Essay - Ecology/caspian Sea Community Concepts the Concept of Community is One...

Ecology/Caspian Sea

Community Concepts

The concept of community is one that has defied definition for centuries, even among individuals in the field of ecology. While all agree that a ***** *****volves a group of species together in the same area, and ***** those species must co-exist and interact competitively for resources, ***** actual definition ***** a community concept is v*****ried (Allen, 1998). However, there are two viewpoints that appear most often in today's ***** of community, and this section will discuss those viewpo*****ts individu*****y.

The first concept of ***** is that ***** the "d*****crete unit" by Frederic Clements. According to this concept, a community is like a superorganism, where the ***** of ***** area are interconnected ***** parts ***** a body (Ricklefs, 2001). E*****ch species in the ***** has co-evolved, or evolved along with ***** another ***** such ways as to enhance the independent functioning of one *****. As this holistic view describes, these ***** species are understood in the sense ***** community only ***** the contributions each ***** makes to the dynamics of the entire system (Allen, *****). It is precisely ***** contributions, made by independent species in an interactive way through co-evolution, that allow communities to develop.

*****' "discrete unit" ***** of comm*****y describes a closed community. In other words, ***** discrete unit or community is distinct ***** its self, and h***** very specific boundaries, ***** ecotones. Distributions ***** ***** *****in t*****e community are coincident, rather than independent (*****, 1998). ***** is ***** through succession, or the orderly sequence of changes in communities, that a stable community is possible (Allen, 1998).

The second concept ***** community ***** derived from Henry Gleason's idea of the loose assembly of species (Ricklefs, 2001). This ***** revolves around ***** ***** that a community is an association of species whose requirements and adaptations to the *****a allow *****m to live with one another under specific conditions. Under ***** idea, the species that cohabitate do so by coincidence, ***** than co-adaptation (Allen, 1998). Gleason's concept ***** one of an open community, as well, where no community has boundaries.

Under Gleason's community concept, a community's structure and functions are only expressions ***** the interactions between ***** *****, not due ***** an organization of ***** species. In this ***** community, then, distributions ***** species are ***** of one *****, ***** *****out definition (Allen, 1998). They do not exist out of necessity, as in the "distinctive unit" concept, but rather out of coincidence.

Regardless of which concept is assumed, there are some agreed upon *****s ab***** biological communities. For example, in any *****, ***** or open, ********** co***** with ***** another, and are l*****ked to one ***** by their interactions, giving any concept ***** community both a special and a functional definition. Further, any ecological effect or evolutionary effect on the ***** affects all species, since all ***** interact ***** one another.

In the Caspian Sea, there are many spatial areas that could be considered ***** communities. In particular, the area of the southern Caspian is home