Biodiversity under threat — WJEC A-Level Geography Revision

    This topic explores the measures of biodiversity, the threats to biodiversity from direct and indirect human actions at various scales, and the identificat

    Topic Synopsis

    This topic explores the measures of biodiversity, the threats to biodiversity from direct and indirect human actions at various scales, and the identification of ecosystems at greatest risk, specifically tropical rainforests, coral reefs, and wetlands.

    Key Concepts & Core Principles

    Exam Tips & Revision Strategies

    Common Misconceptions & Mistakes to Avoid

    Examiner Marking Points

    Biodiversity under threat

    WJEC
    A-Level

    This topic explores the measures of biodiversity, the threats to biodiversity from direct and indirect human actions at various scales, and the identification of ecosystems at greatest risk, specifically tropical rainforests, coral reefs, and wetlands.

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    Objectives
    4
    Exam Tips
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    Pitfalls
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    Key Terms
    5
    Mark Points

    Topic Overview

    Biodiversity under threat examines the variety of life on Earth and the accelerating pressures that are causing its decline. This topic covers the concept of biodiversity—including genetic, species, and ecosystem diversity—and explores why it is essential for ecosystem services, human well-being, and planetary health. You will study the main threats: habitat loss, overexploitation, invasive species, pollution, and climate change, with a focus on how these interact and amplify each other.

    The topic is central to understanding contemporary environmental crises and links directly to sustainability, conservation, and global governance. In the WJEC A-Level, you will analyse case studies such as tropical rainforests (e.g., Amazon), coral reefs (e.g., Great Barrier Reef), and UK habitats (e.g., peatlands). You will evaluate conservation strategies like protected areas, international agreements (CBD, CITES), and community-based approaches. Understanding these issues is vital for informed citizenship and for tackling questions on human-environment interactions.

    Biodiversity loss is not just an environmental issue—it has economic, social, and ethical dimensions. The topic connects to other themes in geography, such as climate change, globalisation, and sustainable development. By studying biodiversity under threat, you develop skills in critical thinking, data analysis (e.g., interpreting extinction rates), and evaluating policy effectiveness. This knowledge is assessed through both short-answer and extended essay questions, often requiring you to use specific examples and evaluate competing perspectives.

    Key Concepts

    Core ideas you must understand for this topic

    • →Biodiversity: The variety of life at genetic, species, and ecosystem levels; measured by richness (number of species) and evenness (relative abundance).
    • →Threats: HIPPO (Habitat loss, Invasive species, Pollution, Population, Overexploitation) and climate change as a multiplier.
    • →Conservation strategies: In-situ (e.g., national parks) vs ex-situ (e.g., zoos, seed banks); international agreements like the Convention on Biological Diversity (CBD) and CITES.
    • →Ecosystem services: Provisioning (food, water), regulating (climate, flood control), supporting (nutrient cycling), and cultural (recreation, spiritual).
    • →Tipping points: Thresholds beyond which ecosystems shift irreversibly, e.g., coral bleaching leading to reef collapse.

    What You Need to Demonstrate

    Key skills and knowledge for this topic

    • Definition and measurement of biodiversity
    • Identification of direct threats to biodiversity (e.g., habitat destruction, overexploitation)
    • Identification of indirect threats to biodiversity (e.g., climate change, pollution)
    • Analysis of threats operating at local to global scales
    • Identification of ecosystems at greatest risk: tropical rainforests, coral reefs, and wetlands

    Marking Points

    Key points examiners look for in your answers

    • Definition and measurement of biodiversity
    • Identification of direct threats to biodiversity (e.g., habitat destruction, overexploitation)
    • Identification of indirect threats to biodiversity (e.g., climate change, pollution)
    • Analysis of threats operating at local to global scales
    • Identification of ecosystems at greatest risk: tropical rainforests, coral reefs, and wetlands

    Examiner Tips

    Expert advice for maximising your marks

    • 💡Ensure you can distinguish between direct and indirect human actions affecting biodiversity
    • 💡Use specific examples of ecosystems at risk to support your arguments
    • 💡Consider the spatial scale of threats, from local habitat loss to global climate change impacts
    • 💡Link biodiversity threats to the concept of ecosystem services and human well-being
    • 💡Use specific, named examples (e.g., Amazon rainforest deforestation for soy/beef, Great Barrier Reef bleaching events, UK hedgehog decline) to illustrate points—generic answers lose marks.
    • 💡Evaluate conservation strategies: don't just describe them; discuss their strengths and weaknesses, using criteria like cost, effectiveness, and social acceptability. For instance, compare top-down (government-led) vs bottom-up (community-based) approaches.
    • 💡Link biodiversity loss to other geographical concepts: e.g., how globalisation drives overexploitation (demand for palm oil), or how climate change exacerbates habitat fragmentation. This shows synoptic understanding.

    Common Mistakes

    Pitfalls to avoid in your exam answers

    • Confusing direct and indirect threats to biodiversity
    • Failing to link threats to specific scales (local to global)
    • Generalizing threats without referencing the specific ecosystems at risk (rainforests, coral reefs, wetlands)
    • Lack of precision in defining biodiversity
    • Misconception: Biodiversity only refers to the number of species. Correction: It also includes genetic diversity within species and ecosystem diversity (variety of habitats and communities).
    • Misconception: Climate change is the biggest threat to biodiversity. Correction: Currently, habitat loss (especially from agriculture and urbanisation) is the primary driver, though climate change is accelerating and will become dominant.
    • Misconception: Protected areas always effectively conserve biodiversity. Correction: Many are poorly managed, underfunded, or suffer from 'paper park' syndrome; also, they may not account for climate change impacts on species ranges.

    Frequently Asked Questions

    Common questions students ask about this topic

    Before You Start

    Prior knowledge that will help with this topic

    • •Ecosystems and their functioning (e.g., nutrient cycles, food webs) from GCSE or AS Geography.
    • •Basic understanding of climate change causes and impacts.
    • •Familiarity with map skills and interpreting graphs (e.g., species-area curves, extinction rates).

    Likely Command Words

    How questions on this topic are typically asked

    Explain
    Assess
    Discuss
    Evaluate
    Identify

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