2.1 ECOLOGY, CLIMATE AND POLLUTION

THE THREE ES

Ecology

Ecology as a scientific discipline is relatively young, and only took importance in the second half of the 20th century1. The term “ecology”, from the Greek óikos, ‘house, household or family’, and lógos, ‘study of’, was first used by the German biologist Ernst Haeckel in 1866, who defined it as the “comprehensive science of the relationship of the organism to the environment”. The central principle of ecology is that each living organism has a continuing relationship with every other element in its environment.


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1 In the early 19th century, Alexander von Humboldt, a German naturalist, focused on the delicate balance of nature, where everything is interconnected. The idea was completely radical at the time, because for centuries it had been presumed that nature was explicitly created for our benefit and use.


Environment and ecosystem

The terms environment and ecosystem are often used interchangeably. However, the two terms differ dramatically in their ecological definitions:

  • an environment is the total surroundings of an organism, but it does not imply any ecological relationship between members;
  • an ecosystem is a biological community of interacting organisms and their physical environment. In other words, an ecosystem is the complex of abiotic and biotic factors acting on an organism or ecological community and determining its form and survival. More precisely:
    • Abiotic factors are all non-living components of an ecosystem: water, air, soil, temperature, light;
  • Biotic factors include all living things: plants, animals, fungi and bacteria.

Since the ecosystem is how living and non-living things in the environment interact as a unit, the biotic factors in an ecosystem are highly dependent on the abiotic factors. Anytime a “stranger” (another living thing) or an external factor (such as rise in temperature) is introduced into an ecosystem, it can be disastrous because the natural balance of interaction of the ecosystem can be distorted.

Types of ecosystems

Ecosystems can be roughly divided into:

  • terrestrial (forests, plains, mountains);
  • freshwater (lakes, rivers, wetlands);
  • marine (seas and oceans).

The total sum of all ecosystems is the biosphere, which can be subdivided into lithosphere (ground), atmosphere (air) and hydrosphere (water).

Biome

The relationships among different ecosystems lead to the concept of “biome”.
A biome is a large community of vegetation and wildlife adapted to a specific climate. There are five major types of biomes and some of them can be further divided into more specific categories:

  • aquatic (freshwater, marine);
  • grassland (savannah);
  • forest (tropical rainforest, temperate rainforest);
  • desert;
  • tundra (taiga).

The study and management of ecosystems are the most dynamic fields of contemporary ecology.1


DO

1 Do you know which science studies ecosystems?