subjects · AQA · spec 8461
Biology
6 curated decks for AQA 8461, every card linked to the moment it was explained. Preview one below.
sample deck
GCSE Biology: Ecology notes (PDF)
AQA Topic 7 Ecology — ecosystems, food chains, the carbon and water cycles and biodiversity — detailed notes from Physics & Maths Tutor. Each card deep-links to the page.
An {ecosystem} is the interaction of a community with non-living (abiotic) parts of the environment.
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ecosystem
What is a stable community in ecology?
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One where all the biotic and abiotic factors are in balance, so population sizes remain roughly constant.
Why does soil pH affect the rate at which mineral ions return to soil?
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Soil pH affects the rate of decay, and decay returns mineral ions to the soil.
Why can a new pathogen rapidly wipe out a population?
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The population has no resistance to it.
{Extremophiles} are organisms that live in environments with extreme conditions such as high temperature, pressure or salt concentration.
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Extremophiles
What type of organisms are always producers in a food chain?
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Photosynthetic organisms, usually green plants or algae.
What happens to predator populations after prey populations increase?
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The predator population will also increase (because more food is available).
How is CO₂ removed from the air in the carbon cycle?
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Through photosynthesis by green plants and algae.
Why must methane produced in biogas generators be used immediately?
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It cannot be stored as a liquid.
Why does high biodiversity make an ecosystem more stable?
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Species are less dependent on each other for things such as food and shelter.
Interdependence describes how organisms in a community depend on {other organisms} for vital services.
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other organisms
What is deforestation?
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The cutting down of a large number of trees in the same area, in order to use the land for something else.
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