The Extended Phenotype

The Extended Phenotype ( with the subtitle The Gene as the Unit of Selection, and later The Long Reach of the Gene ) is a 1982 published popular science fiction book of the British evolutionary biologist Richard Dawkins. 1999, a revised version was published with an afterword by the philosopher Daniel Dennett. The German -language edition was published in 2010 under the title The Extended Phenotype: The Long Arm of the genes. The concept of the Extended Phenotype, Dawkins considers as its main contribution to the theory of evolution.

Content

Dawkins extended the already developed in his earlier book The Selfish Gene idea that an organism constructed by his genes " survival machine " is to increase the chances of the genes to maximize their spread in the gene pool. In The Extended Phenotype, he treats of the subject from a more technical point of view, especially to the criticism of The Selfish Gene oppose.

Dawkins formulated in this book his thesis of the Extended Phenotype further. The influence of a gene could only be seen in context with its competing alleles (with different alleles of a gene have different effects on the phenotype, they could exist, for example, different alleles for coat color of an animal and the color is present by the genome of an animal copy allele determined ). In the classic sense of the phenotype is the sum of all externally observable characteristics of an individual, however, Dawkins wants to describe his definition of Extended Phentoype the sum of all the effects of a gene. Examples Dawkins leads to genes which are not ( with features such as height, hair color or eye color ) change the classical phenotypes, but control the behavior of an organism and its interactions with the environment. Another example would be a gene in a parasite that alters a certain behavior of its host, bringing the gene itself a survival advantage to ( namely by the host for the parasite advantageous behaves and this his genes may pass on increases - see example in links ). Consequently, Dawkins speaks of the " gene for proper beaver dams " in the beaver genotype, with very indirect and long-range effect. Dawkins sums up his thesis as follows:

"An animal 's behavior Tends to maximize the survival of the genes" for "that behavior, whether or not Those genes happen to be in the body of the Particular animal performing it. "

" The behavior of an animal tends to maximize the survival of the genes ' for' that behavior, whether these genes are now randomly located in the body precisely that animal that performs this. "

As in the "selfish gene" Dawkins tries in this book, the theory of evolution increasingly seen with the single gene in the center instead of organisms or even species. For, as he argues that it is ultimately the individual gene, which have success and remain in the gene pool or not - and this may be independent of species and breeds (so be certain very successful genes found in almost all living organisms ).