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• Assuming that phenotypic variation affects the outcome of interactions with other organisms and the environment.
• Through the process of natural selection, there will be a refining of the genetic variation that is the basis of that phenotypic variation. At a very mechanistic level this genetic variation effects gene function and one way is through expression of individual genes which combine to form complex phenotypes.
• Populations become adapted to the local conditions as this process is iterated over generations.
• But how does this process work in the face of rapid climate change like we’re seeing today?
• Climate change will shift the local forces of natural selection. As local conditions change, what was the native flora may no longer be adapted to the new conditions. These native flora have several options, 1)quickly evolve, given sufficient sources of variation, certain genotypes may survive 2) quickly change their range to follow the conditions to which they are adapted 3) be lost because they can’t tolerate the conditions or they are out competed by any number of plants that are better adapted.
• The highest risk of course is that the new conditions will be conducive to an increasing number of invasives that are moved around intentionally or accidentally by human activities. But invasive species have also challenged our classic understanding of adaptation through natural selection….

Since Helianthus anomalus, like many invasives have established by one or only a few genotypes it seems that in all of these scenarios in response to rapid climate change, the genetic make-up of the surviving populations (whether invasive or native) will have gone through what is considered a genetic bottleneck. And by that I mean the amount of genetic variation present in the population will be severely reduced which should restrict the potential for populations to continue to respond to changing climates!

 

• Going back to our classic version of how evolution by natural selection occurs, it should be useful to consider how epigenetic effects might contribute to this process that is dependent on genetic variation.
• Epigenetic processes may provide a second inheritance system, very similar to the genetic inheritance system. But, unlike genetic variation, epigenetic variation may be altered directly by ecological interactions (physical environment or biotic) and therefore provide an additional, accelerated pathway for evolutionary change.
• Considering the rapidly changing local conditions that are resulting from global climate change this second more rapid inheritance system may be extremely important for adaptation.
• This triangle of effects: genetic variation, epigenetic variation and variation in gene expression, and their effects on phenotypic variation, have been the major themes in ecological genetics and genomics as I have explored how plants respond to novel and changing environments.
  

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