Biological responses to contemporary climate change are abundantly documented. We know that many species are shifting their geographic range and altering traits, including the timing of critical life history events such as birth, flowering and diapause. We also know from comparative studies of species found across the earth that a strong relationship exists between a species trait and the climatic conditions in which it is found. Together, these observations suggest that ongoing climate change may lead to evolutionary responses. Where examined, evolutionary responses have been uncovered in most cases. The effort needed to disentangle these genetic contributions to responses is substantial and so examples are few. In general, the documented evolutionary responses feature traits that are likely to alter responses to seasonal change or to change tolerance to environmental conditions. Currently available research provides hints that climate-mediated evolutionary responses are likely to be enormously diverse. It is clear, that the current presumption of many climate change scientists, that evolution can be safely ignored, does not have a basis in evidence.

Key Concepts:

• Biological responses to changing climate are well documented but the role of evolutionary mechanisms is typically unknown.
  
• Parsing the genetic from the nongenetic contributions to climate change responses is challenging.
  
• Evolution is rapid enough that natural selection is a plausible response to contemporary climate change.
  
• In the small number of cases where it has been evaluated, there is evidence supporting evolutionary responses to changing climate.
  
• Documented evolutionary responses to changing climate are diverse, but feature traits presumed to alter phenological responses or tolerance of changing climatic conditions.