The phylum Cnidaria is one of the earliest evolving animal groups and includes prominent members of the marine fauna such as corals, sea anemones and jellyfish. Because cnidarians diverged from the rest of the animals prior to the evolution of organs, their overall anatomy is quite simple. Despite this however, cnidarians have attained incredible diversity, comprising over 11,000 species, many of which display elaborate structures and complex life histories. The lack of organs and other anatomical landmarks has made it difficult for scientists to discern their evolutionary relationships. Recent technological and theoretical advances in the sequencing and analysis of DNA provide the opportunity to use the information encoded within an organism's genetic code to elucidate evolutionary relationships. The primary aim of this proposal is to obtain DNA sequence data from 1,800 cnidarian species: this will generate approximately 23 million base pairs of cnidarian DNA sequence, and the specimens from which the sequences are obtained will be retained in natural history museum collections. The information encoded in the DNA will be used to reconstruct cnidarian phylogenies (evolutionary trees), using computer algorithms and supercomputing facilities. Some of the questions this proposal will address are: Was the ancestor to all of cnidarians solitary or colonial? Are jellyfish or hydras more closely related to the corals? How and when did coral skeletons evolve? What are the evolutionary transitions between a simple hydra polyp and a complex Portuguese Man-of-War colony? Reconstructing a cnidarian evolutionary tree is important for our understanding of the patterns and processes that accompanied the early diversification of animal life.
Formal and informal education will result from this research. Undergraduate, graduate, and postdoctoral scholars, including those belonging to groups under-represented in the sciences, will be trained. A symposium on cnidarian evolutionary relationships will be organized by the investigators at a national scientific meeting. A Cnidaria Tree of Life database will be developed to include outreach and learning components such as images, common names, and keys designed to appeal to students at all levels as well as interested users such as divers and aquarists. Museum exhibits will be created based on research results, one at the University of Kansas Natural History Museum, and one, entitled "Cnidarian Diversity in the Oceans" that will be part of the new Oceans Hall, due to open at the National Museum of Natural History in 2008. A website and classroom poster (in both English and Spanish) integrated with the latter exhibit will be created in collaboration with a K-12 educator supported through NSF's Research Experience for Teachers program.
This project focused on investigating the biodiversity and relationships of a large group of early diverging marine invertebrates, the phylum Cnidaria. This research represented a collaborative effort by several principle investigators and included involvement of an entire community of researchers. From our investigations we now have a much better understanding of patterns of diversification in cnidarians. Some of the patterns uncovered were multiple invasions from shallow water to deep and vice versa, broad biogeographic distributions of deep water species, cryptic diversification of shallow water species, and complex patterns of life cycle evolution, including multiple losses of the pelagic medusa stage in the cnidarian group Hydrozoa. Members of our projects have collected specimens from all over the world, including the United States, South Africa, Chile, Japan, Panama, Moorea, Singapore, the Mid-Atlantic, Australia and Philippines. These collaborative field projects forged strong partnerships with local researchers. We have collected approximately 3,200 specimens from by various methods and at all ranges of depths. All of these specimens have been deposited into natural history museums and are available to the scientific community for future study. We have generated DNA sequence data from over 1100 specimens and sampled over 70% of cnidarian families. These DNA sequences have helped us to develop a robust and stable phylogenetic framework through which we can interpret the diversification patterns of this ancient lineage. Because Cnidaria is such a pivotal group for understanding the early diversification of animals, the phylogenetic trees generated are most powerful as we investigate them in light of other kinds of data, so that we may better understand the origin of symmetry, organs, tissues, immune systems, nervous systems, and the genetic mechanisms that drive these features. Sources of evidence we investigated with our improved phylogenetic perspective are fossils, gene expression, anatomy and the ultrastructure of the stinging structures, call nematocysts. Through the course of this project we published over 70 papers and trained 3 postdocs, 20 graduate students and over 40 undergraduates. We have built a searchable database for specimens and related data that is accessible to the public. We have given presentations on cnidarians to K-12 classrooms and at museum exhibits and incorporated our findings into classroom curriculum. The training of the next generation of cnidarian systematists, the building of museum collections, and generations of DNA sequence data will continue to contribute to the scientific progress on cnidarian diversity well after the completion of this official project.
