S1-3 Friday, Jan. 4 08:30 - 09:00 Functional Ontogeny and Morphological Evolution in Plant Reproductive Structures LESLIE, Andrew B.*; LOSADA, Juan M.; Brown University firstname.lastname@example.org
Form and function relationships are most often evaluated with regards to static functional roles, but these relationships may change over the lifetime of an organism or even its component parts. For example, flowers initially function in pollen transfer, but subsequently, as fruits, they protect and release seeds. Meeting such disparate demands often requires complex patterns of ontogenetic shape change, and in such organisms, any given form and function relationship could be thought of as a temporary stop along a larger developmental trajectory. Differences in specific developmental patterns among lineages may therefore play an important role in shaping and constraining form and function relationships and determining broader patterns of evolution. We explore these possibilities using conifer seed cones in the Pinaceae family, which are highly integrated structures that sequentially perform three basic functional roles: they facilitate wind pollination, they protect maturing seeds, and they disperse mature seeds. We combine anatomy, functional morphology, and phylogenetic comparative methods to show that cone phenotypes reflect a complex interplay between development and functional demands. Variation in developmental rate and timing alone can generate morphological diversity among lineages during some functional stages, such as at pollination. On the other hand, seed dispersal in Pinaceae occurs through a few mechanisms dictated by seed size, packing density, and dispersal agents, which constrain cone development patterns after pollination. Complex functional ontogenies are also present in many other plants, suggesting that interactions between developmental patterns and functional morphology may shape patterns of reproductive evolution across many lineages.