2012四川高考.doc

The relationship between sexual selection and speciation(Xiong ying 1373950176@) Biological sciences 1102 class, biological science and engineering school ，Shaanxi University of Technology 1 Introduction The intriguing relationship between sexual selection and speciation has sparked an increasing number of papers in recent years that have attempted to draw connections between the two processes. These include a myriad of theoretical and empirical studies, as well as several influential reviews (e.g. Price, 1998; Panhuis et al., 2001, Kirkpatrick and Ravigné, 2002; Ritchie, 2007; Maan and Seehausen, 2011). In particular, many researchers have speculated on whether sexual selection can lead to speciation, either alone, or in conjunction with ecological processes. Such speculation is tempting in part because of the obvious differences in secondary sexual characters that often exist between closely related species. Indeed one of the earliest and most influential of all sexual selection models, Lande’s (1981) paper “Models of speciation by sexual selection on a polygenic trait” centered its title on the role that sexual selection may play in speciation. What, however, is the evidence of a causal relationship between sexual selection and speciation? It turns out to be surprisingly ambiguous. Many have attempted to address a relationship by comparative studies, a process that can be problematic because of both methodological concerns and the fact that the presence of sexual selection is inferred by proxy (Kraaijeveld et al., 2011). Kraaijeveld et al. (2011) point out that these studies only sometimes support a correlation between sexual selection and speciation, and using a meta–analysis find only weak support for a relationship across multiple datasets. A large number of individual experimental studies have also examined various aspects of the intersection of sexual selection and speciation, but it is often unclear what would constitute a true test of the role of sexual