refill the groundwater, so springs and wells don’t dry up.
• They hold back flood water and keep the local temperature even.
• Lakes such as Rara and Gosaikunda attract tourists and pilgrims.

The main method is the 3R model:

• Reduce: use less and make less waste (cloth bags, no unnecessary packaging).
• Reuse: use things again (jars for storage, bottles as pots, old clothes given away).
• Recycle: make new things from old ones (paper from waste paper, new pots from melted metal, new articles from melted plastic).

Besides these, biodegradable waste can be made into compost or biogas, and what is left can be buried safely in a sanitary landfill. Separating waste at home into biodegradable and non-biodegradable makes all these methods easier.

• Too much chemical fertilizer makes the soil hard and acidic and kills earthworms and the useful bacteria in it, so in time the soil loses its fertility.
• Rain washes the extra fertilizer and insecticide into rivers, ponds and wells, polluting the water and killing fish and other water life.
• Insecticides kill not only pests but also useful insects such as bees (which pollinate crops), and the birds and frogs that eat the poisoned insects, reducing biodiversity.
• The poisons can stay on vegetables and fruit and harm the people who eat them.

• The plants and animals of wetlands (fish, snails, lotus, water chestnut) are food for people and animals.
• Wetlands are the habitat of many plants and animals; fish, frogs and other water animals breed in them.
• Migratory birds come to them in the cold or hot season, to rest, feed and breed.
• They store rainwater and give water for many uses, and refill the groundwater.
• They soak up flood water like a sponge, protecting life and property downstream.
• They keep the local temperature even and help the water cycle.
• They trap mud and dirt and clean the water flowing through them.

• Nepal rises from about 60 m in the Terai to 8,849 m at Sagarmatha within about 200 km, so it has every kind of climate, from tropical to cold and frozen, close together.
• Each climate zone has its own plants and animals: sal forests, rhinos and tigers in the Terai; oak and rhododendron forests and red pandas in the hills; yaks, blue sheep and snow leopards in the Himalaya.
• With good rainfall and many kinds of soil, rivers, lakes and wetlands, there are habitats for many more kinds of living things.
• So although Nepal covers only about 0.1 % of the world’s land, it has more than 6,000 kinds of flowering plants and nearly 900 kinds of birds (about one in twelve of the world’s bird species), and some living things (such as the spiny babbler) are found nowhere else.

(i)

(ii)

(iii)

The environment decides which living things can live in a place: its temperature, rainfall, soil and height suit some plants and animals and not others. So different environments have different living things, and a country with many environments, like Nepal, has great biodiversity.
In turn, living things shape their environment: forests keep the air moist (which helps bring rain), shade the ground and hold the soil; earthworms and decomposers make soil fertile; plants give out oxygen. When biodiversity is lost (forests cut, animals killed), the environment is damaged too: landslides, dry springs, polluted air. When the environment is damaged (pollution, fires), biodiversity is lost. Each depends on the other.

• Use them only as much as needed; don’t waste them (close taps, switch off lights).
• Use renewable resources no faster than nature replaces them: plant a tree for each one cut.
• Use non-renewable resources such as petroleum and metals carefully, and reuse and recycle them.
• Don’t pollute air, water and soil while using them.
• Prefer renewable energy: hydropower, solar, biogas.
• Protect forests from fire, and wildlife from hunting.
• Think of future generations: they need the same resources.

Everything found in nature that is useful to living things is a natural resource, e.g. water, air, soil, forests, minerals, coal and petroleum.
They are classified:

• by their origin: living (biotic) resources such as forests and animals, and non-living (abiotic) resources such as air, water, soil and minerals;
• by whether they can be replaced: renewable resources such as air, water, soil and forests, and non-renewable resources such as coal, petroleum, metals and rocks.

1. Overpopulation: more people need more food, water, land, fuel and houses, so forests are cleared and resources overused.
2. Unmanaged agriculture: too much chemical fertilizer and pesticide ruins the soil and pollutes the water; farming steep slopes without terraces washes soil away.
3. Deforestation and forest fires: forests are lost faster than they grow back, with their wildlife, soil and springs.
4. Pollution: wastes from homes, vehicles and industries make air, water and soil unfit to use.
5. Natural disasters: floods, landslides, droughts and earthquakes destroy forests, farmland and water sources.

Others: overconsumption, unplanned industrial and technical development, unbalanced migration.

Without trees to hold it, the fertile top soil is washed away by rain onto the fields below or into the rivers, so the fields get less fertile. Landslides and floods damage farmland. Springs that water the fields dry up. Farmers also lose fodder, leaf litter for compost, and the birds and insects that eat crop pests and pollinate crops.

Rain runs off the bare ground quickly instead of soaking in, so groundwater is not refilled and springs and wells dry up in the dry season, while floods get worse in the monsoon. The water carries mud into rivers, ponds and lakes, making them muddy and filling them up with silt.

The animals and birds lose their habitat: their homes, shelter, nesting places and food. Many die or have to move away; some come into villages and fields looking for food. Fewer kinds survive, so biodiversity falls.

Forest (trees and timber), soil, and the air and sunlight around them; the forest is also the home of wildlife.

Plant trees and look after the saplings; join or support a community forest group; use wood and paper wisely and recycle paper; use alternatives to firewood (biogas, improved stoves, electricity); help protect forests from fire; and tell others why forests matter.