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The Evolution of Plants ... Right Before Our Very Eyes (1992-2010)

Paper Reviewed
Thomann, M., Imbert, E., Engstrand, R.C. and Cheptou, P.-O. 2015. Contemporary evolution of plant reproductive strategies under global change is revealed by stored seeds. Journal of Evolutionary Biology 28: 766-778.

Writing in the Journal of Evolutionary Biology, Thomann et al. (2015) report the evolution of some important reproductive traits of the annual cornflower plant (Centaurea cyanus) that they discovered in a common garden experiment, where they germinated stored seeds that had been collected in 1992 from the same location where they had collected the other seeds that they germinated together with them in 2010, when and where warmer springs and indices of pollinator decline had recently been reported. And in so doing, they found that compared to the ancestral plants of 1992, plants of the descendant 2010 population (1) flowered earlier, (2) produced larger flower heads, as well as (3) more peripheral florets than the plants of 1992.

Employing techniques used by Spitze (1993), Koskinen et al. (2002) and Whitlock (2008) to differentiate between phenotypic traits and neutral genetic differentiation in their study, the four French scientists were also able to evaluate the role of natural selection as opposed to genetic drift in the trait differentiations they observed in their experiment. And this part of their study suggested, as they describe it, that "evolution, and not only plasticity, is a component of short-term population responses." In addition, they determined that "natural selection has contributed to the evolution of some reproductive traits of the cornflower," while further noting that "such evolutionary changes are consistent with climate warming and pollinator decline," which two phenomena were known to have occurred simultaneously in the part of the world where they conducted their study.

Although evolution by natural selection has historically been considered to operate over very long timescales, some plants of today are successfully employing it over a mere few decades. And that is wonderful news suggesting that Earth's plants will continue to respond to whatever changes in climate the future may bring.

Koskinen, M.T., Haugen, T.O. and Primmer, C.R. 2002. Contemporary fisherian life-history evolution in small salmonid populations. Nature 419: 826-830.

Spitze, K. 1993. Population structure in Daphnia obtusa - quantitative genetic and allozymic variation. Genetics 135: 367-374.

Whitlock, M.C. 2008. Evolutionary inference from Q(ST). Molecular Ecology 17: 1885-1896.

Posted 11 August 2015