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Topic 4: Biodiversity and natural resources - Edexcel A-Level Biology B overview

An overview of Topic 4 of Edexcel A-Level Biology B (Salters-Nuffield, 9BN0), covering biodiversity and classification, natural selection and adaptation, plant structure and economic use, and conservation, and how the topic is examined.

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  1. The four dot-point areas
  2. How Topic 4 is examined
  3. How to study Topic 4
  4. Work through the dot points
  5. For the official specification

Topic 4 of Edexcel A-Level Biology B (specification 9BN0, the Salters-Nuffield course) is titled Biodiversity and natural resources. It explores the variety of life, how it arises through natural selection, and how plants and biodiversity are used and conserved. This page maps the four dot-point areas and how they are examined.

The four dot-point areas

Biodiversity and classification
Biodiversity at species, genetic and habitat levels, the index of diversity, and the classification and naming of organisms.
Natural selection and adaptation
The process of natural selection, types of adaptation, evolution and speciation, and the evidence for evolution.
Plant structure and economic use
Plant cells and tissues, plant fibres and starch, the transport of water in the xylem, and the sustainable use of plant products.
Conservation
The reasons for conserving biodiversity, in-situ and ex-situ methods, seed banks and zoos, and balancing conservation with human needs.

How Topic 4 is examined

Topic 4 features strongly in Paper 1 (The natural environment and species survival) and is revisited in the synoptic Paper 3. Expect index-of-diversity calculations, explanations of natural selection and speciation, plant structure-to-function reasoning, and balanced conservation arguments. Several core practicals, such as using transects and investigating plant fibre strength, draw on this topic.

How to study Topic 4

  1. Practise the diversity index. Calculate and interpret D, and explain why evenness matters.
  2. Sequence natural selection. Use variation, competition, survival, reproduction and changing allele frequency.
  3. Link plant structure to function. Explain xylem transport and the strength of plant fibres.
  4. Argue both ways on conservation. Weigh economic, ecological and ethical reasons against human needs.

Work through the dot points

Each dot point has a focused answer page with worked exam questions and cross-links: biodiversity and classification; natural selection and adaptation; plant structure and economic use; and conservation.

For the official specification

Pearson publishes the full specification (9BN0), past papers and mark schemes at qualifications.pearson.com. Always revise from the current specification and Edexcel's own past papers.

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