Sunday, November 4, 2012

What is an ecosystem?

An ecosystem can be defined as:

"a system formed by the interaction of a community of organisms with their environment."

To understand the exact meaning of this phrase, let’s examine each part separately.

Firstly, a ‘system’ is “a set of connected things or parts forming a complex whole”. In this case, the connected things are of course the community of organisms and their environs and the complex whole is – you guessed it – an ecosystem.

Secondly, a “community of organisms”... A ‘community’ is a technical ecological term meaning “an assemblage of two or more populations of different species occupying the same geographical area”. What this means is that a community is a mixture of organisms of different species, in the same place and therefore interacting in some way. Interactions between organisms in a community include predation, parasitism and competition for food and other resources.

Thirdly, “their environment” consists of all the environmental factors that influence organisms, this includes how hot and cold it gets in the environment, the availability of water, the pH and gradient of the soil, humidity et cetera. Factors such as these are not alive, and thus are known as ‘abiotic’ factors; conversely, interactions mentioned above such as competition are ‘biotic’. Things get complicated when you consider that these factors are to a greater or lesser extent determined by the organisms themselves, for instance dense forest will retain water better than adjacent grassland because the trees block the sunlight so less water evaporates and buffer wind so the humid air is carried away more slowly.

The way that nutrients move between organisms and their environment through their interactions in an ecosystem creates nutrient cycles, often also considered parts of an ecosystem.

An ecosystem is often treated like a discrete unit, in practice, organisms do of course move between ecosystems constantly, it is sometimes difficult to say where one ecosystem ends, and another begins.

In summary, an ecosystem can be thought of as all the organisms in a location, their interactions with each other and their environment.
What is an ecosystem?

An ecosystem can be defined as:

"a system formed by the interaction of a community of organisms with their environment."

To understand the exact meaning of this phrase, let’s examine each part separately.

Firstly, a ‘system’ is “a set of connected things or parts forming a complex whole”. In this case, the connected things are of course the community of organisms and their environs and the complex whole is – you guessed it – an ecosystem.

Secondly, a “community of organisms”... A ‘community’ is a technical ecological term meaning “an assemblage of two or more populations of different species occupying the same geographical area”. What this means is that a community is a mixture of organisms of different species, in the same place and therefore interacting in some way. Interactions between organisms in a community include predation, parasitism and competition for food and other resources. 

Thirdly, “their environment” consists of all the environmental factors that influence organisms, this includes how hot and cold it gets in the environment, the availability of water, the pH and gradient of the soil, humidity et cetera. Factors such as these are not alive, and thus are known as ‘abiotic’ factors; conversely, interactions mentioned above such as competition are ‘biotic’. Things get complicated when you consider that these factors are to a greater or lesser extent determined by the organisms themselves, for instance dense forest will retain water better than adjacent grassland because the trees block the sunlight so less water evaporates and buffer wind so the humid air is carried away more slowly.

The way that nutrients move between organisms and their environment through their interactions in an ecosystem creates nutrient cycles, often also considered parts of an ecosystem.

An ecosystem is often treated like a discrete unit, in practice, organisms do of course move between ecosystems constantly, it is sometimes difficult to say where one ecosystem ends, and another begins.

In summary, an ecosystem can be thought of as all the organisms in a location, their interactions with each other and their environment.

No comments:

Post a Comment