Joseph (Joe) Williams, Ph.D
Department of Ecology and Evolutionary Biology
Office: Hesler 341
Visit our lab website. (http://www.bio.utk.edu/williams/)
I study the evolution of development of plant reproduction, especially with respect to the origin of flowering plants. Projects in my lab generally involve some aspect of how and why unique aspects of angiosperm reproduction originated and what their consequences were for diversification of the group. We study developmental processes in living representatives of what are considered ancient lineages of flowering plants to reconstruct (infer) ancestral states of reproductive traits and ontogenies. At present, we are focused on the progamic phase, which is the life history period between pollination and fertilization and, it turns out, a focal point of evolutionary innovation. One interest here is in the evolution of mate recognition patterns. Are there early forms of pre-zygotic self-recognition systems in extant basal angiosperms? If so, what developmental modifications were involved in the evolutionary shift from a presumably ancestral pattern of post-fertilization mate recognition (present-day gymnosperm pattern) to the typical angiosperm pattern that is often entirely pre-zygotic? Answering that question involved understanding how angiosperm pollen tube growth innovations originated and how they were involved in the evolution of the carpel and its closure (“angiospermy”). Work in our lab suggests that the novel angiosperm pattern of pollen tube growth and development was a fundamental enabler of the evolution of flower morphologies and reproductive cycles.
Recent Selected Publications
Taylor, ML, Macfarlane, TD and JH Williams. 2010. Reproductive Ecology of the Basal Angiosperm Trithuria submersa (Hydatellaceae). Annals of Botany In press.
Williams, JH, RT McNeilage, MT Lettre and ML Taylor. 2010. Pollen tube growth and the pollen tube pathway of Nymphaea odorata (Nymphaeaceae). Botanical Journal of the Linnean Society 162: 581-593.
Taylor, MLT and JH Williams. 2009. Consequences of shifts in pollination syndrome for post-pollination biology in an ancient aquatic family. International Journal of Plant Sciences 170: 584-598.
Williams, JH. 2009.Amborella trichopoda (Amborellaceae) and the evolutionary developmental origins of the angiosperm progamic phase. American Journal of Botany 96: 144-165.
Williams, JH. 2008. Novelties of the flowering plant pollen tube underlie diversification of a key life history stage. Proceedings of the National Academy of Sciences, USA105: 11259-11263.
Arias, T and JH Williams. 2008. Embryology of Manekia naranjoana (Piperaceae) and the origin of tetrasporic, sixteen-nucleate female gametophytes in Piperales. American Journal of Botany 95(3): 272–285.
Friedman,WE, Madrid, E and JH Williams. 2008. Origin of the fittest and survival of the fittest: relating female gametophyte development to endosperm genetics. International Journal of Plant Sciences 169(1): 79-92.