The evolution of life histories in geminate echinoderms: a comparative approach to unscrambling the relationships among environment, egg size, and the energetics of development.

卵的大小是海洋生物生活史中最重要和经常研究的方面之一，并且与许多性状相关，包括幼虫发育模式、幼虫发育长度、饥饿抗性、幼虫形态和功能、变态时的大小以及幼鱼的生长和存活。很多注意力都集中在生态因素，驱动进化变化的鸡蛋大小，但生态，进化和生理方面的幼虫发育之间的关系还没有得到表征。同样，虽然关于卵的大小和发育中的幼虫利用卵能量之间的关系的假设是建立在海洋生物生命史进化的所有主要模型中的，但没有研究明确地在严格的比较框架中测试这些模型的基本假设，并充分描述了生态和进化背景。 为了研究这些假设，主要研究人员将使用成对的棘皮动物的双生物种对分离的中美洲航道关闭作为模型系统，了解鸡蛋大小的演变及其对海洋无脊椎动物之间的广泛的其他生活史相关的影响。 研究要解决的具体问题包括：（1）与鸡蛋大小进化变化相关的生化成分变化是什么？ (2)卵大小、卵成分和卵总能量的进化差异如何影响幼虫的生长速率和发育轨迹？(3)在营养型物种中，较大的卵是否比较小的卵贡献了更高比例的能量？(4)卵的大小如何影响随后的幼虫表现在不同的食物制度，模仿对比自然食物环境中的两个海洋？更广泛的影响包括资助一名博士后研究员，两名研究生和至少3名本科生。学生将直接参与在巴拿马收集的样本的工作，并将学习比较生物学，数据采集和组织的原则，并通过直接（在教师的监督下）与他们自己收集的数据集工作的数据分析。这项研究将通过克莱姆森大学主办的网页向公众传播，并由主要研究者维护，并将作为开发“幼虫维基”的基础，这是一个公共网络资源，可以由任何人贡献和编辑。 主要研究人员希望这个维基将成为一个自我维持的资源，将是相当大的使用幼虫生物学家的全球社区作为一个论坛，讨论重大问题，传播信息，并分享教学和公开演示的照片。

Egg size is one of the most important and often-studied aspects of the life history of marine organisms, and is correlated with many traits including larval developmental mode, length of larval development, starvation resistance, larval form and function, size at metamorphosis, and juvenile growth and survival. Much attention has focused on the ecological factors that drive evolutionary changes in egg size, but the relationships between ecological, evolutionary, and physiological aspects of larval development have yet to be characterized. Likewise, while assumptions about the relationships between egg size and the utilization of egg energy by developing larvae are built into all major models of life history evolution in marine organisms, no study has explicitly tested the underlying assumptions of these models in a rigorous comparative framework with a well-described ecological and evolutionary context. To examine these assumptions, the principle investigator will use geminate species pairs of echinoderms separated by the closure of the Central American Seaway as a model system for understanding the evolution of egg size and its implications for a wide range of other life history correlates among marine invertebrates. Specific questions to address by the research include: (1) What are the changes in biochemical composition that are associated with evolutionary changes in egg size? (2) How do evolved differences in egg size, egg composition, and total egg energy affect the growth rates and developmental trajectories of larvae? (3) In planktotrophic species, do larger eggs contribute a higher proportion of energy to the total cost of development than smaller eggs? (4) How does egg size affect subsequent larval performance under different food regimes that mimic the contrasting natural food environments in the two oceans? The broader impacts include funding one postdoctoral researcher, two graduate students, and at least 3 undergraduates. Students will be directly involved working with samples collected in Panama, and will learn the principles of comparative biology, data acquisition and organization, and data analysis by working directly (under faculty supervision) with datasets they collect themselves. This research will be communicated to the public via a web page hosted at Clemson University and maintained by the principle investigator and will serve as the foundation for the development of a "Larval Wiki," a public web resource that can be contributed to and edited by anyone. The principle investigator hopes this Wiki will become a self-sustaining resource that will be of considerable use to the global community of larval biologists as a forum for discussing major issues, disseminating information, and sharing photographs for teaching and public presentations.