Ecosystem can be defined as a structural and functional unit of biosphere including both organisms and abiotic environment, influencing the properties of each other and both necessary for the maintenance of life.
The term ‘ecosystem’ was proposed by Arthur Tansley
(imagine a forest ecosystem)
1. Consists of many species of plants and animals
2. Genetic diversity is very high
3. The sunlight is the energy source for autotrophs and this energy drives all biological cycles
4. Food chains are long and complex
5. Ecological succession takes place in a natural ecosystem over the period of time
6. Natural nutrient cycling ensures maximum and efficient cycling of nutrients
7. Productivity is extremely variable and depends on the environment. In tropical rainforest productivity is very high, but in deserts productivity is very low
8. High sustainability or naturally sustainable
Agricultural or artificial ecosystem
(imagine a paddy field)
1. Consists of a major crop plant (monoculture). Other species around are called weeds and farmer uses chemicals to destroy weeds.
2. Genetic diversity is very low and other plant species are removed by using weedicides
3. The sunlight is the ultimate energy source for autotrophs or crops but artificial fertilizers, manures and other nutrients are externally supplied to the soil.
4. Simple and often incomplete as other species are killed as pests or weeds
5. No ecological succession
6. Incomplete nutrient cycling. Harvesting of the crops removes large amount of nutrients from the soil making the soil less fertile each time.
7. Designed for high Productivity
8. Unsustainable as majority of fertilizers are from fossil fuels which are non-renewable and further adds to water pollution, bio magnification and other ecological disturbances.