Loss Of Biodiversity

The correct answer is:

Option 3: threatened species

Explanation:

The Red List refers to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, which is a comprehensive inventory of the conservation status of plant and animal species worldwide. The Red List provides detailed information on the levels of threat faced by species, helping to assess and categorize species that are at risk of extinction.

The categories in the IUCN Red List range from Least Concern to Extinct, with species being classified as Critically Endangered, Endangered, Vulnerable, and so on, depending on how close they are to extinction.

Why other options are incorrect:

Option 1: all economically important plants – The Red List does not focus exclusively on economically important plants, although some species on the Red List may be important economically.

Option 2: plants whose products are in international trade – The Red List includes plants and animals at risk, regardless of whether their products are traded.

Option 4: marine vertebrates only – The Red List includes all types of species, not just marine vertebrates.

Thus, the correct focus of the Red List is on threatened species.

Correct Answer: Option 1 – 1992

The historic Convention on Biological Diversity, famously known as 'The Earth Summit', was held in Rio de Janeiro, Brazil, in the year 1992. This landmark global event was officially titled the United Nations Conference on Environment and Development (UNCED) and remains one of the most significant international efforts to address environmental issues at a planetary scale.

The Earth Summit of 1992 brought together representatives from over 170 countries and resulted in the formulation of crucial documents and agreements aimed at sustainable development and environmental protection. Key outcomes of the summit include:

• The Rio Declaration on Environment and Development
• Agenda 21 – a comprehensive action plan for global sustainable development
• The Convention on Biological Diversity (CBD) – focusing on the conservation and sustainable use of biodiversity
• The United Nations Framework Convention on Climate Change (UNFCCC) – laying the foundation for climate change mitigation

The summit emphasized the principle of “common but differentiated responsibilities”, encouraging all nations to collaborate while recognizing their varied capacities and historical roles in environmental degradation.

Conclusion: The Earth Summit of 1992 in Rio de Janeiro marked a pivotal moment in the global movement toward sustainable development and biodiversity conservation. For students preparing for competitive exams like NEET, UPSC, or environmental science Olympiads, remembering this date is crucial for scoring in environmental and ecology-based questions.

In understanding the major causes of biodiversity loss, it's crucial to identify the key factors contributing to this global issue. Here are the explanations for the options:

• Over exploitation: This involves excessive use of natural resources, leading to depletion and harm to ecosystems, making it a major cause of biodiversity loss.
• Co-extinction: This occurs when the extinction of one species leads to the extinction of another, such as a host-specific insect with its host plant.
• Mutation: Genetic mutations are random changes in DNA that can lead to diversity but are not a direct cause of biodiversity loss.
• Habitat loss and fragmentation: Destruction and division of habitats reduce species populations and genetic diversity, directly impacting biodiversity.
• Migration: While migration itself is a natural biological process, when disrupted by human activities, it can indirectly affect biodiversity.

Thus, the major causes of biodiversity loss from the given options are:

• A. Over exploitation
• B. Co-extinction
• D. Habitat loss and fragmentation

Therefore, the correct choice is: A, B and D only.