CAREER: A COMPARATIVE STUDY OF EXTRINSIC AND INTRINSIC ISOLATION IN KILLIFISH - USING STUDIES OF SPECIATION TO DEVELOP RESOURCES FOR TEACHING SPECIATION

由于关系密切的物种往往在栖息地不同，生态差异在物种形成中可能很重要。生态物种形成的两种可能机制称为外在隔离和内在隔离。当中间形态的杂种不能找到合适的栖息地时，就会发生外源隔离。内在隔离发生在杂种的适应度降低时，而不考虑生境，也就是说，问题与杂种生理等内部因素有关。挑战在于确定哪一种隔离首先出现，以及它们对种群继续成为独特物种的相对贡献。对大多数动物来说，物种形成需要很长时间才能直接观察到，但有些动物可以在物种形成的过程中被捕捉到。这些物种是推断外在和内在隔离的顺序和程度的理想选择，因为种群可以在分化的不同阶段进行研究，从最近分化到完全不能杂交。该项目关注的是鳉鱼种群的生态物种形成，这是研究生态物种形成的理想选择，因为鳉鱼种群已经多次从淡水到咸水的梯度上分化。PI将测量淡水和咸水种群之间的外在和内在隔离，并将结果与在相似盐度中发现的种群进行比较。教师和生物教育专业的学生几乎都被纳入了所有拟议的活动；他们将进行研究并开发课程材料。PI的目标是通过参与研究提供对物种形成的透彻理解。每年将举行一次关于进化论教学的研讨会，以在教育者和科学家之间建立一个持续的讨论。最后，将举办一个夏季讲习班，向当地教师传授进化论知识，并传播通过该项目编制的课程材料。

Because closely related species often differ in habitat, ecological differences could be important in speciation. The two possible mechanisms of ecological speciation are called extrinsic and intrinsic isolation. Extrinsic isolation occurs when hybrids that are intermediate in form cannot find appropriate habitat. Intrinsic isolation occurs when hybrids have reduced fitness regardless of habitat, that is, the problem has to do with internal factors such as hybrid physiology. The challenge is to determine which kind of isolation arose first and their relative contributions to allowing populations to continue towards being distinct species. For most animals, speciation takes too long to observe directly, but some can be caught in the process of speciation. Such species are ideal for making inferences about the order and magnitude of extrinsic and intrinsic isolation because populations can be studied at various stages of divergence, from recently diverged to completely unable to hybridize. This project focuses on ecological speciation among populations of killifish, which are ideal for studying ecological speciation because populations have diverged across a gradient from freshwater to saltwater multiple times. The PI will measure extrinsic and intrinsic isolation between freshwater and saltwater populations and compare the results with those from populations that are found in similar salinities. Teachers and biology education majors are incorporated into nearly all the proposed activities; they will conduct research and develop curriculum materials. The goal of the PI is to provide a thorough understanding of speciation through participation in research. A yearly seminar event will be held on teaching evolution to create an ongoing discussion between educators and scientists. Finally, a summer workshop will be held to educate local teachers about evolution and disseminate the curriculum materials developed through this project.