International Encyclopedia of Systems and Cybernetics

Changes in a system and/or its environmental co-systems, as a result of reciprocal action, producing an evolutive feedback process.

According to R.N. ADAMS: "Co-evolution emerges when two or more sets of energy forms interact so that each becomes dependent for survival and evolution on the other. Co-evolution effectively blends the process of competitive Darwinian selection with the environmental selection of WALLACE" (1988, p.130). He adds: "The significance of co-evolution as a process, however, is that the trigger – flow interactions specifically create an interdependent reproduction among the participating dissipative structures. It interlocks a series of separately reproductive systems into a single interactive reproductive system" (p.133).

Co-evolution supposes permanent interactions between flow lines registering and transmitting information.

K.DE GREENE states: "Over time systems and environments co-evolve,… system's changes impact the external environment, and changes in this environment impact the system, For organic evolution as a whole, populations, species, genera and families maintain congruence or fit with their environment over considerable periods, Regulation and control stem from the system-environment relationship" (1988.p.251).

DE GREENE proceeds by explaining how, in human systems, the co-evolution interrelation between system and environment is modified by management. In fact, as observed by H.J. and I JERISON: "The organism, by its actions and preferences, partly selects the selection pressure which will act upon it and its descendants" (1980), This seems to have been true at least since the creation of an oxygen atmosphere by old and simple living beings.

Man however, having a more or less developed understanding of the relationship between his systems and their environment, tries (and is more and more able to do so) to modify it voluntarily, and even sometimes willfully, Moreover he does it mostly to obtain short term results in a supposedly positive sum game, ignoring long term results which may lead to "unchecked decay", in J. WARFIELD's words (1987. P.230).

Considering that, in E. JANTSCH words: "Coevolution is the generating principle of macrosystems, at least in the domain of life, but thereby a "vertical" dimension of coevolution is also implied by the coevolution of the macrocosmos and the microcosmos, the mutual enhancement in the evolution of macrostructure and microstructure" (1982. p.347), A better understanding of co-evolution, specially between man (the planetary super-predator) and the biosphere, is thus very important in order to avoid mega-disasters in the future of mankind. See for example the case of the Aral Sea, considered in systemic terms (CH. FRANÇOIS, 1989, p.1101-11).

St. KAUFFMAN observes that "… coevolutionary changes tend to occur in bursts followed by periods of quiescence" (1993, p.269), This rejoins S.J. GOULD and N. ELDREDGE theory about intermittent and punctuated evolution (1993).

Co-evolution is now actively researched, using adaptive automata. One example is the modelling of the predator-prey evolving interactions leading to adaptive transformations in the behavior and the internal controls themselves of the automata, This research takes place at the Ecole Polytechnique Fédérale de Lausanne (Switzerland) (D. FLOREANO, 2002, p.24-28)

An important aspect of co-evolution is that it also implies co-extinction, This phenomenon is generally overlooked, It is however becoming now very frequent. For instance, the destruction of enormous tracts of tropical forests leads, as a corollary, to the destruction of the habitat of a great number of vegetal and animal species, Many of them are condemned to extinction as a result.

→ Evolutionary robotics; Red Queen evolutive parable; Selection in populations (Combinatory); Selection principle (Loop)