Question 5.
What are the major causes of species losses in a geographical region?

Answer:
The major causes of species losses are collectively known as the Evil Quartet. These are:

1. Habitat loss and fragmentation:
   Destruction of natural habitats due to deforestation, urbanization, agriculture, and mining leads to the disappearance of many species.
2. Over-exploitation:
   Excessive hunting, fishing, logging, and harvesting of plants and animals causes rapid population decline.
3. Alien species invasions:
   Introduction of non-native species often leads to competition, predation, or diseases that threaten native species.
4. Co-extinctions:
   When one species becomes extinct, species dependent on it (like parasites, pollinators, or symbiotic partners) may also disappear.

Question 6.
How is biodiversity important for ecosystem functioning?

Answer:
Biodiversity plays a crucial role in maintaining the proper functioning of ecosystems in the following ways:

1. Higher Productivity:
   Diverse ecosystems tend to be more productive because different species perform different ecological roles, improving overall resource use.
2. Stability and Resilience:
   Ecosystems with rich biodiversity can better resist environmental disturbances like drought, diseases, and climate change.
3. Ecosystem Services:
   Biodiversity supports essential services such as:

• Pollination by insects and birds
• Natural pest control
• Nutrient cycling
• Soil formation and protection
• Water purification and conservation

4. Climate Regulation:
   Forests and oceans with high biodiversity help regulate global climate and maintain atmospheric gases through processes like photosynthesis.
5. Balanced Food Webs:
   Presence of diverse species maintains ecological balance and supports stable food chains.

Question 7.
What are sacred groves? What is their role in conservation?

Answer:
Sacred groves are patches of forest or natural vegetation that are protected by local communities, usually due to religious beliefs, cultural traditions, or spiritual significance. These areas are strictly protected, and cutting trees, hunting, or any form of exploitation is traditionally forbidden.

Sacred groves are found in Khasi and Jaintia Hills of Meghalaya, Aravalli Hills of Rajasthan, and the Western Ghats of Karnataka and Maharashtra.

Role in Conservation:

1. Biodiversity Hotspots:
   Sacred groves act as natural habitats for several rare, endemic, and threatened plant and animal species.
2. Ecological Stability:
   They preserve climax vegetation, which supports ecosystem balance and natural ecological processes.
3. Water and Soil Conservation:
   Groves protect watersheds, reduce soil erosion, and maintain groundwater levels.
4. Refuge for Species:
   In places like Meghalaya, sacred groves are the last remaining refuge for many threatened plant species.
5. Cultural and Traditional Conservation:
   Community beliefs ensure strict protection, making sacred groves one of the oldest forms of in-situ conservation in India.

Question 8.
Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?

Answer:
Biotic components of an ecosystem, especially plants, play a major role in controlling floods and preventing soil erosion. The roots of trees hold the soil tightly, stopping it from being washed away by rainwater or blown away by wind. In forests, the canopy formed by leaves and branches slows down the fall of raindrops, so the water reaches the ground gently instead of hitting it forcefully.

This prevents soil from getting loosened and reduces surface runoff. Because water drips slowly to the ground, it does not collect or cause flooding. Trees also help regulate the water cycle by absorbing and releasing water, which further reduces the chances of floods and soil erosion.

Question 9.
The species diversity of plants (22 per cent) is much less than that of animals (72 per cent). What could be the explanations to how animals achieved greater diversification?

Answer:
Animals show greater species diversity than plants mainly because plants create a wide variety of habitats, structures, and food resources. This structural and resource richness offered by plants allows many different animal species to evolve, adapt, and occupy various ecological niches. As a result, animals have undergone greater diversification compared to plants.

Question 10.
Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?

Answer:
Yes. We may deliberately want to make a species extinct when it causes serious harm to humans, crops, or ecosystems. For example, disease-causing organisms such as smallpox virus, polio virus, or malaria-carrying mosquitoes can lead to large-scale illness and death. Eliminating such harmful species helps protect human health and prevents the spread of dangerous diseases. Since these organisms do not play any major positive role in maintaining ecosystem balance, their eradication can be justified for the welfare and safety of human populations.