This definitions covers Key Definitions within Biodiversity and Human Impacts for GCSE Biology. Topic 5: Biodiversity and Human Impacts on Ecosystems It is section 9 of 16 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Topic position
Section 9 of 16
Practice
20 questions
Recall
19 flashcards
📖 Key Definitions
Biodiversity: The variety of all different species of organisms on Earth, or within a particular ecosystem — including the range of habitats and genetic variation within species.
Deforestation: The large-scale removal of forest — for timber, farmland, biofuel crops, or other land uses — resulting in habitat destruction and increased atmospheric CO₂.
Peat bog: A wetland ecosystem where dead plant material accumulates in waterlogged, anaerobic conditions over thousands of years; a major long-term carbon store.
Greenhouse effect: The process by which greenhouse gases (CO₂, methane, water vapour) in the atmosphere absorb outgoing infrared radiation from Earth's surface and re-emit it, raising global temperatures.
Eutrophication: The process whereby excess nutrients (from fertiliser or sewage run-off) enter water, causing rapid algae growth that blocks sunlight and depletes oxygen when the algae die and decompose, killing aquatic organisms.
Breeding programme: A conservation programme in which endangered species are bred in captivity (e.g., in zoos) to maintain or increase their population, with the aim of eventual reintroduction to the wild.
Seed bank: A secure facility where seeds from diverse plant species are collected, frozen, and stored as a safeguard against extinction — allowing species to be reintroduced if lost from the wild.
SSSI (Site of Special Scientific Interest): A protected area in the UK designated because of its exceptional wildlife, plants, or geological features; development and damaging activities are controlled by law.
Quick Check: A farmer drains a peat bog to create agricultural land. Give two environmental problems this causes.
1. Loss of a unique habitat — specialist peat bog species lose their home, reducing biodiversity. 2. Release of CO₂ — draining allows aerobic decomposers to break down the accumulated organic material, releasing CO₂ that had been locked up for centuries, contributing to global warming. (Also accept: destruction of a long-term carbon sink / conversion of a carbon sink to a carbon source.)
Keep building this topic
Read this section alongside the surrounding pages in Biodiversity and Human Impacts. That gives you the full topic sequence instead of a single isolated revision point.
Practice Questions for Biodiversity and Human Impacts
What is the best definition of biodiversity?
A. The total number of individual organisms in an ecosystem
B. The variety of all different species of organisms on Earth or within a particular ecosystem
C. The process by which species adapt to their environment over time
D. The number of plants found in a habitat
1 markfoundation
Explain why deforestation leads to a reduction in biodiversity.
3 marksstandard
Quick Recall Flashcards
What is biodiversity?
The variety of all different species of organisms on Earth, or within a particular ecosystem.
Includes the range of different habitats and genetic variation within species.
What is eutrophication and what causes it?
Eutrophication is when excess nutrients (from fertiliser or sewage run-off) enter water.
This causes rapid algae growth, blocking sunlight to underwater plants.
When algae die and decompose, oxygen is used up, killing aquatic organisms.
20 questions on Biodiversity and Human Impacts — practise free
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