5 - Genetic Variability and the Nature of Microevolutionary Responses to Elevated CO2

Abstract

This chapter addresses how rising CO2 affects the component processes of natural selection—namely, the expression of phenotypic variation in fitness, the degree to which this variation is heritable, and genetic covariance of other traits with fitness—and focuses on the direct effects of CO2 rather than the indirect effects mediated by climate change. An understanding of the impact of elevated CO2 on the component processes of selection is of central importance in predicting which traits are likely to be affected and how the selection of these traits may ultimately affect population-, community-, and ecosystem-level processes. Recent empirical work has documented substantial intraspecific genetic variation in plant-growth responses to elevated CO2, which raises the issue of selective responses to elevated CO2 in plant populations. Genetic correlation structure is also likely to be altered due to a disruption of the functional integration of plant development.