应数学与统计学院邀请，芬兰赫尔辛基大学（University of Helsinki）数学与统计系教授Stefan A.H. Geritz将于6月8日—6月12日来我校进行学术交流并作学术报告。

        报告（一）
        题 目： The effect of noise and delays on the behavior of a population, and the need to be specific about the underlying mechanisms.
        时 间：2015年6月9日（周二），上午9：00～11：00
        地 点：理科楼202
        摘 要： A population is an ensemble of interacting individuals, and population behavior ultimately is the consequence of the behavior of these individuals. A population model therefore can be derived from a model of the behavior of the individuals. Following this procedure, different models for the individuals sometimes can lead to the very same model for the population, in which case it seems that the underlying behavior of the individuals may not be that important after all.
However, I show by means of examples that if additional processes such as environmental noise or developmental delays are incorporated into to the model, then they can affect the population behavior in different ways depending on the underlying model for the individuals. This is why modifications of a population model should preferably be made on the level of the individuals rather than directly on the population model itself.

        报告（二）
        题 目：Adaptive correlations: co-evolution of seed size and germination time as an example.
        时 间：2015年6月10日（周三），上午9：00～11：00
        地 点：理科楼202
        摘 要： In this paper we present a model for the co-evolution of seed size and germination time when both affect the ability of the seedlings to compete for space. We show that even in the absence of a morphological or physiological trade-off between the two traits, a strong correlation between seed size and germination time is likely to evolve, which raises the more general question to what extent a trade-off between any two traits should be considered as an a priori constraint or as an evolved means to actually implement a beneficial correlation between the two traits. We relate the sign of the evolved correlation between seed size and germination time to seed and seedling survival and seedling growth.

        报告人简介：Stefan A.H. Geritz是芬兰赫尔辛基大学（University of Helsinki）数学与统计系教授。主要研究领域是生物数学，特别是适应动力学理论及其在生态系统和传染病中的应用。Stefan A.H. Geritz教授是适应动力学理论的共同创始人之一，发表了40多篇论文，总的引用次数为2295次，H-指数为18，其中他们发表的2篇论文 (Metz et al. 1992; Geritz et al. 1998) 目前已被引用564次和722次。目前是“Theory in Biosciences”等国际杂志的编委。
         

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