Bringing Together the Living and Dead: Integrating Extant and Fossil Biodiversity in Evolutionary Studies
Feild, Taylor S. .
Extant basal angiosperms; pitfalls or springboards for re-greening Early Cretaceous ecophysiology?
THE flowering plants – angiosperms – appeared during the Early Cretaceous period and within ~30 Myr dominated the species composition of many floras worldwide. Emerging insights into the phylogenetics of development and discoveries of early angiosperm fossils are shedding increased light on the patterns and processes of early angiosperm evolution. However, there is also a need to integrate ecology, to illuminate how early angiosperms established a roothold in pre-existing Mesozoic plant communities. These events were critical in guiding subsequent waves of angiosperm diversification during the Aptian–Albian. Phylogenetic studies identify Amborella, Nymphaeales (water lilies), Austrobaileyales, and Chloranthaceae as extant lineages that branched before the radiation of core angiosperms. Among living plants, these lineages may represent the best models for the ecology and physiology of early angiosperms. By combining phylogenetic reconstruction with new data on the morphology and ecophysiology of extant basal lineages, it appears that early angiosperms diversified shady, disturbed, and wet habitats. This ecology is supported low and easily light-saturated photosynthetic rates, leaf anatomy related to the capture of understory light, small seed size, and clonal reproduction. In this talk, I synthesize the current understanding of early angiosperm ecology, focusing on patterns of functional ecology, by merging recent molecular phylogenetic studies and functional studies on extant 'basal angiosperms' with the picture of early angiosperm evolution drawn by the fossil record. Broadly, ecological inferences from living plants appear consistent with anatomy and paleoecology of Early Cretaceous angiosperm fossils, which suggests extant basal angiosperms may be faithful analogs (or homologs) of early angiosperm biology. I discuss some examples of "functional stasis" and how inferences from inferences based on living plants can be tested with further study of the anatomy, chemistry, and sedimentological context of Early Cretaceous angiosperm fossils.
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1 - University of Tennesee, Knoxville, Ecology and Evolutionary Biology, Knoxville, Tennesee, 37996-1610, USA
Presentation Type: Symposium or Colloquium Presentation
Location: 134/Performing Arts Center
Date: Tuesday, August 1st, 2006
Time: 3:15 PM