Earth Science: Biology – Ecology – Ecosystems
Ecosystems are dynamic systems of inanimate (abiotic) and animate (biotic) components. They are interconnected through material and energy cycles.
Abiotic factors include air, soil, climate, and food requirements; the biotic factors are plants, animals, fungi, and bacteria All ecosystems on Earth make up the biosphere.
Earth Science: Biology – Ecology – Biocenosis and Biotope
The totality of living beings, including animals, plants, and microorganisms of an ecosystem is referred to as biocenosis; the spatially delineable environment with its typical, ambient conditions is called the biotope.
A biocenosis, or ecological community, is characterized by the number, abundance (average number of individuals of a species in an area), and areal distribution of species. The species inhabit different ecological niches, so species diversity is primarily dependent upon the number of ecological niches in an ecosystem; the higher that number is the more species can avoid competition with other species.
In a biocenosis, there is generally constancy in specimen density within local species. In an ideal case, natural material cycles are table, so that a dynamic equilibrium is established. If this is disturbed, the overall character of the ecosystem changes and it can be partly or entirely destroyed. Moreover, since ecosystems are interrelated, the equilibrium of adjacent ecosystems can also be affected.
Biotopes, the delineated environments of a biocenosis, display a more or less uniform state or condition, and can be distinguished from each other. Similarly, a habitat refers to the location where a particular species occurs.
The organisms in an ecosystem can be categorized according to their function into producers, consumers, and destruents (decomposers). The producers, or manufacturers, include all organisms that are capable of photosynthesizing.
These are principally plants, but also include autotrophic bacteria. They synthesize organic compounds (biomass) from inorganic sub-stances, which are then used as food by all heterotrophic organisms within the ecosystem.
The consumers, or users, include all planteaters that are directly reliant upon the photosynthetic capability of producers (primary consumers), as well as small and large meateaters (secondary and tertiary consumers).
The destruents include bacteria and fungi, which reduce dead organic sub- stances to water and carbon dioxide, as well as into minerals. These are then available again as nutrients.
BASICS
SUCCESSION AND CLIMAX The stable, final state of an ecosystem is called the climax condition. Succession is the state of changes in the ecosystem that can lead to a climax community.