We have a long tradition of research excellence at FSU as exemplified by the career of Fran James (see the tribute page). A big part of this success is due to the concentration of interests at the boundary of ecology and evolution, plus a commitment to interaction among faculty and graduate students. The work of many of us on density dependent selection is a good example of this interaction.

Density dependence and sperm competition in marine invertebrates

Faculty member Don Levitan works on the ecology and evolution of gametes in three species of sea urchins that live off the Bamfield Marine Station in British Columbia, which Don calls "the African savannah of invertebrates." Under natural spawning conditions, fertilization success of each urchin species is positively related to its abundance. However, under conditions where gametes of each species are equally common, the rarer a species is, the higher its fertilization success. This suggests that there is density dependent selection on fertilization success. Why don't all urchins fertilize at the same high rate? Perhaps there are disadvantages of eggs being too easily fertilized when sperm are abundant.

Don's most recent work suggests that these disadvantages may include the risk of developmental failure caused by more than one sperm penetrating the egg and the novel idea that eggs easily fertilized by their own species sperm may be susceptibility to fertilization by sperm of another species. As predicted from this idea, the rarest species show the highest rates of hybridization, and the most common the lowest rate. Don's work suggests some surprising and important ways that ecology and evolution interact, in this case because of population processes controlled by the abundance of organisms.


Despite the potential importance of density, ecological and evolutionary thinking has usually ignored the influence of density, presumably because it makes everything much more complicated. Other faculty with ongoing research in density dependent processes are Joe Travis, Tom Miller, Thomas Hansen, Fran James and David Houle.

Growth rates in dinosaurs

Greg Erickson is a functional morphologist who studies growth in both living and extinct reptiles. One of the themes of Greg’s recent work has been trying to understand how large dinosaurs got to be so big. To the uninitiated, this may seem a hopeless task, since we do not have the beasts around to study. Greg’s careful studies of the morphology of bone in living reptiles has revealed correlates of growth that are also visible in fossilized bone. From these, Greg can determine the relationship between age and size of extinct animals. The surprising result of this work is that dinosaurs grew much faster for their size than living reptiles. One Apatosaurus species is estimated to have packed on an astounding 5466kg/yr when about 10 years old!

In Greg’s view, "This is the most exciting time in the history of dinosaur paleontology. The bones are coming to life." (Nature 412:429, 2001). Greg’s work is an outstanding example of Florida State’s researchers efforts at understanding morphological adaptations. Other faculty engaged in such research are Scott Steppan, David Houle, Thomas Hansen, and Joe Travis.

Interactivity

In addition to these intellectual strengths, our group is marked by the ease of interactions across traditional boundaries that makes the group more than just the sum of its parts. We benefit greatly from our association with the School of Computational Science and Information Technology, which offers ready access to the most up to date computer facilities and, more important, to expertise applicable to computational needs in biology. The Florida State University Marine Lab, 45 minutes from the main campus, is always available to faculty graduate students alike.