Tangled Bank hypotheses

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Tangled Bank hypotheses A set of hypotheses, proposed by G. Bell in 1982, which emphasize the importance of the spatial heterogeneity found in a complex environment (i.e. a Tangled Bank) in the maintenance of sexual reproduction. The fitness of a genotype that is successful in one location but less so in another may not be inherited by its offspring. It may be advantageous, therefore, for siblings to disperse at random into microsites nearby, regardless of the local success of the genotype. It is argued that this allows greater penetration of microsites than would be possible for clones of a parthenogenetically reproducing organism and reduces competition among siblings. The ‘Tangled Bank’ is taken from the opening sentence of the final paragraph of Darwin'sOrigin of Species: ‘It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us.’