📌Definition Table

Term	Definition
Biodiversity	The variety of life in all its forms, levels, and combinations, including genetic, species, and ecosystem diversity.
Genetic Diversity	The variation of genes within a species, providing the raw material for adaptation and evolution.
Species Diversity	The number of different species and their relative abundance in an area.
Ecosystem Diversity	The variety of ecosystems and ecological processes within the biosphere.
Endemic Species	Species found only in a specific geographic location.

📌Introduction

Biodiversity is the foundation of ecosystem stability, resilience, and productivity. It is essential for maintaining ecological balance and supporting human well-being through ecosystem services such as food production, water purification, climate regulation, and cultural enrichment. Biodiversity exists at multiple levels — from genetic diversity within species to the variety of ecosystems across landscapes — and is the result of millions of years of evolutionary processes. Its preservation is vital for sustaining life on Earth and adapting to environmental changes.

📌 Levels of Biodiversity

• Genetic diversity ensures populations can adapt to changing environments.
• Species diversity maintains ecosystem balance and resilience.
• Ecosystem diversity supports a wide range of ecological processes.
• All levels are interconnected and influence each other.
• Loss at one level often impacts the others.
• Measurement uses indices such as Shannon-Wiener or Simpson’s index.

🧠 Examiner Tip: When describing biodiversity, always specify the level (genetic, species, or ecosystem) and give an example.

📌 Importance to Ecosystem Functioning

• Enhances ecosystem productivity through niche differentiation.
• Increases stability against environmental fluctuations.
• Supports nutrient cycling and energy flow.
• Provides habitat for a variety of organisms.
• Ensures pollination and seed dispersal.
• Promotes resilience to invasive species and disease outbreaks.

🧬 IA Tips & Guidance: An IA could investigate species diversity in different habitats using a quadrat or transect sampling method.

📌 Importance to Humans

• Provisioning services: food, water, raw materials, medicines.
• Regulating services: climate regulation, flood control, disease regulation.
• Cultural services: recreation, spiritual value, education.
• Supporting services: soil formation, primary production.
• Acts as a genetic resource for crop and livestock improvement.
• Provides economic benefits through tourism and ecosystem products.

🌐 EE Focus: An EE could explore the relationship between biodiversity and crop productivity, analysing how species richness affects yields.

📌 Indicator of Environmental Health

• Healthy ecosystems usually have high biodiversity.
• Sudden biodiversity loss signals environmental degradation.
• Bioindicator species can signal changes in ecosystem quality.
• Monitoring biodiversity helps track climate change impacts.
• Protecting biodiversity protects ecosystem services.
• Restoration ecology aims to recover biodiversity in degraded areas.

❤️ CAS Link: A CAS project could involve organising a biodiversity survey in a local park and presenting results to raise community awareness.

📌 Global Biodiversity Patterns

• Biodiversity is highest in tropical regions and decreases toward the poles.
• Hotspots are regions with high species richness and high threat levels.
• Island ecosystems often have high endemism but are vulnerable to disturbances.
• Mountain regions offer diverse microhabitats increasing species diversity.
• Marine biodiversity is concentrated in coral reefs and coastal zones.
• Climate, geography, and evolutionary history shape biodiversity patterns.

🔍 TOK Perspective: Biodiversity valuation involves subjective decisions about which species and ecosystems are most important, reflecting human perspectives and cultural values.

📝 Paper 2:
Be ready to define biodiversity at different levels, explain its importance to ecosystems and humans, and give examples of biodiversity hotspots.