The hypothesis of adaptive radiation in evolutionary biology: hard facts about a hazy concept

Abstract

Adaptive radiation is one of the most emblematic concepts in evolutionary biology. However, the current lack of a consensual definition and the diversity of methods used to assess the extent and speed of adaptive radiation indicate the need for a reappraisal of this research field. In order to depict how adaptive radiations have been studied in recent years, we performed a scientometric assessment of 765 articles published between 2003 and 2012 in five journals known to serve a broad audience. From each study, we extracted and analyzed data relative to the taxon and geographical area investigated and to the methodological setup, and we categorized its outcomes and conclusions. This scientometry-oriented work allowed us to identify and discuss trends relative to the way research about adaptive radiations was carried out during the 10-year period starting in 2003. We then provided some recommendations for how to conduct a reliable study of a suspected adaptive radiation. The associated database resulting from our study will be a valuable source of information for biologists as they design a study or put their results in perspective. Our work may also inspire a critical assessment of the relevance of this pivotal concept in evolutionary biology.

Key questions and challenges in angiosperm macroevolution

“…Higher level diversification shifts in angiosperms have so far been dissociated from assessments of increasing phenotypic and functional diversity, which would be required to evaluate whether the detected diversification bursts can be considered as adaptive radiations (Givnish, ). Conversely, studies of adaptive radiations in angiosperms have so far been typically studied at comparatively narrow taxonomic scales, such as genera or families (Givnish, , ; Soulebeau et al ., ). Therefore, we currently lie at a crossroads at which a comprehensive analysis of deep‐time adaptive radiations in angiosperms, taking into account the pattern of nested diversification shifts, would be highly desirable.…”

Development of a Comprehensive Genotype-to-Fitness Map of Adaptation-Driving Mutations in Yeast

“…Adaptive evolution is a major driving force behind the observed phenotypic diversity in nature (Darwin, 1872; reviewed in Givnish, 2015 and Soulebeau et al, 2015), and is of key importance to many problems of biomedical interest, including cancer (Greaves and Maley, 2012; Korolev et al, 2014; Landau et al, 2013; Nowell, 1976) and the emergence of drug resistance (Davies and Davies, 2010; Palmer and Kishony, 2013; Pennings, 2012; Toprak et al, 2012). To further understand the process of adaptation, it is essential to obtain a large, statistically representative number of individual adaptive events and determine their fitness effects and molecular nature.…”

Revision of the tropical African genus Tetraconcha (Orthoptera: Tettigoniidae: Phaneropterinae) with the description of ten new species

“…Soulebeau et al 2015), and their biology is fairly unknown. However, that of Tetraconcha is a case of multiple speciation, not in islands or lake systems, but within a tropical forest ecosystem.…”

“…The emergence of many species from a common ancestor and the phenotypic diversification within the same environment deserve discussion. Evolutionary radiation is comparatively poorly studied in tropical rainforests of Central Africa, because the local biodiversity has been little documented (Soulebeau et al 2015). However, recent papers on Phaneropterinae of the Dzanga-N'Doki National Park have highlighted the co-occurrence of 8 species of the genus Catoptropteryx Karsch, 1890, 7 (Massa 2013, 2015, 2016, Hemp and Massa 2017.…”

“…Thus, if we consider the ecological differences in the forest canopy of Central Africa, speciation may have occurred in Tetraconcha species both by adaptive and exaptive radiation, sensu Soulebeau et al (2015) and Simões et al (2016). According to Simões et al (2016), adaptive radiation is the increase in the rate of speciation driven primarily by biotic factors in the form of adaptations associated both with ecological and morphological roles of individuals involved.…”