Exam practice

Individuals of a species have slightly different genes: in sexual reproduction, each offspring gets a new mix of genes from its two parents, and genes sometimes change (mutate). Their surroundings (food, light, soil, climate) also affect how they grow. So no two individuals are exactly alike, as the maize plants of one field show.

In ex-situ conservation, the organism lives outside its natural home, so its natural food, climate and surroundings must be recreated and managed every day, which is costly and laborious. Wild animals become stressed in captivity and often don’t breed well, and only a few individuals can be kept, so the species can’t live its natural life or keep its full variety.

A forest fire burns trees, seedlings and seeds, and kills or drives away animals, especially slow ones and the young, eggs and nests. It destroys their food and shelter all at once. Afterwards the bare soil is washed away by rain, so the forest takes many years to recover, and some species may be lost from that place altogether.

Within about 200 km from south to north, Nepal’s land rises from about 59 m to 8,849 m above sea level. So it has every climate from tropical to arctic-like, with many different ecosystems (118 types), plenty of monsoon rain and varied soils. Each climate and ecosystem has its own plants and animals, so this small country holds about 3.2 % of the world’s plant species and 1.1 % of its animal species, on only 0.1 % of the world’s land.

The variety of living things, plants, animals and microorganisms, with their different structures and abilities, in different environments, at every level from genes to species to ecosystems, is called biodiversity.
Examples: the many varieties of rice grown in Nepal (genetic diversity); the tigers, rhinos, deer, birds and trees of Chitwan (species diversity); Nepal’s tropical forests, hill forests, alpine meadows, lakes and rivers (ecosystem diversity).

The two methods are in-situ and ex-situ conservation.
In-situ conservation protects plants and animals in their own natural habitat, in national parks, wildlife reserves, hunting reserves and conservation areas. The organisms live naturally, all the species of the area are protected together, and it is the cheapest way to protect large numbers. Its challenges are poaching, forest fires and diseases. Nepal has 13 national parks (as of 2026), a wildlife reserve, a hunting reserve and 6 conservation areas.
Other measures: controlling poaching and the illegal wildlife trade; making more protected areas; controlling overgrazing, forest fires, pollution and unplanned urbanization; making and enforcing strong laws; and making people aware of the importance of biodiversity.

1. Deforestation: clearing forests for farms, houses and roads, and taking too much firewood and fodder, destroys habitats.
2. Overgrazing: livestock eat and trample seedlings, so forests can’t regrow.
3. Pollution: chemicals from industries, farms and towns poison soil, water and the life in them.
4. Unplanned construction and mining: roads, dams and quarries without planning cause landslides and erosion and cut wildlife habitats apart.
5. Poaching and illegal trade: reduce the numbers of animals such as rhinos, tigers and pangolins.
6. Invasive species: plants such as banmara and water hyacinth, spread by people, push out native plants.
7. Climate change: caused mainly by burning fuels, it changes the homes and seasons that many species depend on.

Nepal covers only 0.1 % of the world’s land but is very rich in biodiversity, because its altitude ranges from about 59 m to 8,849 m, giving climates from tropical to arctic-like, with good rainfall and fertile soils. It is often ranked about 25th–27th in the world and 2nd in South Asia. It has about 3.2 % of the world’s plant species and 1.1 % of its animal species, 118 types of ecosystem and 35 types of forest; for example, about 6,973 kinds of flowering plants, 886 birds and 185 mammals. Some species are found only in Nepal, such as the spiny babbler; rare animals such as the one-horned rhino, the Bengal tiger, the snow leopard and the wild yak live here, along with about 32 species of rhododendron and native crops such as Jumla’s Marsi rice. About a quarter of the country is protected. But habitat loss, overgrazing, invasive plants, poaching and climate change still threaten many species.

1. Overgrazing in forests, which stops new trees growing.
2. Chemical pollution from industries.
3. Careless mining and blasting, causing landslides and erosion.
4. Unplanned construction of roads, buildings, dams and bridges, destroying habitats.
5. Collecting too much fodder and firewood, causing deforestation.
6. Clearing forests for farmland and houses.
7. Forest fires.
8. Floods and landslides.
9. Global warming and climate change.
10. Poaching and illegal trade in wildlife.
11. Invasive plants, such as banmara and water hyacinth, pushing out native plants.
12. Illegal and careless mining of sand, gravel and stones from rivers.

Species richness is the number of different species in a place. It is the most common measure of biodiversity: the more species an area has, the richer its biodiversity. A species-rich ecosystem has many food chains linked into a web, so if one species declines, others can take its place; it is more stable, more productive, and recovers better from droughts, diseases and other changes. Species richness also gives people more resources: food, medicines, timber and tourism.

By kind of organism: floral diversity (plants) and faunal diversity (animals).
By level: genetic diversity (variety within a species), species diversity (variety of species in a place) and ecosystem diversity (variety of ecosystems).

• i.In-situ conservation: a national park protects wildlife in its natural habitat.
• ii.Advantages: the animals and plants live naturally, in their own habitat, with their natural food and climate; every species in the area, endangered or not, is protected together, with their food chains and the whole ecosystem; large populations can be protected cheaply; the animals breed naturally and keep their full genetic variety; and the park brings income from tourism, which is shared with local people in the buffer zone.

How it works: hunting, grazing, tree cutting and settlement are controlled inside the park; the army and park staff patrol against poachers; the animals are counted and studied; and local people are involved through buffer zone user groups. In Chitwan, this has brought the one-horned rhino and the Bengal tiger back from near extinction.

