Evolutionary dynamics of biodiversity

Gradients of resource availability and of temperature can increase, decrease, or have no effect on biodiversity, and biologists are only just beginning to try to figure out the conditions that determine the specific effects. Our lab is currently engaged in several projects to further investigate the effects of resource availability on biodiversity.

Long-term stationary phase Escherichia coli

With the help of microbiologist Steve Finkel, we study the evolutionary and ecological dynamics of genetic diversity in long-term stationary phase Escherichia coli cultures.
Patterns and mechanisms
Species diversity of plants and animals may increase or decrease along productivity and temperature gradients. Our research is using laboratory cultures of E. coli., to understand mechanisms controlling diversification and its maintenance along these gradients (e.g., Stevens et al. 2007).
Effects of Environmental Color
The world is variable, and yet we rarely study the effect of that variability. This pattern of temporal variability of an environmental factor can be characterized as the "color" the pattern, deriving designations of white, blue, red referring to spectral density distributions that are flat (random white noise), or skewed toward higher frequencies (blue = relative uniform) or toward lower (relatively correlated red noise). Reddened patterns of environmental variability ("pink" spectra) are thought to be relatively common in natural systems. Further, their seem to be systematic differences in different environments, for instance, with marine environments relatively red compared to terrestrial environments. In collaboration with Joel Cohen (Columbia U), Owen Petchey (Sheffield U), and Steve Finkel (USC), we have been using long-term stationary phase Escherichia coli to investigate the effects of variation in environmental color on population dynamics and the evolution of competitive ability in Escherichia coli (Cohen et al. in review).