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The greenhouse effect is a natural process that occurs all the time and keeps average global
temperatures at around 17 degrees.

The most important greenhouse gas is carbon dioxide.
It is highly abundant and it remains in the atmosphere for much longer than other greenhouse gases.

50-70% of global warming…

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The concentrations of the greenhouse gases may be very small, but they are increasing.
The result of these increases is the enhanced greenhouse effect, which is causing more heat to be
trapped on Earth, leading to an increase in mean global temperature called global warming.

Effects of Global Warming


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Energy enters an ecosystem as sunlight and is lost as heat.
This heat cannot be recycled.
The flow of energy through an ecosystem is therefore in one direction, that is, it is linear.

The flow of nutrients within an ecosystem is not linear, but cyclic.

All nutrient cycles have one…

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Carbon, in the form of CO2 from air and water, is absorbed by plants when they carry out
It becomes carbon compounds in plant tissues.

Carbon is passed on to primary consumers when they eat the plants.
It's passed on to secondary and tertiary consumers when they eat other…

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Plants take up most of the nitrogen
they need in the form of nitrate ions
which are absorbed using active
transport by the root hairs.

Nitrate ions are very soluble and
leach through the soil.
In natural ecosystems, the nitrate
levels are restored through recycling
of nitrogen-containing compounds.
In agricultural…

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All plants need mineral ions, especially nitrogen.

Intensive food production makes large demands on the soil because mineral ions are continually taken
up by the crops being grown on it.
Mineral ions crops have absorbed are being removed.
In natural ecosystems the minerals that have been removed from the soil…

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Effect Impact

Reduced species Because nitrogen-rich soils favour the growth of grasses ,
diversity nettles and other rapidly growing species.
These outcompete many other species, which die as a result
Leaching Which may lead to pollution of watercourses

Eutrophication Caused by leaching of fertiliser into watercourses


Leaching is the…


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