Abstract Detail

Paleobotanical Section

Larson-Johnson, Kathryn [1], Boyce, CK [1].

A functional design space for aerodynamic dispersal behavior based on wing morphology for all living and fossil plant propagules.

Seed dispersal is an important life history trait in plants, impacting local ecology as well as large scale macroecological and macroevolutionary processes. Understanding how plant traits influence dispersal processes is an integral step to understanding the dispersal potential of past plant populations and predicting dispersal patterns in current populations. One of the most prevalent types of dispersal is wind dispersal, having evolved many times across land plants. The two main modifications that enhance wind dispersal in seed plants are attachment of a plume or a wing. Although a plume is effective at increasing drag, it is effective only for small seeds. Wings, however, are effective over a broad range of seed sizes and can lead to complex aerodynamic behaviors, acting to slow descent and/or increase lateral displacement of falling seeds. Winged seeds are present in at least 160 extant families and ~800 genera. Even with this taxonomic diversity, a small subset of morphological characters is shared across the majority of all winged forms that can be used to summarize form and predict aerodynamic behavior(s). These characters were used to create a morphospace within which both extant and extinct propagule forms can be placed. The plotting of more than 250 extant genera resulted in clear clumping of taxa and well-defined unoccupied regions of the morphospace. These patterns suggest potential large-scale trends common to all winged propagules defined by optimization of biomechanical properties for the reliable performance of specific dispersal behaviors. Because areas of morphospace correspond to specific classes of aerodynamic behavior, the inclusion of fossils may allow for the prediction of aerodynamic behavior of extinct forms. Thus, broad evolutionary patterns of dispersal ecology may be traceable through the fossil record.

1 - Stanford University, School of Earth, Energy, and Environmental Sciences, 397 Panama Mall, Stanford, CA, 94305, USA

Keywords:
Morphospace
functional morphology
seed dispersal
winged propagule
propagule evolution
fossil record.

Presentation Type: Oral Paper:Papers for Sections
Session: 28
Location: Salon 13/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 9:15 AM
Number: 28006
Abstract ID:1019
Candidate for Awards:None