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Evolutionary Adaptations to Climate Change
Volume 10, Number 22: 30 May 2007

One of the grandest of catastrophes that climate alarmists contend will result from CO2-induced global warming - which they predict will be unprecedented in terms of both speed and level of temperature attained - is that many species of plants and animals will not be able to migrate poleward in latitude or upward in altitude fast enough to remain within temperature regimes suitable to their continued existence, and, therefore, that untold numbers of them will be driven to extinction. However, there are several things that could plausibly prevent this scenario from ever occurring.

Number one, the globe may not warm as predicted. Number two, the increase in the air's CO2 content may confer upon plants, and possibly animals as well, an ability to better cope with higher temperatures, as explained in considerable detail in our major report The Specter of Species Extinction. And third, according to the findings of an exciting new paper (Franks et al., 2007), climate change may rapidly impose natural selection on species and thereby cause genetically-based evolutionary shifts, which may enable them to successfully cope with the changing climate and thereby avoid what might otherwise prove an insurmountable problem.

So what, exactly, did Franks et al. do that led them to this intriguing conclusion? In a nutshell, and with respect to a specific real-world environmental change, they compared plant "phenotypic and fitness values of ancestral, descendant, and ancestral x descendant hybrid genotypes grown simultaneously under conditions that mimicked the pre- and post-change environment." The environmental change of which they took advantage, in this regard, was a switch from above-average to below-average precipitation in southern California (USA), which led to abbreviated growing seasons from 2000 to 2004, while the plant they studied was Brassica rapa L., more commonly known as field mustard.

Fortuitously, as they describe it, they had "collected B. rapa seed in 1997, before the drought, and then again in 2004 from two populations," a dry site and a wet site. Hence, they could grow - at the same time and under the same circumstances, in a new set of experiments - plants that had experienced extended drought conditions (descendants) and plants that had not experienced such conditions (ancestors), as well as hybrids of the two; and they could see if flowering times (FT) differed as would be expected from life history theory, which "predicts that the optimal FT in annual plants will be shorter with shorter growing seasons," as were imposed by the extended drought that occurred between the two times of their seed collecting.

This work revealed, in the researchers' words, that as predicted, "the abbreviated growing seasons caused by drought led to the evolution of earlier onset of flowering," such that "descendants bloomed earlier than ancestors, advancing first flowering by 1.9 days in one study population and 8.6 days in another," and they say that "the intermediate flowering time of ancestor x descendant hybrids supports an additive genetic basis for divergence." In consequence of these observations, they state that "natural selection for drought escape thus appears to have caused adaptive evolution in just a few generations," further stating that "abundant evidence has accumulated over the past several decades showing that natural selection can cause evolutionary change in just a few generations (Kinnison and Hendry, 2001; Reznick and Ghalambor, 2001)."

In discussing the significance of their findings, Franks et al. say their results "provide evidence for a rapid, adaptive evolutionary shift in flowering phenology after a climatic fluctuation," which "adds to the growing evidence that evolution is not always a slow, gradual process but can occur on contemporary time scales in natural populations," and, we would add (as was the case in this study), in response to real-world climatic changes.

Sherwood, Keith and Craig Idso

References
Franks, S.J., Sim, S. and Weis, A.E. 2007. Rapid evolution of flowering time by an annual plant in response to a climate fluctuation. Proceedings of the National Academy of Sciences USA 104: 1278-1282.

Kinnison, M.T. and Hendry, A.P. 2001. The pace of modern life II: from rates of contemporary microevolution to pattern and process. Genetica 112: 145-164.

Reznick, D.N. and Ghalambor, C.K. 2001. The population ecology of contemporary adaptations: what empirical studies reveal about the conditions that promote adaptive evolution. Genetica 112: 183-198.