Development depends on natural resources: land, water, forests and a stable climate. If a project ignores the environment, it may cause landslides, floods, pollution and loss of biodiversity, which harm people and can destroy the project itself (a road swept away by landslides, a dam filled with silt). Only development that conserves the environment lasts and benefits future generations.

Sustainable development shares resources and opportunities fairly, ends poverty and discrimination, empowers women and marginalized groups, respects people’s culture and lets them take part in decisions. When everyone gets a fair share and a voice, there is less conflict, and people live together in harmony.

Biodiversity provides the ecosystem services that development depends on: food, water, fertile soil, timber, medicines, pollination, protection from landslides and floods, and income from tourism. When biodiversity is lost, these services decline, ecosystems become unstable, and people, especially the poor who depend directly on nature, suffer. So development can’t last without conserving biodiversity.

Development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs, by balancing economic, social and environmental aspects, is called sustainable development (Brundtland Commission, 1987).
Example: community forestry in Nepal. Local user groups protect the forest, take only as much firewood, fodder and timber as grows back, and use the income for schools and roads. The forest, the community and its income all keep growing. Another example: a road built with drains, gentle slopes and planted grass, so it lasts for many years.

The principles are:

1. the principle of ecosystem and biodiversity conservation;
2. the principle of population control and human resource management;
3. the principle of cultural conservation and public participation.

Cultural conservation and public participation: development lasts only when the people it serves take part in it and their traditions and culture are respected. When villagers plan, build and look after a project, such as an irrigation canal or a community forest, they feel it is theirs and protect it, so it lasts. This principle also stresses conserving cultural heritage, and social justice and peace.

Foundation: skilled, educated people are what development is built with. Engineers design safe roads and bridges, scientists find renewable energy and better crops, doctors and teachers improve health and education, and aware citizens conserve forests and use resources wisely.

Destroyer: the same skills can be used carelessly or greedily: to cut forests faster, build badly planned roads that cause landslides, run polluting factories, poach wildlife with modern weapons, or overuse resources for quick profit.

So it depends on how skills are used. Education must teach not only skills but also responsibility towards the environment and future generations.

Natural resources are limited, the population is growing, and careless development is causing deforestation, pollution, landslides, loss of biodiversity and climate change. Sustainable development is needed to stop this.
Importance: it keeps the environment in balance and controls pollution; it conserves natural resources and teaches people to use them sensibly; it makes big projects safe and long-lasting; it reduces inequality and brings social justice and peace; and it gives everyone a fair economic opportunity, so that future generations inherit a healthy environment as well as development.

The Sustainable Development Goals (SDGs) are 17 goals, with 169 targets, agreed by all 193 members of the United Nations in 2015, for the whole world to achieve between 2016 and 2030: ending poverty and hunger, health, education, clean water, clean energy, decent work, climate action, and life on land and in water, among others.
Nepal’s efforts:

1. Nepal has made its own SDG roadmap and carries it out through its periodic plans and budgets.
2. A Climate Change Council (since 2009) guides programs on water, watersheds and biodiversity; the 2009 cabinet meeting at Kala Patthar drew the world’s attention to climate change; Tsho Rolpa and Imja glacial lakes were lowered to reduce the risk of floods.
3. Community forestry (since the late 1970s, and the Forest Act of 1993) has increased forest cover.
4. The Fourteenth, Fifteenth and Sixteenth Plans have focused on reducing poverty, vocational education, jobs, sanitation, health, pollution control and a clean, green environment.
5. The National Environment Policy, 2076 and the Environment Protection Act, 2076 protect people’s right to a clean environment and make polluters pay.
6. Protected areas cover about a quarter of the country, and tigers and rhinos have increased.

Nepal is working to graduate from the group of Least Developed Countries; it was due to in November 2026 and has asked the UN to put it off to 2029 (as of October 2026).

1. Build drains along the road and across it, so that rainwater doesn’t soak into the slope or run over the road.
2. Cut slopes gently or in steps, protect them with retaining or gabion walls, and plant grass, shrubs and trees (bioengineering) on them.
3. Don’t tip the dug-out soil down the hillside or into rivers; dispose of it safely, and avoid unnecessary blasting and tree cutting. (Also: study the land before building, avoid landslide-prone slopes, and involve local people in planning and maintenance.)

The three aspects (pillars) are the economic, social and environmental aspects.
Draw three overlapping circles, labeled Environmental, Social and Economic, as in Figure 4.7. Where environment and society overlap, development is bearable; where society and economy overlap, it is equitable (fair); where environment and economy overlap, it is viable; and only in the center, where all three overlap, is it sustainable.
They depend on one another: the economy depends on natural resources (environment) and on healthy, educated people (society); society needs income (economy) and a healthy environment; and the environment is conserved only when people are not forced by poverty to overuse it and when the economy doesn’t exploit it. If any one is ignored, development doesn’t last.

1. Protect local forests, wetlands, rivers and grasslands, and support community forests.
2. Run tree-planting and bioengineering programs on bare and landslide-prone slopes.
3. Control overgrazing, forest fires and illegal mining of sand, gravel and stones from rivers.
4. Remove invasive plants such as banmara and water hyacinth, and promote native species.
5. Conserve native crops and seeds (community seed banks) and promote organic farming with less pesticide.
6. Make and enforce local rules against poaching and the illegal wildlife trade.
7. Manage waste and sewage so that they don’t pollute rivers and ponds.
8. Run awareness programs in schools and communities, and involve local people, especially women and indigenous communities, in decisions.