Spore Size Evolution

In collaboration with Bill DiMichele (Smithsonian NMNH), Carol Hotton (Smithsonian NMNH),  Patricia Gensel (UNC Chapel Hill), and Andrew Leslie (Stanford), the lab's biggest new project (post-quarantine) will be examining spore size evolution during the Devonian. The ultimate goal of this work is to achieve a better understanding of the initial evolution of heterospory (see here for more details on heterospory). We plan to combine multiple datasets to determine when, where, and in what kinds of depositional environments large spores first appear. 

Understanding the ecological and biological factors favoring the initial evolution of large spores (and accordingly, heterospory) is challenging, because plant communities in the Early and Middle Devonian (419-383 mya) were unlike those of today. Specifically, this time period saw a major change in land plant size and ecological complexity, from small herbaceous species characteristic of the Early Devonian, to forest communities of large woody trees by the end of the Middle Devonian. The rise of complex forests, with presumably increased competition for resources, may have favored investment in larger spores and heterospory. However, testing any relationship between spore size evolution and shifts in plant ecology requires a more detailed understanding of the basic temporal, lithological, and geographic patterns in spore size evolution than is currently available. It is our goal to provide this framework.