Ecosystems

An artificial ecosystem

The agro-ecosystem A typical example of an artificial ecosystem is a farmland or agro-ecosystem. This is a natural system altered by man through farming. It differs from a natural ecosystem for four reasons: 

• it is simpler, because the farmer gives priority to one type of plant only, fighting against all those animal and vegetal species that might damage it;
• the energy is supplied by man, through machinery, fertilisers, plant chemicals, selected seeds, farming practices
• the biomass (harvest) is removed when ripe. This makes the ecosystem an open system, i.e. one that depends on external sources to reintroduce fertilising substances, fit for feeding a new process of birth and development of organic matter (the plants). A natural ecosystem fertilises itself, instead, since the biomass remains in its original place
• the use of polluting substances, such as chemical fertilisers, parasite killers and other non-biodegradable chemicals, that build up in the ecosystem or disperse in the subsoil, sometimes seriously polluting underground water-bearing layers, seas and rivers.

A house is also a small artificial ecosystem. Items, food, solar energy, water, etc. come from the outside and the solid and liquid waste generated by human activities is disposed of outside. The same applies to the city. It depends on external sources for the supply of food, building materials and other resources it needs to develop, and disposes of its waste outside (dumping grounds and incinerators), that do not contribute, therefore, to the survival of the city as an ecosystem.