🗊Презентация Synecology or - Community Ecology лекция

Synecology or - Community Ecology

PLAN Biocenosis, biogeocoenosis and Consept of Ecosystem The State of the Species Under Various Forms of Relationship Trophic Structure of Biocenosis Food chain and trophic levels

Biocenosis is the community of populations of different species living and interacting in a given habitat (K. Mobius, 1877).

Ecosystem (ecological system) is the community of all populations of different species living on the common territory and interacting with their environment (A. Tensli, 1935).

An ecosystem comprises of two basic components i) Abiotic components and ii) Biotic components

The state of the species (population) under various forms of relationship is indicated by conventional signs “ – “an adverse effect, the body suffers harm, "+" - positive effect, "0" - no effect.

All biotic links can be divided into six groups: 1) "++"- mutually beneficial, symbiotic relationships. In this group the following is isolated: a) protocooperation when cooperation is beneficial, but not necessarily (pollination of various meadow plants by bees); b) symbiosis or inseparable links (lichens - fungi + algae, termites, and flagellate intestinal, which produce an saccharolytic enzyme); c) mutualism when a partnership is mandatory (cembretum, feeding by cedar seeds and spreading them).

2)“+0”- useful and neutral, or commensalism (shark and sucker fish).The followings should be distinguished in his group: a) sponger when the host food remnants are used (lion and hyena), b) commensal, c) tenant (orchids, lichens, mosses live in trees)

3) "0" - negative-neutral, or amensalizm (grass under the trees are suffering from severe shading). 4) "00 - neutral, or neutrality.

5) "+-"- useful and harmful; in this group the following may be distingushed: a) carnivorism, b) parasitism.

Trophic structure of biocenosis. Two major components: autotrophic and heterotrophic may be identified In biocoenosis or ecosystem. The autotrophic component ("self feeding") consists of green plants, which, by using solar energy synthesize organic matter of their cells (biomass) from the mineral components of environmental and is a major supplier of organic matter and related to its energy in biocenoses and ecosystems. In ecology, these organisms are called producers, while organic material they created is called primary production.

Heterotrophic component Heterotrophic component ("eating others") consists of organisms that derive their energy from food resulted from destructed organic matter, originally created by producers. Heterotrophic organisms are divided into two major groups: consumers and decomposers. Consumers are organisms that consume the finished organic matter (all animals, parasitic and humans).

Decomposers are heterotrophic organisms (fungi and bacteria) that subsist on dead organic matter and during their vital activities decompose it to inorganic. Thanks to them, the most important nutrients contained in dead organisms go back into the biological cycle and are repeatedly used in the metabolism of living organisms.

Joint effect of these three groups of organisms maintains a relatively endless circle of matter in ecosystems and biogeocenoses.

Food chains and trophic levels Matter and energy have been transferring through a series of organisms, and each previous organism supplies the subsequent one with raw material and energy in the form of food. Such chain of organisms is called a food chain, and each of its link - a trophic level

Energy flow and circulation of chemical elements in the ecosystem Any ecosystem consists of biotic and abiotic components, which closely interact with each other, exchanging matter and energy: living organisms consume matter and energy from the environment and give them back into the environment during the life-sustaining activity.

All living organisms appear to be consumers of food, that is of matter and energy. In the process of respiration of energy from its rich substances obtained from food releases. In process of breathing energy appears to release from energy-rich matter received from food.

Energy can be defined as an ability to do work. All living organisms can be considered as working "machines" that require a constant flow of energy from outside.

Living organisms can only use two forms of energy: photoenergy and chemical energy. All organisms are divided into phototrophic and chemotrophic depending on the energy source.

Organisms synthesizing all necessary organic matter by means of light energy (photosynthesis) belong to a phototrophic group, it includes all plants and cyanobacteria.

Chemotrophic organisms synthesize organic matter through the energy of chemical bonds of various substances. This includes all animals and bacteria.

Succession Any ecosystem undergoes changes both in time and space, in addition, changes are seen in the biocenosis structure, ecosystem structure and its productivity. Continuity of biocenoses occurring on the same territory as a result of impact of natural factors or human activities, is called succession (Latin word: successio means succeed).

Knowledge of the laws of ecosystem productivity has great practical importance, because the production of natural and artificial communities is the main source of food supply for humanity. Exact calculations of the energy flow and the extent of ecosystem productivity allow people to adjust them in the cycling of substances to achieve maximum production for human Knowledge of the laws of ecosystem productivity has great practical importance, because the production of natural and artificial communities is the main source of food supply for humanity. Exact calculations of the energy flow and the extent of ecosystem productivity allow people to adjust them in the cycling of substances to achieve maximum production for human