Ecological speciation

‘cological speciation’ is a mode of speciation in which adaptation to different environments causes populations to diverge and develop reproductive isolation from each other. This classical hypothesis has matured in the field of evolutionary ecology with the accumulation of new empirical data. A full understanding of the mechanisms by which ecological speciation leads to biological diversification requires the synthesis of ideas from many different disciplines, including evolution, ecology, and genetics. In the present review, we introduce the definition of ecological speciation and discuss factors leading to population divergence, geographic conditions, differences among taxa, and isolating barriers unique to this type of speciation. We then compare ecological speciation with alternative ‘non-ecological’ modes of speciation. Throughout the review, we identify the weak points of the current concept of ecological speciation, and propose future challenges in the study of the mechanisms of biological diversification.