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13.4. Balance in ecosystems

Balance in ecosystems

Ecosystems are self-regulating, so they can remain stable over time or evolve. There is an ecological balance that allows regulating, in a dynamic way, the different mechanisms of interaction between all the components of the ecosystem.

If environmental conditions are stable, living beings interact with their environment and the number of individuals of each species, although with fluctuations, is maintained over time. For example, there will not always be the same number of rabbits, it will vary depending on the predators, but remaining relatively stable.

Therefore, it is normal for a stable ecosystem to evolve as environmental conditions change due to natural causes. That wouldn't be a problem if it weren't for human action that upsets this ecological balance.

Interactive activity: Self-regulation of the ecosystem.

Factors for imbalances in ecosystems

Some of the triggers for imbalances in ecosystems are:


As a result of human activity, contamination of water, air, soil, etc., alters the balance of the environment.

The air pollution generates local effects such as the "heat island" of large cities, the smog or smog in some cities. It also has regional effects, such as acid rain that can cause damage to vegetation in areas further away from the polluting zone. Or global effects, such as the hole in the ozone layer, or the increase in the greenhouse effect, which is causing the average temperature of the Earth to have increased notably in recent decades, causing global warming.

This climate change produces alterations such as that the temperature increases between 1.5 and 6ºC and frequent heat waves appear, conditions of extreme drought, increased risk of fires, alteration of the hydrological cycle with hurricanes, tornadoes, with torrential rains and floods, appearance of tropical diseases, decrease in crop production, appearance of pests, melting of glaciers, rise in sea level with the problems of risk of flooding, soil and aquifer salinization, extinction of species that will not adapt to new conditions, and decrease in green areas and forests on the planet.

The contamination of water and soil will also affect the lives of living things in their environment.

Interactive activity: Global warming.

Interactive activity: Heating gases.

Species introduction

The introduction of species for livestock, fishing, hunting or exotic animals released when their owners have tired of having them as pets, compete with the autochthonous species that they displace and eliminate completely.

Book: Invasive alien species in Aragon.

Books: Manual of Good Practices to avoid the spread of Invasive Alien Species.

Video: Invasive species in Aragon.


The fires, whether natural or severely alter the habitat of living beings, affecting soil, water, air, biodiversity, contributing to deforestation. They seriously alter the balance of the ecosystem.


The deforestation is the disappearance of forests, fires caused by human activity or cutting down trees to exploit them for its timber, mining, to have new land for agriculture or construction of housing estates. The loss of the forest destroys the ecosystem.

Overgrazing would also alter the ecosystem.


By Jami Dwyer [Public domain], via Wikimedia Commons

Indiscriminate hunting and fishing

The hunting and poaching and indiscriminate makes most coveted species (for meat, ivory, skins, etc.) are at risk of disappearing and even extinction. Logically, the ecosystem is significantly altered.

How can we prevent the destruction of the environment?

The best way to prevent the destruction of the environment is to try to maintain the balance of the ecosystem, avoiding the triggers of imbalances in the ecosystem.

Some of the measures to be taken to avoid the destruction of the environment are the following:

  • As the consumption of fossil fuels for transport, heating, industry, etc., is the main cause of atmospheric pollution, it would be convenient to reduce its use, and move to an energy model in which renewable energies (solar, wind, biomass,…) Are more important than non-renewable ones.
  • Save energy by improving efficiency in vehicles, lights, heating, insulation, etc.
  • Preparation of reforestation plans to capture and reduce CO2 from the atmosphere.
  • Ecosystem protection measures, especially those that capture more CO2, such as forests.
  • International agreements in which all countries commit to work against climate change, such as Kyoto in 1997 or Paris in 2016.
  • There are also other measures that, although only applied on a personal level, can also help to maintain the environment, such as:
    • Turn off and disconnect electrical equipment that we are not using, such as the red light on the television.
    • Close the tap well, and when we use it, being careful not to waste water, such as when we brush our teeth with the tap closed, we shower instead of bathing, or we use devices in the toilet cistern that release more or less water depending on is needed.
    • Change the incandescent lights for led lights (light emitting diode), which allows us to save energy and money.
    • Use reusable cloth bags instead of plastic bags that take many years to disintegrate.
    • Recycle the waste that is produced in our house, car, etc.
    • Using public transport is cheaper and more ecological than going by car. In addition, if we go by bicycle, we improve our health and that of others.
    • Many more measures that surely you are coming up with.

Answer in your notebook

13.6.- Name five actions that you can do to improve the environment.


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