Chapter 6 the theory of competition 145 6 the definition and classification of competition has been at the centre of ecological and evolutionary research since darwin; the theory of competition is almost a proxy for ecological theory. Competition can be defined from many angles, but the simplest and most general definition is that of an interlocking barrier between organisms (same or fae) produced under the control of the same factor (resources, combinations of resources, predators, etc.) ( wang kong, zhang dae yong 1996). The role of competition can also be classified from several angles. First, it is classified in terms of biota. Competition is a negative effect among organisms; then, when these organisms belong to the same species, they are called intra-species competition; when they belong to different species, they are called inter-species competition. Inter-species competition is the subject of competition theory. When it comes to competition, if not specifically mentioned, it should be considered as inter-species competition. Previous studies of intra-species competition have been carried out mainly at the population level; the effects of competition are expressed in the characteristics of “average individuals” such as birth, mortality or net growth rates. This simplification ignores the differences between individuals within stocks and the various structures within stocks. If we talk about intra-plant competition in relation to inter-plant competition, then there is a degree of legitimacy and necessity for this omission; but if we are specializing in intra-species competition, individual differences and stock structure within the species will not be negligible. And, as we will see in 6. 73, the proper understanding of competition and coexistence between species requires consideration of the internal structure of the species. The structural characteristics of the population are diverse, such as sex ratio, age structure, genetic structure, individual size class, etc. The study of stock behaviour under competitive conditions, taking these structures into account, is a new trend in recent years of intra-crop competition research ( wang kong, zhang dae yong 1996), but this chapter is no longer limited to space. The second classification of competition is the classification of competition into exploitative and disruptive competition. Harnessing the use of competition among living individuals who use common limited resources is achieved through the intermediary of resources. All competing individuals are reducing the availability of resources, while the decline in resource availability affects all individuals and reduces their suitability. There is no direct behavioural confrontation between individuals, whose main characteristic is the reaction of competing individuals to resource levels. Disruptive competition affects one individual by direct behavioural confrontation. The essence of such interference among individuals is also the use of resources, and thus disruptive competition is a potential competition for resources. We know that the availability of resources, their quantity and their spatial scope are inextricably linked; if an individual can preserve a certain area of space, he or she can have a certain amount of resources alone. This would avoid depletion by the co-use of resources by other individuals. This direct confrontation for competition and space is a proactive form of competition that has evolved in order to win the use of resources. Such interference can occur at three levels between individuals, sub-groups and species. Third, competition can be divided into symmetrical and asymmetrical competition. As noted above, competition is a negative effect on each other of the biological individuals that are shown under certain factor control and can be shown by the symbol "-" and therefore competition is mutual
