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How To Make Use Of Hydroids Behaviour

June 07, 2002

All organisms own somewhat puzzling integrity - functions of their parts are matched, growth and development are harmonic, movements are coordinated. In most cases, this integrity is provided by central neural system and humoral regulation. However, sometimes both CNS and humoral regulating system are absent. Ants colony works in amazing coordination without any central control, colonial organisms have no command centre. Their self-regulation mechanisms for many years were a subject of a detailed study by N.N.Marfenin, an assistant professor of the Chair of Zoology of Invertebrates at the Biology Faculty at Moscow State University. He concluded that it is the colony structure that provides a high degree of self-organisation: a number of similar organisms, which work independently and in sync. More than that, such organisation is much more effective than centralised one, because there is no extremely intensive information flow, no increasingly laborious data processing and, therefore, no control breakdowns.
        
Colonial hydroids are the best object to study non-centralised regulation on. These are branched organisms with transparent body, living in clear water - that`s why they are easy to observe. Hydroid looks like a hollow tree with hydrants - single colony elements - sitting on its branches and a trunk. Still, the colony is not a community, it is a united organism. It developed from a single cell, shares one body and transporting system. The development of different parts is in harmony and yet it has no central system.
        
All colony members are independent enough: they feed themselves independently, grow and branch if there is enough food or dissolve if not. They are united by the cavity inside the colony, so those hydrants, which catch no food, can feed too, although they grow slower. The food is transported by liquid inside the cavity. It moves because of shrinking of many pulsation centres, which act like a pump. The pulsation centres are not under general control; nevertheless, they work synchronously. They are all equivalent, the contribution of each individual into the whole system is not big and that is the main principle of non-centralised self-regulation. If several pulsators happen to shrink together, they push a strong stream of liquid to the neighbouring pulsator, what makes it to hold its own pulsation and shift the phase. One by one, all pulsators tune up to those working in accord. The more pulsation centres have coordinated their rhythm, the faster other will tune up. In this way, without any central systems, the colony reaches the most effective proportions, which corresponds best to the environment. The key to understanding the principles of integrity is not in singular processes, but in their cooperation.
        
This mechanism can have unrestricted usage in different biological, social and artificial systems. Let`s revert to the pulsation. The shrinking of many centres leads to different results depending on their order rather than their amount. In society the number of people is not as important as the coordination of individual activities. It would seem that reasonable directives from a centre should enhance the effectiveness of a team-work and the vitality of the collective itself. However, firm centralisation confines a personal initiative. This may result in two consequences. The first one is the process deceleration, because any initiative needs numerous agreements. The second is that an individual prefers to concentrate on secondary problems other than the main ones that also decreases the effectiveness of the planned cooperation. The optimal variant of self-organisation assumes the freedom of personal initiative provided that everyone follows the general rules of behaviour.
        
One more analogy. Nowadays neuroinformatics is of a great interest and one of its problems is creating of an artificial intellect, also called "neurocomputer". The base of this work is the principles of neural network - a community of equivalent elements, grouped together as a net. The hydroids` colony works alike. That`s why colonial hydroids may become a nice object to study the abilities of self-regulating systems. Non-centralised self-regulation of colony`s integrity is reached by the interaction of a number of many equivalent parts, which mostly work independently. From time to time, they correct the activity of each part to correspond the overall colony state, which mainly depends upon the amount of food and common environmental factors. According to Marfenin, sufficient autonomy, not a high level of interdependency, is the main condition for self-development and keeping the integration of complex systems.

Informnauka (Informscience) Agency