Jaeckle, Faculty Advisor, William

Kozak, Ellen

Steffen, Rhiannon

Tarbutton, Morgan

Wessel, Jeff

Digital Commons @ Illinois Wesleyan University

Illinois Wesleyan UniversityDigital Commons @ IWUJohn Wesley Powell Student ResearchConference 2008, 19th Annual JWP ConferenceApr 12th, 9:00 AM - 10:00 AMWhat is Influencing Juvenile Volume and Weight?Ellen KozakIllinois Wesleyan UniversityRhiannon SteffenIllinois Wesleyan UniversityMorgan TarbuttonIllinois Wesleyan UniversityJeff WesselIllinois Wesleyan UniversityWilliam Jaeckle, Faculty AdvisorIllinois Wesleyan UniversityFollow this and additional works at: http://digitalcommons.iwu.edu/jwprcThis Event is brought to you for free and open access by The Ames Library, the Andrew W. Mellon Center for Curricular and FacultyDevelopment, the Office of the Provost and the Office of the President. It has been accepted for inclusion in Digital Commons @ IWU bythe faculty at Illinois Wesleyan University. For more information, please contact digitalcommons@iwu.edu.©Copyright is owned by the author of this document.Ellen Kozak; Rhiannon Steffen; Morgan Tarbutton; Jeff Wessel; and William Jaeckle, Faculty Advisor, "What isInfluencing Juvenile Volume and Weight?" (April 12, 2008). John Wesley Powell Student Research Conference. Paper 13.http://digitalcommons.iwu.edu/jwprc/2008/posters/13THE JOHN WESLEY POWELL STUDENT RESEARCH CONFERENCE - APRIL 2008 Poster Presentation P25 WHAT IS INFLUENCING JUVENILE VOLUME AND WEIGHT? Ellen Kozak. Rhiannon Steffen. Morgan Tarbutton. Jeff Wessel and William Jaeckle* Biology Department, Illinois Wesleyan University Intuition predicts the more nutrients available during development, the larger the offspring. Larger amounts of ingested nutrients should increase juvenile size above that if lesser amounts of nutrients were consumed. The freshwater snail, Physa sp., is hermaphroditic and lays its encapsulated eggs in a mass of jelly-like material. The capsular fluid contains all of the available nutrients for the developing snail. We tested the hypothesis that a larger capsule would produce a larger juvenile because more nutrients are available to the developing embryo. Egg masses were collected and individual egg capsules were placed into separate wells for developmental observation. Length and width of each capsule and hatched juvenile were measured. After hatching the juveniles were frozen and then dried to a constant weight. Surprisingly, we found no relation between capsule volume and juvenile size. Instead, there was an inverse relation between capsule volume and juvenile volume per capsule volume. In essence, the relationship indicated that the proportion of capsular volume represented in juvenile size decreases with increasing capsule size. Two possible explanatory hypotheses are that snail embryos are metabolically inefficient, or that capsular size does not reflect available nutrients. 

What is Influencing Juvenile Volume and Weight?

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What is Influencing Juvenile Volume and Weight?

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