Ecological niche?

Question

Ecological niche?

Answer 1

This is potentially a question requiring a very long answer, however to be brief, there are two parts to your question:

1. Ecology = the study of species, their interactions with other organisms and their environment;

2. Niche = a specific role or function.

Therefore, an ecological niche is the specific role or function of a species with regard to the nature of its interactions with other organisms and their general environment.

Niches are dynamic, as much as the environment changes and genetic evolution occurs. Niches may be broad or narrow potentially indicating a generalist species or a more specialised one respectively. The more specialised a species is and hence the more narrow its niche is, the greater potential susceptibility it has to changes in the environment such as climate, human disturbance or the introduction of new organisms at any scale.

While displaced species may be forced to extinction, the niche they occupied may or may not continue to exist. Species that have become specialised are often implicated in symbiotic relationships with other organisms. The removal of one of the species is likely to result in demise of the other. But for more generalist species, should they be removed from an environment, it is likely the niche they formerly occupied will be filled by one or more other species with which it originally may have competed. In such a case the niche will be redefined by the new species that fulfil the roles of the former.

A niche therefore is a very human approach to defining an environment by trying to break it down into pieces like a puzzle. The problem is that the pieces will change shape over time. An ecological niche is therefore a snapshot view of the way in which a species interacts with its environment, this will change either in response to natural or human induced events. An excellent example is House Sparrows. They wouldn't be called by such a name if they hadn't developed a liking for houses and the urban environment. Clearly species like this have evolved to fill an expanded niche that includes nesting and foraging in urban environments, something relatively new to "nature". Other such species include Asian House Geckos, House Mouse and the many species you might see on a daily basis in any of the world's big cities.

Answer 2

Each animal or plant has their own individual role in their community.  Take honeybees for example. Their jobs are to pollinate- without their role in the ecosystem, seeds wouldn't be possible.  Coyotes keep the populations of rabbits and other rodents in check.  

  Trees provide the role of creating shade for animals and homes for birds and squirrels. (in some forests).

  If one animal goes extinct, there often will be no substitute that will cover their job.  That is why it is so important to keep organisms from going extinct.