I am a paleontologist and marine ecologist who studies invertebrate animals, that is, most of the different kinds of animals that have ever lived on Earth. I see my research as comparative:
- describing and explaining the history of life that actually can be observed as patterns in the fossil record, such as the changing forms of skeletons through time, or long-term trends in biodiversity,
- jointly studying processes that can only be inferred from fossils, such as the mechanisms of actual biological iinteractions, or the evolution of complexity that occurs at the different levels of organism and community, and
- comparing these with patterns and processes that can be seen in the living world, such as the development and life cycles of organisms, and the ecological processes of communities.
I first consider the broad context and importance of a problem, then try to find fossil and modern systems that are most amenable to empirical analyses, that provide complementary perspectives, and that offer sources of reliable data. This approach sometimes takes me in directions apart from the colonial animals I know and love best, cheilostome bryozoans. My past research projects have analyzed the evolution of different ways of growing in bryozoans; species competition between different bryozoan groups and how that affected their diversity and distribution; the diversification of flowering plants in the Cretaceous Period; the different historical stories told by fossil taxonomic richness and fossil abundance - how many species versus how many individuals; and how marine community complexity has increased over time.
Bryozoans remain at the center of my research vision, together with understanding the evolution and ecology of modular organisms in general. A biological module is part of an organism that exhibits higher within-part integration of processes – development, function, structure and so on – and lower integration with other relatively autonomous parts. In modular organisms such as higher plants and colonial animals like corals and bryozoans, the fertilized egg develops into a semi-discrete body that then makes more bodies like itself, but does so without sex.
This process and the consequent result of another level of variation within the organization of a genetic individual opens up a fascinating realm of questions: how do alternate forms (polymorphisms) evolve, yet have the same genotype?; what is the nature of individuality in biology?; or how do we measure change and extreme persistence over time at different levels in the biological hierearchy? These are the areas of my current research projects:
* Biological modularity, bryozoans, and the evolution of polymorphism
* Parts and wholes: the biological individual in the 19th century
* Living fossils and evolutionary stasis within the biological hierarchy.
I am also involved with graduate and undergraduate teaching and mentoring at the University of Illinois at Chicago and the University of Chicago. Graduate students interested in working with me are encouraged to apply to the University of Chicago’s Committee on Evolutionary Biology. Opportunities for postdoctoral students and undergraduate interns to work in my lab are also available through the Field Museum of Natural History.
Nyhart, L. K. and S. Lidgard. 2011. Individuals at the center of biology: Rudolf Leuckart’s Polymorphismus der Individuenand the ongoing narrative of parts and wholes. With an annotated translation. Journal of the History of Biology. Online first: http://www.springerlink.com/content/b1n5h32v51582385/
Lidgard, S., P. J. Wagner & M. Kosnick. 2009. The search for evidence of mass extinction. Natural History118(7): 26-32.
Dick, M. H., S. Lidgard, D. P. Gordon & S. F. Mawatari 2009. The origin of ascophoran bryozoans was historically contingent but likely. Proceedings of the Royal Society B-Biological Sciences276(1670):3141-3148.
Ostrovsky, A. N., D. P. Gordon & S. Lidgard. 2009. Independent evolution of matrotrophy in the major classes of Bryozoa: transitions among reproductive patterns and their ecological background. Marine Ecology-Progress Series 378:113-124.
Lidgard, S. 2008. Predation on bryozoan colonies: taxa, traits and trophic groups. Marine Ecology-Progress Series359:117-131.
Lidgard, S. 2008. Post-Paleozoic Ecological Complexity. Pp. 272-275 InMcGraw-Hill 2008 Yearbook of Science & Technology. McGraw-Hill Professional Publishing.
Wagner, P., M. A. Kosnik, & S. Lidgard. 2006. Abundance distributions imply elevated complexity of post-Paleozoic marine ecosystems. Science314:1289-1291.
Jackson J. B. C., S. Lidgard, & F. K. McKinney (eds.). 2001. Evolutionary Patterns: Growth, Form and Tempo in the Fossil Record. University of Chicago Press, Chicago. 344 pp.
Clarke, A. & Lidgard, S. 2000. Spatial patterns of diversity in the sea: bryozoan species richness in the North Atlantic. Journal of Animal Ecology 69:799-814.
Sepkoski, J. J. Jr., F. K. McKinney & S. Lidgard. 2000. Competitive displacement between post-Paleozoic cyclostome and cheilostome bryozoans. Paleobiology26:7-18. See also: Kerr, R. 2000.
Mc Kinney, F. K., S. Lidgard, J. J. Sepkoski, Jr., & P. D. Taylor. 1998. Decoupled temporal patterns of evolution and ecology in two post-Paleozoic clades. Science281:807-809.
Lidgard, S., F. K. McKinney & P. D. Taylor. 1993. Competition, clade replacement, and a history of cyclostome and cheilostome bryozoan diversity. Paleobiology19:352-371.
Crane, P. R. & S. Lidgard 1989. Angiosperm diversification and paleolatitudinal gradients in Cretaceous floristic diversity. Science246:675-678.
Lidgard, S. & J. B. C. Jackson. 1989. Growth in encrusting cheilostome bryozoans: I. Evolutionary trends. Paleobiology15:255-282.
Lidgard, S. & P. R. Crane. 1988. Quantitative analyses of the early Angiosperm radiation. Nature331:344-346. See also: Cleal, C. J. 1988.
Lidgard, S. 1986. Ontogeny in animal colonies: a persistent trend in the bryozoan fossil record. Science232:230-232.