Niche

Niche or an organism's ecological niche is the smallest unit of a specific habitat or ecosystem that is inhabited. It is the complete range of physical and biological conditions in which organisms of a species can live and the way the organisms use such conditions. A niche really is the position any local population of a species takes in a local ecosystem. It is as if the environment or ecosystem is the residence and the ecological niche is the organisms many jobs or actions that make it very competitive within that environment.

Take for instance the Tomato plant and its ecosystem. It consists of mineral-rich soil, plenty of water and plenty of sun. It's ecological niche, or jobs are photosynthesis, as well as absorption of water and important minerals from the soil it is planted in.

Evolution and Ecological Niches
Evolution is driven by the ability for all organisms and plants to attain their own environmentally isolated roles within daily routines. From an individuals genetic change (mutation) being sexually reproduced (natural selection) it propagates throughout a given population. The more acutely honed the environment, population and selection paradigm becomes through the process of different sizes of populations developing independently from parent populations and individuals creating ecological niches, the more radical the evolution will be.

This process is called adaptive radiation.

Related References

 * Niche by Alexei Sharov 1997, Virginia Tech's Entomology Department

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