UPSC MainsZOOLOGY-PAPER-II202215 Marks
Q15.

What is biodiversity? Describe the major types of biodiversities found in nature.

How to Approach

This question requires a comprehensive understanding of biodiversity, moving beyond a simple definition. The answer should define biodiversity, then systematically describe its major types – genetic, species, and ecosystem diversity – providing examples for each. A structured approach, utilizing headings and subheadings, will enhance clarity. Mentioning conservation implications and relevant reports (like those from the IPBES) will add value. Focus on providing detailed explanations rather than just listing types.

Model Answer

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Introduction

Biodiversity, short for biological diversity, is the variety of life at all levels of biological organization. It’s not merely the number of species, but encompasses the genetic differences within species, the diversity of species themselves, and the variety of ecosystems they inhabit. The current rate of biodiversity loss is estimated to be 100 to 1,000 times higher than the natural extinction rate, largely due to human activities. Understanding the different facets of biodiversity is crucial for effective conservation strategies and sustainable development. This answer will detail the major types of biodiversity found in nature, outlining their significance and providing illustrative examples.

Genetic Diversity

Genetic diversity refers to the variation in genes within a species. This variation is the raw material for adaptation and evolution. A population with high genetic diversity is better equipped to cope with environmental changes, diseases, and other stressors.

  • Importance: Enables species to adapt to changing environments, increases resilience to diseases.
  • Examples:
    • Different breeds of dogs (e.g., German Shepherd, Labrador) represent genetic diversity within the species Canis lupus familiaris.
    • Variations in rice varieties – some drought-resistant, others flood-tolerant – demonstrate genetic diversity within Oryza sativa.

Species Diversity

Species diversity refers to the variety of species within a given region or ecosystem. It is often measured by species richness (the number of species) and species evenness (the relative abundance of each species). Species diversity is a key indicator of ecosystem health.

  • Importance: Contributes to ecosystem stability, provides a wider range of ecosystem services.
  • Examples:
    • The Amazon rainforest, with its incredibly high number of plant, animal, and microbial species, is a hotspot of species diversity.
    • Coral reefs are known for their exceptional species diversity, supporting a vast array of marine life.

Ecosystem Diversity

Ecosystem diversity refers to the variety of ecosystems within a given region. Ecosystems are communities of living organisms interacting with their physical environment. This level of diversity encompasses differences in habitats, ecological processes, and nutrient cycles.

  • Importance: Provides a wider range of habitats and ecological niches, supports a greater variety of species.
  • Examples:
    • India exhibits high ecosystem diversity, ranging from Himalayan alpine meadows to tropical rainforests, deserts, and mangrove swamps.
    • The United States encompasses diverse ecosystems like temperate forests, grasslands, deserts, and coastal wetlands.

Relationship between the Types of Biodiversity

These three types of biodiversity are interconnected. Genetic diversity within species allows them to adapt to different ecosystems. Species diversity contributes to the functioning and stability of ecosystems. Loss of any one type of biodiversity can have cascading effects on the others.

Type of Biodiversity Focus Example Significance
Genetic Variation within species Different color morphs of peppered moths Adaptation, resilience
Species Variety of species Number of bird species in a forest Ecosystem function, stability
Ecosystem Variety of habitats Presence of forests, grasslands, and wetlands Habitat provision, ecological services

Beyond these three main types, other levels of biodiversity are also recognized, such as functional diversity (the range of ecological functions performed by species) and phylogenetic diversity (the evolutionary relationships among species). The IPBES Global Assessment Report on Biodiversity and Ecosystem Services (2019) highlights the alarming decline in all these aspects of biodiversity globally.

Conclusion

Biodiversity is a multifaceted concept encompassing genetic, species, and ecosystem diversity, all intricately linked and vital for the health of our planet. The current rate of biodiversity loss poses a significant threat to ecosystem services and human well-being. Effective conservation strategies must address all levels of biodiversity, promoting sustainable practices and mitigating the impacts of human activities. Recognizing the intrinsic value of biodiversity and its crucial role in maintaining a stable and resilient biosphere is paramount for future generations.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Ecosystem Services
The benefits that humans derive from ecosystems, including provisioning services (food, water), regulating services (climate regulation, disease control), supporting services (nutrient cycling, pollination), and cultural services (recreation, aesthetic value).
Biodiversity Hotspot
A biogeographic region with significant levels of biodiversity that is threatened with habitat loss.

Key Statistics

Approximately 1 million animal and plant species are now threatened with extinction, many within decades (IPBES Global Assessment Report, 2019).

Source: IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services)

Forests cover approximately 31% of the world’s land area and harbor over 80% of terrestrial biodiversity (FAO, 2020).

Source: Food and Agriculture Organization of the United Nations (FAO)

Examples

The Great Barrier Reef

The Great Barrier Reef in Australia is a prime example of high species and ecosystem diversity, supporting thousands of marine species and providing crucial ecosystem services like coastal protection and tourism revenue. However, it is severely threatened by climate change and coral bleaching.

Frequently Asked Questions

Why is genetic diversity important even within a single species?

Genetic diversity allows a species to adapt to changing environmental conditions, resist diseases, and avoid inbreeding depression, ultimately increasing its chances of survival.

Topics Covered

BiologyEcologyEnvironmentBiodiversity ConservationEcosystemsSpecies Richness