The Evolutionary Dynamics of a Dormant Egg Pool

许多生物的休眠生活史阶段，包括大多数陆地植物、许多陆地和淡水无脊椎动物，甚至少数脊椎动物，代表着物种和遗传多样性的储存。当环境随着时间的推移发生变化时，这些抗性阶段(通常是种子和卵)会阻止那些无法承受活动状态变化的生物灭绝。这项研究探索了一系列问题，即在不断变化的环境中，休眠阶段如何影响变异的生存和保持。这项工作结合了新的数学理论的发展，并使用了一种居住在湖泊的甲壳类桡足类动物(长约1毫米)作为模型系统。这是一个已经知道了相当多信息的国家。将讨论四个主要问题：(1)长期休眠的环境和生理基础是什么；(2)与长期休眠相结合的时间波动环境是否提供了一种保持比其他情况下更大变化的机制；(3)泥沙过程(休眠阶段的混合、沉淀、死亡)如何影响可变阶段的分布；以及(4)是否可以通过对休眠阶段的储存的理解来解释已经对所讨论的桡足类种群进行的观察？这项研究包括对湖泊沉积物进行现场采样，在实验室饲养桡足类动物，以及将数学理论与已知过程仔细匹配。理论将在其在桡足类系统中的应用建立后得到推广。目前的预测是，美国东北部的气候将变得更加干燥，而且变得更加多变。了解处于休眠阶段的物种可能如何应对这些变化，将有助于指导对动植物丰度和分布变化的预测。

The dormant life-history stages of many organisms, including most terrestrial plants, many terrestrial and freshwater invertebrate animals, and even a few vertebrates, represent a storage of species and genetic diversity. When environments change through time, these resistent stages (typically though not always seeds and eggs) prevent extinction of those types of organisms that could not withstand the change in their active states. This research explores a series of questions about how dormant stages affect survival and maintenance of variation in the presence of a changing environment. The work combines development of new mathematical theory with the use of a species of lake-inhabiting crustacean copepods (ca. 1 mm long) as a model system. It is one for which considerable information is already known. Four major questions will be addressed: (1) What is the environmental and physiological basis for the long-term dormancy, (2) Does a temporally-fluctuating environment combined with long- term dormancy provide a mechanism for maintaining greater variation than would otherwise occur, (3) How do sediment processes (mixing, settling, mortality of dormant stages) affect the distribution of variable stages, and (4) Can observations already made on the copepod population in question be explained through an understanding of storage of dormant stages? The research involves a combination of field sampling of lake sediments, rearing of copepods in the laboratory, and a careful matching of mathematical theory with known processes. Theory will be generalized after its application to the copepod system is established. Current predictions are for climates to become both drier in the northeastern US and to become more variable. Understanding how species with dormant stages are likely to respond to these changes will help guide predictions of changes in plant and animal abundance and distribution.