The ecosystem
The
ecosystem is the set of species of a given area that interact with each other
and with their abiotic environment; through processes such as predation,
parasitism, competition and symbiosis, and with its environment to disintegrate
and become part of the energy and nutrient cycle. Ecosystem species, including
bacteria, fungi, plants and animals depend on each other. The relationships
between species and their environment, result in the flow of matter and energy
of the ecosystem.
The meaning of the ecosystem concept has evolved since its origin. The term coined in the 1930s, is ascribed to the English botanists Roy Clapham (1904-1990) and Sir Arthur Tansley (1871-1955). At first it was applied to units of various spatial scales, from a piece of degraded trunk, a puddle, a region or the entire biosphere of the planet, as long as they could exist organisms, physical environment and interactions.
More recently, it has been given a geographical emphasis and made analogous to the formations or types of vegetation; for example, scrub, pine forest, grassland, etc. This simplification ignores the fact that the limits of some types of vegetation are discrete, while the limits of ecosystems are not. The transition zones between ecosystems are known as “ecotones”.
Diversities alpha, beta and range. Robert Whittaker (1920-1980), an American ecologist investigating the succession and vegetation gradients, proposed three measures of ecosystem diversity: α, β, and γ. Alpha (α) is the diversity within an ecosystem that is generally described as the number of species. Beta (β) diversity includes the comparison of different ecosystems in environmental gradients, for example, in a mountainous area, in a coastal area. Beta diversity tells us how great the change of species from one ecosystem to another is. Gamma diversity (γ) refers to the total diversity of a region, that is, geographic diversity. In it the alpha diversities of several ecosystems are added.
The meaning of the ecosystem concept has evolved since its origin. The term coined in the 1930s, is ascribed to the English botanists Roy Clapham (1904-1990) and Sir Arthur Tansley (1871-1955). At first it was applied to units of various spatial scales, from a piece of degraded trunk, a puddle, a region or the entire biosphere of the planet, as long as they could exist organisms, physical environment and interactions.
More recently, it has been given a geographical emphasis and made analogous to the formations or types of vegetation; for example, scrub, pine forest, grassland, etc. This simplification ignores the fact that the limits of some types of vegetation are discrete, while the limits of ecosystems are not. The transition zones between ecosystems are known as “ecotones”.
Diversities alpha, beta and range. Robert Whittaker (1920-1980), an American ecologist investigating the succession and vegetation gradients, proposed three measures of ecosystem diversity: α, β, and γ. Alpha (α) is the diversity within an ecosystem that is generally described as the number of species. Beta (β) diversity includes the comparison of different ecosystems in environmental gradients, for example, in a mountainous area, in a coastal area. Beta diversity tells us how great the change of species from one ecosystem to another is. Gamma diversity (γ) refers to the total diversity of a region, that is, geographic diversity. In it the alpha diversities of several ecosystems are added.
