- •Variant – 1
- •Variant – 2
- •Variant – 3
- •Variant – 4
- •Variant – 5
- •Variant – 6
- •Variant – 7
- •Normalization of the harmful substances, disposal with sewage.
- •Variant – 8
- •Variant – 9
- •Normalization of the harmful substances, disposal with sewage.
- •Variant – 10
- •Variant – 11
- •Variant – 12
- •Variant – 13
- •Variant – 14
- •Variant –15
- •Variant – 16
- •Variant – 17
- •Variant – 18
- •Variant – 19
- •Normalization of the harmful substances, disposal with sewage.
- •Variant – 20
- •Variant – 21
- •Global Warming
- •Variant – 22
- •Variant – 23
- •Variant – 24
- •Normalization of the harmful substances, disposal with sewage.
- •Variant – 25
- •Variant – 26
- •Variant – 27
- •Variant – 28
- •Variant – 29
- •Variant –30
Variant – 6
Commensalism and Amensalism
Types of communications and mutual relations between organisms
Alive organisms are definitely connected to each other.
Types of relations between organisms. Influence of one species on another can be positive, negative and neutral. Thus different combinations of types of influence are possible. There are neutralism, mutualism, commensalism, predatoriness, parasitism, a competition, amensalism.
Commensalism
A symbiotic relationship in which one organism derives benefit while causing little or no harm to the other.
Amensalism
Definition of Amensalism : between two species involves one impeding or restricting the success of the other without being affected positively or negatively by the presence of the other. It is a type of symbiosis. Usually this occurs when one organism exudes a chemical compound as part of its normal metabolism that is detrimental to another organism.<br><br> The bread mold Penicillium is a common example of this; penicillium secrete penicillin, a chemical that kills bacteria. A second example is the black walnut tree, which secrete juglone, a chemical that harms or kills some species of neighboring plants, from its roots.
A symbiotic relationship in which one organism is harmed or inhibited and the other is unaffected.
Succession
Translational changes are changes in biocenosis, finally, resulting in change of this community by another. Succession is a consecutive change of biocenosis (ecosystem), expressed in change of specific structure and structure of community. Successions are desertification of steppes, overgrown of lakes and formation of bogs, etc.
Depending on the reasons caused change of biocenosis, сукцессии are divided into natural and anthropogenous, autogenious and allogenious.
Сукцессия of Siberian darkneedle forests (fir-cedar taiga) after devastating forest fire
Numbers in rectangular are vibrations in duration of passage of сукцессии phases (in brackets term their termination is specified). The biomass and biological efficiency are shown in unspecified scale. (Curves reflect the qualitative and quantitative parties of the process.) (Rejmers, 1990.)
Natural succession occurs under action of the natural reasons which have been not connected with activity of man. Anthropogenous succession is caused by activity of the person.
Hard-Vainberg law
Genetic structure is a relationship of various genotypes and equilocal genes in the community. Totality of genes of all community species is called genofund. The genofund is characterized with frequencies of equilocal genes and genotypes. Frequency of equilocal genes is its share in all totality of equilocal genes of the given gene. The sum of frequencies of all equilocal genes is equal to unit.
According to Hard-Vainberg law, relative frequencies of equilocal genes in population are remained constant from generation to generation. Hard-Vainberg law is fair, if following conditions are observed: 1) the population is great; 2) in community free interbreeding is carried out; 3) there is no selection; 4) there are no new mutations; 5) there is no migration of new genotypes in community or from community.
The long and directed change of genetic structure of community, its genofund is called the elementary evolutionary phenomenon. Without change of the community genofund, evolutionary process is impossible.
The factors changing genetic structure of community are following:
1) Mutation is a source of new equilocal genes appearance;
2) Unequal capable of living of species (species are subjected to action of selection);
3) Not casual interbreeding;
4) Drift of genes is a change of equilocal genes frequency, which are casual and independent of selection action (for example, flashes of diseases);
5) Migrations are outflow of available genes and (or) inflow new ones