title: New insights into the species problem.
abstract: Historical opinions of the "species problem" are briefly reviewed, and four salient stages are recognized according to origin of species concepts. We propose that species is the unit preserving superior gene assembly and is maintained by specific mechanisms. Based on characteristics of plant evolution, we assume that understanding plant species may include three stages, i.e. morphological recognition stage, multidisciplinary verification stage, and illuminating mechanisms preserving superior gene assembly.
authors.affiliation: State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China. ephedra@ibcas.ac.cn
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.forename: ZheKun
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000818:Animals; D005075:Biological Evolution; D013045:Species Specificity