Leslie, Andrew .
Using Function to Interpret Patterns in Conifer Cone Evolution.
Understanding how the functions that seed plant reproductive structures perform influences their morphological evolution can provide insights into the evolution of reproductive biology as well as the critical evaluation of morphological characters that are used in phylogenetic analyses. Conifers, a group with a long evolutionary history and separate pollen-producing and seed-producing structures, are an ideal group to study in order to investigate how the different functions reproductive structures perform may have driven broad patterns in their morphological evolution. Analyses of discrete morphological character data, combined with continuous morphometric data, from fossil and extant conifers show that pollen-producing structures (which perform a more limited set of functions than seed-producing structures) exhibit morphologies similar to modern taxa earlier in conifer history than seed-producing structures, and that seed-producing structures show a more diverse range of morphologies through time. This study suggests that the greater number of functions the seed-producing structures perform may have resulted in greater morphological diversity. The differences in morphological diversity between pollen-producing and seed-producing structures may also be due in part to changes in the growth of the seed-producing cone in response to increasing biotic interactions through time. Additionally, the reduction in the number of parts in the conifer seed scale through time may be related to the increased importance of growing tightly imbricated structures that protects seeds from potential predation.
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1 - University of Chicago, Department of Geophysical Sciences, 5734 S. Ellis Avenue, Chicago, Illinois, 60637, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Superior A/Cliff Lodge - Level C
Date: Monday, July 27th, 2009
Time: 9:30 AM