Biodiversity and Conservation — NCERT Solutions

Concept: Biodiversity is studied at three distinct levels.

Answer:
Biodiversity exists at three main levels:

1. Genetic Diversity: Variation in the genetic makeup (genes) within individuals of the same species. It allows species to adapt to changing environments.

2. Species Diversity: The variety of different species present in a given area. It is measured by the number of species (species richness) and their relative abundance.

3. Ecosystem Diversity: The variety of different ecosystems (such as forests, grasslands, wetlands, deserts, and oceans) present in a region, each supporting unique communities of organisms.

Concept: Hotspots are regions of exceptionally high biodiversity that are also under severe threat.

Answer:
Biodiversity 'hotspots' are geographic areas that are exceptionally rich in species diversity — particularly endemic species (species found nowhere else on Earth) — but are simultaneously under serious threat from human activities such as deforestation, habitat destruction, and urbanisation. To qualify as a hotspot, a region must contain at least 1,500 species of vascular plants as endemics and must have lost at least 70% of its original habitat. Examples include the Western Ghats of India, the Amazon Basin, and the Mediterranean Basin. Conservation efforts are especially focused on these regions.

Concept: Animals provide ecological, economic, and cultural benefits to humans.

Answer:
Animals are important to humankind in several ways:

1. Food: Animals provide food in the form of meat, milk, eggs, honey, and fish, which are essential components of human diet.
2. Agriculture: Draught animals like bullocks and horses have been used for ploughing fields and transportation for centuries.
3. Medicines: Many medicines and vaccines are derived from animal products (e.g., insulin from pigs, anti-venom from snakes).
4. Ecological Balance: Animals play crucial roles in pollination, seed dispersal, and maintaining food chains and food webs.
5. Economic Value: Animals contribute to industries like leather, wool, silk, and tourism (wildlife tourism).
6. Scientific Research: Animals are used in laboratory research to develop life-saving drugs and treatments.

Concept: Exotic species are non-native species introduced into a new environment.

Answer:
Exotic species (also called alien or invasive species) are those species that are not native to a particular region but have been introduced — either intentionally or accidentally — from another part of the world. When exotic species are introduced into a new ecosystem, they may lack natural predators and can multiply rapidly, competing with and displacing native species, thereby threatening local biodiversity. For example, the water hyacinth (Eichhornia crassipes), originally from South America, has become an invasive species in many Indian water bodies, choking aquatic ecosystems.

Given/Concept: Biodiversity performs multiple ecological functions that shape and sustain the natural world.

Answer:

Biodiversity plays the following important roles in shaping nature:

1. Maintenance of Ecological Balance:
Every species in an ecosystem occupies a specific niche and contributes to the functioning of that ecosystem. Biodiversity ensures that energy flows and nutrient cycles (carbon cycle, nitrogen cycle, water cycle) operate efficiently.

2. Productivity of Ecosystems:
Biologically diverse ecosystems are more productive. A variety of plant species ensures better soil fertility, greater biomass production, and more stable food webs.

3. Soil Formation and Protection:
Microorganisms and plants contribute to soil formation through decomposition of organic matter. Plant roots prevent soil erosion, and diverse vegetation maintains soil health.

4. Regulation of Climate:
Forests and other biodiverse ecosystems regulate local and global climate by absorbing carbon dioxide, releasing oxygen, and influencing rainfall patterns through transpiration.

5. Water Purification and Regulation:
Wetlands and forests filter pollutants from water and regulate the water cycle, reducing the risk of floods and droughts.

6. Pollination and Seed Dispersal:
Animals, especially insects (bees, butterflies), birds, and bats, pollinate flowering plants and disperse seeds, enabling plant reproduction and forest regeneration.

7. Resilience to Environmental Change:
Highly biodiverse ecosystems are more resilient — they can better withstand and recover from disturbances such as droughts, floods, diseases, and climate change.

In summary, biodiversity is the foundation upon which all natural processes rest, and its loss can lead to the collapse of entire ecosystems.

Given/Concept: Biodiversity loss is caused by multiple human-induced and natural factors; conservation requires both in-situ and ex-situ strategies.

Answer:

Major Factors Responsible for Loss of Biodiversity:

1. Habitat Destruction and Fragmentation:
Deforestation, urbanisation, agricultural expansion, and mining destroy and fragment natural habitats, leaving species without food, shelter, or breeding grounds. This is the single most important cause of biodiversity loss.

2. Overexploitation:
Overhunting, overfishing, and excessive harvesting of plants and animals for food, medicine, trade, and sport have drastically reduced the populations of many species.

3. Introduction of Exotic/Invasive Species:
Non-native species introduced into new ecosystems can outcompete, prey upon, or bring diseases to native species, leading to their decline or extinction.

4. Pollution:
Air, water, and soil pollution from industrial effluents, pesticides, and plastic waste poison ecosystems and harm or kill many species.

5. Climate Change:
Global warming alters temperature and precipitation patterns, causing habitat shifts, coral bleaching, glacial melting, and sea-level rise — all of which threaten species unable to adapt quickly.

6. Population Growth and Consumerism:
Rapidly growing human populations increase demand for land, water, food, and energy, putting immense pressure on natural ecosystems.

Steps Needed to Prevent Biodiversity Loss:

1. In-situ Conservation:
Protecting species in their natural habitats through the establishment of national parks, wildlife sanctuaries, biosphere reserves, and marine protected areas.

2. Ex-situ Conservation:
Conserving species outside their natural habitats in zoos, botanical gardens, seed banks, and gene banks to prevent extinction.

3. Legal Protection:
Enacting and enforcing strict laws against poaching, illegal trade in wildlife (CITES), and habitat destruction.

4. International Cooperation:
Global agreements such as the Convention on Biological Diversity (CBD, 1992, Rio Earth Summit) and the Ramsar Convention on Wetlands must be implemented effectively by all nations.

5. Sustainable Use of Resources:
Promoting sustainable agriculture, forestry, and fishing practices that do not deplete natural resources beyond their capacity to regenerate.

6. Awareness and Education:
Raising public awareness about the importance of biodiversity and involving local communities in conservation efforts.

7. Restoration of Degraded Ecosystems:
Undertaking afforestation, wetland restoration, and coral reef rehabilitation programmes to restore lost habitats.

By combining these strategies at local, national, and global levels, the accelerating loss of biodiversity can be significantly reduced and eventually halted.