Biocoenosis

A biological community ( altgr. βίος bios ' life ' and κοινός koinos together ') is a community of organisms of different species in an identifiable habitat (biotope ) and location. Biocenosis and biotope together form the ecosystem.

The creatures of a community communicate with each other in numerous interactions, are influenced by abiotic environmental factors and act on them back ( biozönotischer nexus ). The result is a biological or ecological balance. These relationships are examined in the Biozönologie (or Biozönotik ), a sub-discipline of ecology. One also speaks of Synecology - in contrast to autecology, in which the ecological relationships of individual species are considered.

The term was coined in 1877 by biocenosis Karl August Möbius, who described the common living on an oyster bank organisms as a " community " or " Biocönose ".

Characterization of biological communities

Depending on the focus of typing biological communities can be characterized by different taxa:

• A Phytozönose ( plant community ) is formed by the living together in a habitat plants of different species. In plant sociology plant communities are described for characterizing phytocoenoses, each characterized by character types with the same or similar claims on their site. Example: The rock rubble society of high mountains with the Rundblättrigem Täschelkraut ( Thlaspi rotundifolium ) is defined as the plant community Thlaspietea rotundifolii.
• A Zoozönose (Animal Collective) formed by living together in a habitat animals of different species (for example, the animal community of the Ngorongoro Crater ). Although in certain habitat types typical zoocoenosis occur, which could similarly be described as plant communities as characteristic species combinations, a similar formalized system in zoology is not in use.
• A microbiocenosis (microbes society ) constitutes the entire occurring in a microhabitat microorganisms represents the claims and metabolic pathways of the individual species can be very different, as the metabolic end product of a microorganism may represent the substrate for another microorganism.

Coenosis can stand as a generic term for Phytozönose and Zoozönose. Accrued partial communities of certain systematic order are commonly called Taxozönosen (example: Beetles of Buchenwald, mosses in rivers, birds an agricultural landscape ). The name by which each treated group, for example Avizönose for birds is possible, but seldom used. Summing organisms different systematic rank in partial habitats together (eg all organisms in decaying wood, all Koprophagen on feces of ungulates, all the inhabitants of the forest canopy in a tropical rain forest ) one speaks rather of Synusien.

The types of biological communities occupy according to the niche theory different ecological niches. Kinds of similar lifestyle ( example: all seeds eater ), exploit the same resource in a similar way are grouped into guilds.

Interactions between living things

We distinguish interactions between the members of a species ( intraspecific interactions ) and interactions between members of different species ( interspecific interactions ).

These interactions may affect the survival and reproductive ability of the individual ( fitness) and thus also on the development of the population density of a species in an ecosystem (see Population Ecology ).

On the relations include food, transport and protective relationships.

Possible effects of the interactions between two species on the population density:

• The trivial case where two species in the same habitat influenced not mutually exclusive, is very difficult to prove due to the complexity of ecosystems. He may be given if, for example, collect migratory birds with different ecological demands on the hike overnight at a rest area.
• A type takes advantage of the relationship, the other is not affected. Depending on the degree of dependence is different per -, para- and Metabiosen. Examples: Karpose, commensalism.
• Symbiosis: Both species benefit from the relationship ( symbiosis in the narrower sense, see mutualism ).
• Antibiosis: One type is damaged without the other type would have an advantage or disadvantage of it. For example, if heavy hoofed animals often go the same way, destroy them on their changing vegetation ( Amensalismus ).
• Both types are determined by the relations disadvantaged ( competition).
• A kind of benefits from the relationship, but at the same time harms the other Art Examples: predation, parasitism.

Stability

Biological communities represent a dynamic system that is constantly changing. Stay individuals and numbers of species over a longer period constant, the ecosystem is in balance. Changes in environmental conditions or species composition can, however, change a biocenosis quickly. This can compensate for changes better than species-poor to a widespread hypothesis is that species-rich ecosystems, they are more stable. The relationship between species richness and stability in ecological research, however, is controversial, for example, because there are counter-examples - very species-poor, but this stable communities.

Step into an ecosystem succession on different biological communities, it is called succession.

Changing affiliations

A kind of can - especially when it performs hikes - be nationals of different biological communities. So are young eels in the sea as willow leaf larvae are planktonic and later as elvers to Nekton Nekton and finally to a river or lake. Belonging to a biocenosis can therefore change during the various stages of development. For example, most cancers are as nauplius or zoea larvae part of the plankton, live as adults but on or in the ground waters and thus belong to the benthos. The situation is similar in many mussels and polychaetes

Biocoenotic basic principles

• The more diverse the ecological niche of a biotope, the more species-rich biocenosis (see tropical forests ).

• The more removed the abiotic factors of a biotope from the physiological optimum of most species, the fewer species, but also in individuals richer the ecosystem, the organisms of these communities are often highly specialized. (Salt lakes, heavy metal lawn ).
• The slower and continuous, the living conditions have changed in a biotope, the more species-rich is its biocenosis. ( Coral reefs ).

Evolution

The intensive interactions, especially the food relations, fostering the evolution and thus the adaptation of species to the biotic and abiotic factors in an ecosystem. From co-evolution is when two species in a mutual adjustment shall be made to each other (eg, system pollinators - flower). Coevolution promotes specialization of species and thus tends to increase the species diversity of biological communities.

Paleontology

In a Thanatocoenose ( " grave Community"), are embedded and fossilized the remains of organisms of a biocenosis.