Biodiversity and Conservation — NCERT Solutions

Biodiversity is important for ecosystem functioning because communities with greater species richness are generally more stable, more productive, and more resistant or resilient to disturbances and invasions.

The chapter explains this through the rivet popper hypothesis: if species are lost one by one, the ecosystem may continue to function for some time, but as more species disappear, it becomes weaker and less stable. Loss of important species can seriously affect ecosystem processes. Also, Tilman’s experiments showed that plots with more species had less year-to-year variation in biomass and higher productivity.

Sacred groves are tracts of forest set aside by local communities because they are considered sacred; the trees and wildlife within them are venerated and given total protection.

Their role in conservation is important because they act as refuges for rare and threatened plants and animals. In places like Meghalaya, sacred groves are the last refuges for many rare and threatened plants. They help preserve biodiversity through traditional community protection.

Flood control and soil erosion control are achieved by the biotic components, especially plants/forest vegetation.

• The roots of plants bind the soil and prevent it from being washed away, thus reducing soil erosion.
• Forest cover helps absorb rainfall, slows down surface runoff, and allows water to percolate into the soil, which reduces the risk of floods.

So, by holding soil together and regulating water flow, living organisms in ecosystems provide these services.

Animals achieved greater diversification because:

1. They are a very large and varied group, especially insects, which form the most species-rich taxonomic group.
2. Adaptive radiation over long evolutionary time allowed animals to occupy many habitats and niches.
3. Tropical regions, where biodiversity is highest, provided more evolutionary time, stable environments, and greater productivity, supporting diversification.
4. Many animal groups, particularly insects, have short life cycles, high reproductive rates, and strong ability to adapt, which can speed up speciation.

Thus, animal diversity became much higher than plant diversity, with insects contributing the largest share.

Yes. We may deliberately try to eliminate a species when it is an invasive alien species that threatens native biodiversity and ecosystem balance.

For example, species like Parthenium, Lantana, water hyacinth, or the African catfish Clarias gariepinus are harmful invaders. Their removal is justified because they:

• compete with native species,
• reduce biodiversity,
• damage ecosystems, and
• threaten indigenous plants and animals.

So, in such cases, making a species extinct in a local area may be justified for conservation of native biodiversity.