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).