Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
The wisdom of the crowd: a crowd-sourcing task for character discovery from nematocyst ultrastructure Marymegan Daly , Abigail Reft , Edith Law , Maureen O’Leary 1 1,2 3 4 1 Dept. Evolution, Ecology & Organismal Biology, The Ohio State University; 2 Centre for Organismal Studies, Heidelberg, Germany; 3 Center for Research on Computation & Society, Harvard University; 4 Department of Anatomical Sciences, Stony Brook University School of Medicine Non-scientists are drawn to the aesthetic beauty of organisms and curious about the evolution of form. Focal problem: Nematocyst ultrastructure How can we use the eyes and brains of students and natural history enthusiasts to expand our ability to reconstruct and interpret the tree of life? Nematocysts are microscopic structures produced uniquely by members of Phylum Cnidaria (corals, sea anemones, jellyfish, and their kin). These micro-machines are used by corals, jellyfish, Hydra, and other cnidarians to capture prey, digest food, deter predators, and engage in intraspecific competition. Speeding the discovery and collection of morphological characters for phylogenetics Although DNA is now the primary means of building phylogenetic trees, morphological attributes remain critical to phylogenetics: morphological characters are often the focus of explanations or interpretations of trees built with molecular data, and are integral to the generation of tress that include species known only from e.g., fossils or formalin-fixed museum material. Although we have centuries’ worth of information about anatomy and histology, the morphological data set for any lineage tends to be replete with missing data: not all characters have been assessed for all organisms in all lineages. Furthermore, modern techniques like electron microscopy have not been applied to questions of morphology in many groups, in part because these techniques became widespread at the same time that phylogenetics underwent a shift away from morphology and towards DNA as the primary means of assessing relationships. Generating, extending, and completing morphological matrices is critical to reconstructing and understanding the tree of life. However, because these data require organismal and technical expertise and tend to be time-intensive to collect, their completeness and quality represent a major impediment to the reconstruction of a detailed and comprehensive tree of life. Through the “Assemble, Visualize, and Analyze the Tree of Life” grant fromprogram of the US National Science Foundation, we have developed interactive, web-based tools for discovering and scoring phylogenetic characters from high-quality images. These tools help to increase the speed and scale at which morphological data can be collected and thus help to make morphological data and tree reconstruction collection more efficient and effective. Curio: A platform for crowd sourcing character assessment Curio (Law et al., 2013) is a citizen-science platform that harnesses the curiosity of laypeople. Participants collect, annotate, and analyze e.g., images, audio, video, text, time series, or spatial data to test hypotheses developed by content experts. Because content experts need not have technical expertise in programming or experience with crowd-sourcing to use Curio, new crowd-sourcing projects can be launched with minimal effort. We are implementing Curio to develop new phylogenetic characters for nematocysts. Morphological matrices have been made using attributes visible with light microscopy but this set of features is not representative of the diversity of nematocysts, as electron microscopy (EM) reveals attributes not visible with light microscopy and light microscopy fails to differentiate structures distinguishable with EM. The participant is introduced to the broader question in an easy-to-understand context. Images loaded for the project can be used in multiple tasks and in multiple comparisons. “What characteristics distinguish nematocysts of sea anemones?” ~ Professor Meg Daly How do sea anemones manage to subdue and kill prey that moves when they themselves are stuck to the substrate? The answer comes from within! Like all cnidarians, sea anemones make microscopic killing machines called nematocysts.These are each smaller than a single cell, and are the most complex structure micrograph of an un-discharged nematocyst. Only the tubule is visible in the light micrograph. Electron microscopy of nematocysts reveals structural diversity unseen with light microscopy: the apex of the capsule varies from operculate, to cap-like, to tri-flapped, and spines or tubules indistinguishable under light microscopy can vary in shape and texture. The diversity of form has largely been explored in a functional context, or remarked upon anecdotally in studies of natural history, physiology, or taxonomic diversity. manufactured by any animal cell. Each nematocyst consists of a long tubule wound up and packed inside a tiny capsule; when the tubule erupts from the capsule, the spines and barbs on it sick into the skin or wrap around the body of the victim. Nematocysts show a lot of variation in their size, shape, and function. Many of the attributes of nematocysts visible under the 10,000 plus magnification of electron microscopy have not been described thoroughly for Three nematocysts differing in the morphology of the tubule: note differences in spine shape, spine arramgement, and tubule texture. most species of sea anemone. We aim to use the attributes of the nematocyst capsule, tubule, and spines to differentiate nematocysts from different species of sea anemone and to understand the ways in which these highly complex, minute machines have changed over evolutionary time. Meg Daly is an associate professor of Evolution, Ecology, and Organismal Biology at Ohio State University. We will develop new characters through an image comparison and annotation task, in which participants are given two images asked to draw an outline around the same part (e.g., “tubule,” “spine”, or “apex”) in each image and then describe, in plain language, the most salient differences between the two examples of this part. The Curio Interface for this project presents images of nematocysts from two species and asks the participant to differentiate them using non-technical language. In an undischarged nematocyst, a spined tubule lies coiled inside the capsule with which it is continuous. Upon stimulation, the tubule everts, turning inside-out and revealing spines and harpoons that penetrate the target. A diagrammatic discharged nematocyst and a light Annotation is especially helpful because the micrographs can contain multiple nematocysts and orientation varies from micrograph to micrograph. The plain language descriptions are helpful for the extension of crowdsourcing tasks because they provide non-technical descriptions that can be used to guide participants. Our goal is to document this diversity and understand how it has changed through evolution. Before we can reconstruct phylogenies or interpret the evolution of nematocysts, we must: 1) Atomize the diversity of form into phylogenetic characters. This is necessary to build trees of these attributes or to optimize the attributes onto trees constructed using other data. 2) Assess the diversity of form across a meaningful sample of taxa. Knowing a little bit about the attributes of few or incomparable sets of species is insufficient to resolve the evolution of these complex structures. References and Acknowledgements Edith Law, Conner Dalton, Nick Merrill, Albert Young, Krzysztof Z. Gajos. Curio: A Platform for Supporting Mixed-Expertise Crowdsourcing. HCOMP 2013. This project was supported by NSF DEB-1208523