Māris kļaviņŠ, azamat azizov, JĀnis zaļoksnis environment, pollution, development: the case of uzbekistan

Figure 4.5. 
An 
ecosystem is made up 
of a whole of elements 
of non-living nature 
(biotope) and a whole 
of living organisms 
(species community)

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4. HUMANS AND THE ENVIRONMENT
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Mega-ecosystem
Biosphere
Macro-ecosystem
Biome
Meso-ecosystem
Forest
Micro-ecosystem
Rotting stump
Biosphere as the most comprehensive ecosystem is at the top of 
the hierarchy. Larger territories with homogeneous natural condi-
tions can be singled out of the biosphere – they are called biomes. 
Meso-ecosystems, such as separate forest or grassland areas, swamps 
and lakes, in turn, can be singled out of the biomes.
The main function of an ecosystem is to maintain life 
continually, synthesising organic substances with complex molecular 
structure  –  such  as  cellulose,  sugars,  proteins  and  fats  –  from 
elementary inorganic substances, such as gases, water, salts. When 
organisms die off, they decompose back into elementary substances.
Notably, ecosystems cannot be described in spatial terms only, 
because there are no exact boundaries between them – unless nature 
itself has demarcated such boundaries, for example, the line between 
dry land and water. Usually the transition from one ecosystem to 
another is gradual, and the transition area is called an ecotone 
(Figure 4.7).  Therefore,  the  boundaries  drawn  on  the  ecosystem 
maps are quite relative – they often do not exist in nature.
Meadow ecosystem 
Forest edge ecotone 
Forest ecosystem