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Ecology (Abiotic factors: (non-living) factors which can affect a…
Ecology
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Communities
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`an ecosystem is the interaction of a community of living organisms with the non-living parts of their environments
to survive and reproduce, organisms require a supply of materials from their surroundings and from the other living organisms there
Plants in a community or habitat often compete with each other for light and space, and for water and mineral ions from the soil.
Animals often compete with each other for food, mates and territory.
Within a community each species depends on other species for food, shelter, pollination, seed dispersal etc. If one species is removed it can affect the whole community. This is called interdependence. A stable community is one where all the species and environmental factors are in balance so that population sizes remains fairly constant
Maintaining biodiversity
- breeding programmes for endangered species
- protection and regeneration of rare habitats
- reintroduction of field margins and hedgerows in agricultural areas where farmers grow only one type of crops
- reduction of deforestation and carbon dioxide emissions by some governments
- recycling resources rather than dumping waste in landfill
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levels or organisation
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Feeding relationships within a community can be presented by food chains. All food chains begin with a producer which synthesises molecules. This is usually a green plant or alga which makes glucose by photosynthesis
Producers are eaten by primary consumers, which in turn may be eaten by secondary consumers and then tertiary consumers.
Consumers that kill and eat other animals are predators, and the eaten are prey. In a stable community the numbers of predators and prey rise and fall in cycles.
How materials are cycled
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the carbon cycle returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis
The water cycle provides free water for plants and animals on land before draining into the seas. Water is continuously evaporated and precipitated
Waste management
rapid growth in the human population and an increase in the standard of living mean that increasingly more resources are used and more waste is produced. Unless waste and chemical materials are properly handled, more pollution will be caused
pollution can occur:
- in water, from sewage, fertiliser or toxic chemicals
- in air, from smoke and acidic gases
- on land, from landfill and from toxic chemicals
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Land use
humans reduce the amount of land available for other animals and plants by building, quarrying, farming and dumping waste
The destruction of peat bogs, and other areas of peat to produce garden compost, reduces the area of this habitat and thus the biodiversity
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Global warming
levels of carbon dioxide and methane in the atmosphere are increasing, and contribute to 'global warming'
consequences:
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the distribution of many wild animal and plant species may change as temperature increase and the amount of rainfall changes in different areas
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Biodiversity: the variety of all the different species of organisms on earth, or within an ecosystem
a great biodiversity ensures the stability of ecosystems by reducing the dependence of one species in another for food, shelter and the maintenance f the physical environment
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