Basic Evolution Strategies

The basic ES operates upon just one individual which is modified in an iterative process through the following operations  

An initial candidate solution (the first parent) is created either entirely at random or, as in the case of the GA, by using available domain-specific information about the solution space. 

A child solution is created by mutating all values in the parent in the manner outlined later. 

The fitness values of parent and child are found by testing their quality in the normal way. If the child is fitter than the parent, or is no worse, the child replaces the parent, and the parent is discarded otherwise the child is discarded and the parent survives. 

This process is repeated from step 2, starting with the surviving individual, until a solution of suitable quality is discovered or the maximum number of iterations is reached. 

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The strategy in a molecular dynamics simulation is conceptually fairly simple. The first step is to consider a set of molecules. Then it is necessary to choose initial positions of all atoms, such that they do not physically overlap, and that all bonds between the atoms have a reasonable length. Subsequently, it is necessary to specify the initial velocities of all the atoms. The velocities must preferably be consistent with the temperature in the system. Finally, and most importantly, it is necessary to define the force-field parameters. In effect the force field defines the potential energy of each atom. This value is a complicated sum of many contributions that can be computed when the distances of a given atom to all other atoms in the system are known. In the simulation, the spatial evolution as well as the velocity evolution of all molecules is found by solving the classical Newton equations of mechanics. The basic outcome of the simulation comprises the coordinates and velocities of all atoms as a function of the time. Thus, structural information, such as lipid conformations or membrane thickness, is readily available. Thermodynamic information is more expensive to obtain, but in principle this can be extracted from a long simulation trajectory. 

For these programs the problem is to create a structure which can transform raw materials sources into desired product streams. BALTAZAR uses basically a depth first strategy followed by evolution to discover its solution. AIDES on the other hand uses a breadth first solution, selecting the better alternatives by doing a one step look ahead at each decision step. 

In the case of selective neutrality—this means that all variants have the same selective values—evolution can be modeled successfully by diffusion models. This approach is based on the analysis of partial differential equations that describe free diffusion in a continuous model of the sequence space. The results obtained thereby and their consequences for molecular evolution were recently reviewed by Kimura [2]. Differences in selective values were found to be prohibitive, at least until now, for an exact solution of the diffusion approach. Needless to say, no exact results are available for value landscapes as complicated as those discussed in Section IV.3. Approximations are available for special cases only. In particular, the assumption of rare mutations has to be made almost in every case, and this contradicts the strategy basic to the quasi-species model. 

Buss DM 1994 The evolution of desire human mating strategies. Basic Books, New York... 

All these activities appear to be driven by the basic property of Hsp70s to interact with short hydrophobic peptide segments of protein substrates in an ATP-dependent fashion. The broad spectrum of cellular functions of Hsp70 proteins is achieved through three strategies. First, the amplification and diversification of hspK) genes in evolution... 

The basic strategy of plant biotechnology is a refinement of plant breeding and hybridization techniques practiced since the dawn of agriculture. The principle is that of natural selection and is the same that occurs in evolution. Plant breeders artificially select individual plants with desirable characteristics rather than letting the environment select the hardiest plants for survival. The desirable characteristics differ between individuals because each of different genes produces different inherited properties (phenotypes) in the new generation of plants. 

The biosphere as a whole behaves as if it has a peculiar evolutionary strategy We can and must talk about the evolutionary process of the biosphere by itself (V emadsky, 1991, p. 20 1997, p. 30). The evolution of the biosphere is determined by the three BGCP s stated above. According to the BGCP s, evolution goes in the direction of increasing the level of self-regulation and stability. One of the basic methods of... 

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