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2009 Annual Science Report

Massachusetts Institute of Technology Reporting  |  JUL 2008 – AUG 2009

Paleontological Investigations of the Advent and Maintenance of Multicellular Life

Project Summary

We have focused research on functional physiological investigations of early land plants, products of an origin of complex multicellularity distinct from the events that gave rise to animals. We have been able to show show basic attributes of anatomy were modified to facilitate physiological adaptation of early land plants. We also completed a functional analysis of early multicelullar organisms that stresses the constaints imposed by diffusion and the means of circumventing them.

4 Institutions
3 Teams
6 Publications
1 Field Site
Field Sites

Project Progress

Origin of animals: We have been developing a new database of Ediacaran-Cambrian fossil occurrences for use in a study of the role of ecosystem engineering. Progress has also been made on quantitative models of this process (Krakauer et al. 2009) and in the role of hierarchical structuring of developmental regulatory systems (Erwin & Davidson 2009).

Early Land Plants: To investigate the hydraulic consequences of anatomical development in early land plants, we adapted a model of water transport in xylem cells that accounts for resistance to flow from the lumen, pits, and pit membranes, and that can be used to compare extinct and extant plants in a quantitative way. Application of this model to early vascular plants indicates that extinct seed plants evolved a structural and functional diversity of xylem architectures broader, in some ways, than the range observable in living seed plants.

Publications

  • Erwin, D. H. (2009). Climate as a Driver of Evolutionary Change. Current Biology, 19(14), R575–R583. doi:10.1016/j.cub.2009.05.047

  • Erwin, D. H. (2009). Early origin of the bilaterian developmental toolkit. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1527), 2253–2261. doi:10.1098/rstb.2009.0038

  • Erwin, D. H., & Davidson, E. H. (2009). The evolution of hierarchical gene regulatory networks. Nature Reviews Genetics, 10(2), 141–148. doi:10.1038/nrg2499

  • Krakauer, D. C., Page, K. M., & Erwin, D. H. (2009). Diversity, Dilemmas, and Monopolies of Niche Construction. The American Naturalist, 173(1), 26–40. doi:10.1086/593707

  • Sperling, E. A., Peterson, K. J., & Pisani, D. (2009). Phylogenetic-Signal Dissection of Nuclear Housekeeping Genes Supports the Paraphyly of Sponges and the Monophyly of Eumetazoa. Molecular Biology and Evolution, 26(10), 2261–2274. doi:10.1093/molbev/msp148

  • Sperling, E. A., Robinson, J. M., Pisani, D., & Peterson, K. J. (2010). Where’s the glass? Biomarkers, molecular clocks, and microRNAs suggest a 200-Myr missing Precambrian fossil record of siliceous sponge spicules. Geobiology, 8(1), 24–36. doi:10.1111/j.1472-4669.2009.00225.x