How humans influence the Earth, our inherent dependence on it, our relationship to each other, and our connection to all life — no discipline meaningfully illuminates such concepts as biology does. Biology unveils the substance that serves as the blueprint for our own construction, but also demonstrates how that substance is life’s very deepest homology. Which is to say, biology offers explanation at multiple levels: first by establishing patterns and investigating their causal processes, and then by providing proximate and ultimate causes for observed patterns and processes. This dual causality — the proximate functional ‘how’ and the ultimate evolutionary ‘why’ — is of particular importance to biological sciences; the ‘why’ being the stuff that gives the ‘how’ consequence.
Yet hundreds of studies demonstrate that students hold tenacious misconceptions regarding the evolutionary principles necessary for recognizing levels of biological explanation, and that formal instruction does little to address such misconceptions. How do these misconceptions form? Why are they so resistent to formal training? How does one come to understand evolution, and what does that entail? One part of my disseration is concerned with uncovering the logic behind students’ understanding of natural selection in an effort to wrestle with such questions.
View my talk given at the Midwest Ecology and Evolution Conference, 2021
DiSessa, A. A. (1993). Toward an epistemology of physics. Cognition and Instruction, 10(2-3), 105-225.
Mayr, E. (1961). Cause and effect in biology. Science, 134(3489), 1501-1506.
How do flowering plants — stationary organisms with no behavior — control what pollen (sperm) fertilizes their ovules? While the vast majority are hermaphrodites that harbor the potential for self-fertilization, not all flowering plants fertilize themselves. Instead they exhibit enormous variation in the anatomical and physiological features related to sexual reproduction, making them the most reproductively versatile group of organisms on the planet.
Outside of anatomical features, many plants possess invisible genetic mechanisms that allow them to recognize and reject their own pollen. These plants are self-incompatible (SI). Several SI mechanisms have been uncovered with varying genetic and molecular underpinnings, and we know that some of these mechanisms are shared across many distantly–related plant families. In fact, the evolution of SI is thought to play an important role in the enormous success of flowering plants as a group. Traits that influence mating patterns and the genetic relatedness of mating pairs affect the amount and the distribution of genetic variation in space and in time, with broad consequences for the evolutionary pathways available to organisms. What kind of consequences? How does SI (or its absence) influence the distribution and diversity of flowering plants generally?
To answer these questions, we first need to know something about how SI is distributed across all flowering plants — we must first determine the observed pattern. From there, we may evaluate what processes are responsible for generating such a pattern. Currently we know very little about how many SI mechanisms exist, the phylogenetic distribution of SI mechanisms, or even which species possess an SI mechanism and which do not. Thus, one part of my dissertation is concerned with uncovering the distribution of SI in two of the largest flowering plant families: the bean family (Fabaceae) and the orchid family (Orchidaceae), which account for 16% of all flowering plant species.
View my poster presented at the Annual Meeting for the Botanical Society of America, 2018
Barrett, S. C. (2013). The evolution of plant reproductive systems: how often are transitions irreversible?. Proceedings of the Royal Society B: Biological Sciences, 280(1765), 20130913.
Franklin-Tong, V. E., & Franklin, F. C. H. (2003). The different mechanisms of gametophytic self–incompatibility. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 358(1434), 1025-1032.