Natural selection mechanism

Of the many metaheuristics available, evolutionary algorithms (EAs) have become very popular because of their ease of implementation and high effectiveness. EAs are based on an emulation of the natural selection mechanism (Goldberg, 1989). EAs are particularly suitable for solving multi-objective problems because of their ability to handle a set of solutions in a simultaneous manner, and their capability to deal with problems of different types, without requiring any specific problem-domain information (e.g., derivatives) (Deb, 2001). 

As already mentioned in Chapter 1, the eompositional changes, the major shifts, that took place between cold- and warm-blooded vertebrates, and the maintenance of the compositional patterns so formed cannot be accounted for by any explanation only or essentially relying on stochastic processes. This led us (Bernard and Bernard , 1986a) to propose a natural selection mechanism acting on the genome phenotype. 

Genetic Algorithms are an artificial intelligence technique inspired on the evolution theory. This technique is based on artificial natural selection mechanisms and genetics, and represents the solutions as an optimization problem. Biology shows how adaptations to the environment are transmitted to offspring by means of individual... 

In addition, naturally growing plants resist plant pathogen and Insect attack because resistance develops over time via natural selection (35). Also, most natural and crop plants have, as a part of their basic physical and chemical makeup, a wide array of mechanisms that help them resist pest attack. These Include chemical toxicants, repellents, altered plant nutrients, hairiness, thorns, and diverse combinations of these (35). 

We should note once again the general mechanism by which resistance appears in target species is natural selection. Many factors may accelerate or slow this process a growth in frequency or number of resistance alleles their dominance, ability to penetrate, and expressivity their interaction with various genes the speed with which generations are replaced the number of individuals in each generation the character of the reproductive system (sexual or asexual) and a host of other factors [113]. 

What made evolution flow might also have proved contentious had Darwin not also oiled his way around problems of mechanism. Darwin s sixth edition of Origin ultimately accommodated evolution to Lamarck s principle of psychic anamnesis and the inheritance of acquired characteristics, the laws of nature as prescribed by a deity, and God s eternal wisdom. Darwin only hoped that natural selection would be seen to play some part somewhere along the way of descent with modification . 

A core assumption of ultra-Darwinism is that if not all, then most observed characters must be adaptive, so as to provide the phenotypic material upon which natural selection can act. However, what constitutes a character - and what constitutes an adaptation - is as much in the eye of the beholder as in the organism that is beheld, as Gould and Lewontin pointed out in their famous paper on spandrels (Gould and Lewontin, 1979). Natural selection s continual scrutiny does not give it an a la carte freedom to accept or reject genotypic or phenotypic variation. Structural constraints insist that evolutionary, genetic mechanisms are not infinitely flexible but must work within the limits of what is physically or chemically possible (for instance, the limits to the size of a single cell occasioned by the physics of diffusion processes, the size of a crustacean like a lobster or crab by the constraints... 

The role of antiproliferative effects of an activated defense reducing the next generation of herbivores compared with the straightforward action of toxins or feeding deterrent metabolites in the evolutionary arms race is still under discussion. The proposed mechanism suggests natural selection at the group level,... 

Abstract Resistance to modern antibiotics is currently a major health concern in treating infectious diseases. Abuse, overuse, and misuse of antibiotics in treating human illness have caused the pathogens to develop resistance through a process known as natural selection. The most common mechanism of resistance to -lactam antibiotics is the production of /3-lactamases, which destroy -lactam antibiotics before they reach the bacterial target. Over the last two decades, combination therapy involving treatment with a -lactam antibiotic and a /3-lactamase inhibitor has become very successful in controlling -lactamase-mediated bacterial resistance. Currently available inhibitors like... 

Replacement of coded L-amino acids with d-amino acids is a common strategy in peptide drugs. However, it must be stressed that D-amino acids are far from unknown in nature and can even be found in animal peptides, where they are usually formed from L-amino acids by a post-translational reaction [208], It appears that this mechanism increases the structural diversity of products that can be synthesized from one gene, thus increasing the scope of evolution by natural selection. In other words, the incorporation of D-amino acids into peptides is a strategy discovered by evolution and rediscovered by chemists. 

Evolution . .. main mechanism is by natural selection acting on accidental genetic modifications devoid of intentionality. The finding of molecular biology can leave no doubt in this respect. 

Clearly this means a complete rejection of the fundamental Darwinian principle of common descent. Also, he rejects mutation and natural selection as the mechanisms that produced species. Is this view also contrary to the universality of biochemistry, and in particular the monophyletic origin of life, to which most biochemists today would subscribe Probably yes but of course if one assumes an absolute determinism, then the laws of chemistry and physics would produce the same products at each different start. This goes against the notion of frozen accident and the unique origin of the genetic code. So, there was never a time on Earth with only one kind of species, and the development of species was parallel rather than sequential. Of course all these ideas are substantiated by arguments and data - for these, the reader should refer to the original sources. 

The biological treatment of contaminated water is prehistoric. One could say that the treatment is a natural process of recycling. Part of the system involves the accumulation of water in ponds and lakes followed by the growth of carbon-eating microorganisms. The latter is a process of natural selection. In modem times, this model is used to treat water contaminated by the concentration of populations and industrial development. While the mechanism is the same, modem systems are set up to handle increasingly large loads. 

The argument so far has been highly abstract and general, because it is intended to be valid fora number of selection mechanisms. It applies to the biological theory of natural selection, where it first arose, but also to the theory of economic competition, the theory of unconscious motivation and the theory of computer chess programs. Before I consider the first two in more deuil, I shall digress for a moment and say a few words about the relation between biology and the social sciences. 

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