Q1. Which of the following is NOT a service provided by biodiversity?
- Soil formation
- Oxygen depletion
- Nutrient cycling
- Climate stability
Correct Option: 2. Oxygen depletion
Explanation: Biodiversity contributes numerous ecosystem services that benefit humans and the planet. These include soil formation, nutrient cycling, pollution breakdown, climate regulation, and water purification. Biodiversity actually helps maintain and replenish oxygen through processes like photosynthesis by plants and algae. Oxygen depletion is typically caused by pollution (e.g., eutrophication) and is harmful, not a service. Hence, it is not a service provided by biodiversity.
Q2. Which of the following refers to in-situ conservation?
- Zoological park
- Seed bank
- Biosphere reserve
- Cryopreservation
Correct Option: 3. Biosphere reserve
Explanation: In-situ conservation is the protection of species in their natural habitats, allowing them to continue living and evolving in their ecosystems. Examples include biosphere reserves, national parks, wildlife sanctuaries, and reserved forests. It helps preserve ecological processes, genetic diversity, and species interactions. Ex-situ methods like seed banks or zoos involve human intervention and remove species from their natural settings.
Q3. Which of the following is a natural cause of biodiversity loss?
- Industrialization
- Deforestation
- Floods
- Poaching
Correct Option: 3. Floods
Explanation: Floods are considered a natural cause of biodiversity loss. Natural factors such as earthquakes, volcanic eruptions, landslides, and climate changes can lead to habitat destruction and extinction of species. In contrast, industrialization, deforestation, and poaching are anthropogenic (human-made) causes of biodiversity loss. While natural causes are sometimes unavoidable, human activities have become the primary drivers of species extinction today.
Q4. What does the term ‘alpha diversity’ refer to?
- Diversity between ecosystems
- Diversity within a single ecosystem
- Global biodiversity
- Species comparison over time
Correct Option: 2. Diversity within a single ecosystem
Explanation: Alpha diversity refers to the number of species (species richness) within a particular area or ecosystem. It is used to assess the biodiversity of a specific community or habitat. For example, a forest with 40 species of trees would have higher alpha diversity than one with only 20. It differs from beta diversity (comparison between ecosystems) and gamma diversity (overall regional diversity).
Q5. According to IUCN, a species is called Critically Endangered (CR) when:
- It has large populations in the wild
- It has no chance of extinction
- It is likely to become extinct in the next 100 years
- It faces an extremely high risk of extinction in the wild
Correct Option: 4. It faces an extremely high risk of extinction in the wild
Explanation: A species is listed as Critically Endangered (CR) by the IUCN when it meets very strict criteria indicating that it is facing an extremely high risk of extinction in the immediate future. This may be due to factors like:
• A population decline of over 80–90% in 10 years,
• Fewer than 50 mature individuals left,
• A very restricted geographic range,
• Or quantitative analysis showing at least 50% probability of extinction in the next 10 years.
These species need urgent conservation measures to survive.