XIII.2.1 Maintaining an apparatus for sexual reproduction is a costly matter for evolution

Meiosis, i.e. the process in which haploid sex cells are formed, is incomparably more complicated than mitosis.While mitosis usually takes from 15 minutes to 4 hours, the shortest meiosis in single-celled organisms lasts about 10 hours and, in multicellular organisms, requires at least 100 hours.

            Sexual reproduction requires the formation of specialized structures and mechanisms at all levels of organization of the living system, from molecular structures to complicated patterns of behaviour in animals.The formation of these structures and their maintenance in a functional condition through natural selection is a very costly matter – measured in terms of the basic evolutionary currency, i.e. the number of individuals eliminated in each generation by negative selection.

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The classical Darwinian theory of evolution can explain the evolution of adaptive traits only in asexual organisms. The frozen plasticity theory is much more general: It can also explain the origin and evolution of adaptive traits in both asexual and sexual organisms Read more
Draft translation from: Evoluční biologie, 2. vydání (Evolutionary biology, 2nd edition), J. Flegr, Academia Prague 2009. The translation was not done by biologist, therefore any suggestion concerning proper scientific terminology and language usage are highly welcomed. You can send your comments to flegratcesnet [dot] cz. Thank you.