How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

Evolution or Phenotypic Plasticity: How to Survive Climate Change
Volume 17, Number 24: 11 June 2014

In mankind's quest to ascertain the consequences of potential global warming for earth's many animal species, two potential means for enabling their salvation have come to the fore: evolution and phenotypic plasticity. In the first case, Merila and Hendry (2014) write that "adaptive evolution occurs when the genetic constitution of a population changes as a consequence of natural selection," which begins to operate when some process in an animal's environment - such as the warming of air, soil or water - begins to exert some degree of stress on the animal. Much the same thing occurs in the case of phenotypic plasticity; but in this case the animal's response is not genetically based.

In a "super" review of the findings of eleven regular review articles that appeared in the same issue of Evolutionary Applications, Merila and Hendry (2014) summarize some of the other reviewers' findings. First of all, they note that "although a huge number of studies have found evidence of climate-associated phenotypic trends (e.g., Parmesan and Yohe, 2003), only a few have used the best methods for inferring genetic versus plastic change, adaptive versus non-adaptive responses, and specific environmental drivers." But they are still able to report that "instances of confirmed genetic change do occur in birds and mammals, and especially in terrestrial plants and insects." In contrast, they say that "considerably more studies have found evidence for plastic contributions," as highlighted by the results of Teplitsky and Millien (2014).

Overall, the two "super" reviewers say "it seems safe to conclude that plasticity often makes a strong contribution to phenotypic trends associated with contemporary climate change." But they also note that "plenty of examples certainly do exist of genetically based adaptation to local temperature differences on similar time frames." And as one example, they report that "the contemporary evolution of temperature-dependent development has been shown for salmonid fish populations introduced to new thermal environments (e.g., Haugen and Vollestad, 2000) and for amphibian populations subject to pond warming as a result of beaver activity (Skelly and Freidenburg, 2009)," all of which findings can be viewed, in their words, as first steps "toward progress in improving our understanding of the relative roles of genetic change and plasticity in mediating adaptive organismal responses to changing climatic conditions."

Sherwood, Keith and Craig Idso

Haugen, T.O. and Vollestad, A.L. 2000. Population differences in early life-history traits in grayling. Journal of Evolutionary Biology 13: 897-905.

Merila, J. and Hendry, A.P. 2014. Climate change, adaptation, and phenotypic plasticity: the problem and the evidence. Evolutionary Applications 7: 1-14.

Parmesan, C. and Yohe, G. 2003. A globally coherent fingerprint of climate change impacts across natural systems. Nature 421: 37-42.

Skelly, D.K. and Freidenburg, L.K. 2000. Effects of beaver on the thermal biology of an amphibian. Ecology Letters 3: 483-486.

Teplitsky, C. and Millien, V. 2014. Climate warming and Bergmann's rule through time: is there any evidence? Evolutionary Applications 7: 156-168.