Population, Species, Biocenosis AN INTEGRATING VISION

The population, the species and the biocenosis are presented and analysed as systemic units which really exist, work and evolve, having reciprocal relationships with the abiotic environment at the same time, only in ecosystems. No population or species exists in isolation. From the point of view of the theory of systems, the population, as a group of organisms which can be found in a biocenosis, is a common subsystem for the two systems, i.e. the biocenosis and the species. The population also has a double function: an ecological one in the biocenosis and a genetical one within the species. All the populations and the species can be considered as ecological units because their organisms have ecological adaptations, and the populations are structural parts in the biocenosis and have ecological functions in the process of production, consumption and decomposition of organic matter in the ecosystems, which is an aspect scarcely shown so far. At the level of the populations there are also genetical functions, particularly natural selection which generates new ecological adaptations (and others) as new species.