منابع مشابه
Reproductive isolation: Natural selection at work
The crucial step in the separation of two populations of a sexually reproducing species into two new species — speciation — is the acquisition of reproductive isolation between them. Such isolation ensures that they can evolve independently of each other, and so end up with radically different genotypes and phenotypes. This causes the biological world to be divided up into the discrete taxonomi...
متن کاملNatural selection. III. Selection versus transmission and the levels of selection. Journal of Evolutionary Biology
Natural selection increases inherited information about environmental challenge. Against selection, imperfect transmission reduces inherited information. Many problems in biology come down to understanding the relative balance between selection and imperfect transmission. A clear understanding of selection and transmission requires greater precision with regard to abstract notions such as inher...
متن کاملNatural selection. III. Selection versus transmission and the levels of selection.
George Williams defined an evolutionary unit as hereditary information for which the selection bias between competing units dominates the informational decay caused by imperfect transmission. In this article, I extend Williams' approach to show that the ratio of selection bias to transmission bias provides a unifying framework for diverse biological problems. Specific examples include Haldane a...
متن کاملMale development tracks rapidly shifting sexual versus natural selection pressures
Theory predicts that interplay between sexual and natural selection shapes phenotypic distributions over evolutionary time [1–3]. We show that this also significantly affects individual development. Developmental plasticity, whereby individuals vary their ontogeny in response to variation in the selection to be encountered upon maturity [4–6], has previously been demonstrated in response to sin...
متن کاملNatural product isolation.
Since the 1990s, interest in natural product research has increased considerably. Following several outstanding developments in the areas of separation methods, spectroscopic techniques, and sensitive bioassays, natural product research has gained new attention for providing novel chemical entities. This updated review deals with sample preparation and purification, recent extraction techniques...
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ژورنال
عنوان ژورنال: The Auk
سال: 1906
ISSN: 0004-8038,1938-4254
DOI: 10.2307/4070611