Global patterns of speciation and diversity

• Published in: Nature (London) 2009-07, Vol.460 (7253), p.384-387
• Main Authors: de Aguiar, M. A. M., Baranger, M., Baptestini, E. M., Kaufman, L., Bar-Yam, Y.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Barriers; Biodiversity; Biological and medical sciences; Biological diversity; Biological evolution; Disorders of Sex Development; Evolutionary biology; Extinction, Biological; Flowering plants; Fossils; Fundamental and applied biological sciences. Psychology; Gene mutations; General aspects; Genetic Speciation; Genetics of eukaryotes. Biological and molecular evolution; Genotype; Geography; Haploidy; Humanities and Social Sciences; Influence; letter; Marine invertebrates; Models, Biological; multidisciplinary; Mutation; Mutation - genetics; Origin of species; Population Dynamics; Rare species; Reproduction - genetics; Reproduction - physiology; Science; Science (multidisciplinary); Sexual Behavior, Animal; Sexual reproduction; Songbirds; Speciation; Species diversity; Synecology; Time Factors
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature08168

The road to biodiversity The 'neutral' theory of biodiversity, first expounded by Stephen Hubbell in 2001, successfully predicts many of the observed patterns of ecological biodiversity by adopting the simplifying assumption that each individual and each species behaves in the same way, independent of species interactions or history. A new variant of the neutral theory is presented in this issue, adding components that factor in sexual reproduction, mutation and dispersal. The new model simulates reality on many levels, and compares well with real data sets, from shrubs in Panama to fossil mammals in Kansas. The results also show that biodiversity can arise without specific physical barriers — a situation resembling the phenomenon observed in heavy traffic flows, where traffic jams can form for no apparent reason other than there is traffic. The question of why biological diversity is spread in characteristic patterns is perhaps the biggest problem in ecology. In recent years, the 'neutral theory' of biodiversity has modelled the distribution of species in a very simple way, without reference to species interactions or history. Sexual reproduction, mutation and dispersal are now introduced to the simulation of populations; the resulting predictions correlate well with real data sets. In recent years, strikingly consistent patterns of biodiversity have been identified over space, time, organism type and geographical region 1 , 2 . A neutral theory (assuming no environmental selection or organismal interactions) has been shown to predict many patterns of ecological biodiversity 2 , 3 . This theory is based on a mechanism by which new species arise similarly to point mutations in a population without sexual reproduction. Here we report the simulation of populations with sexual reproduction, mutation and dispersal. We found simulated time dependence of speciation rates, species–area relationships and species abundance distributions consistent with the behaviours found in nature 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 . From our results, we predict steady speciation rates, more species in one-dimensional environments than two-dimensional environments, three scaling regimes of species–area relationships and lognormal distributions of species abundance with an excess of rare species and a tail that may be approximated by Fisher’s logarithmic series. These are consistent with dependences reported for, among others, global birds 4 and flowering plants