COLLABORATIVE RESEARCH: Graptolite Macroevolution: Phylogenetic Analysis and Testing Hypotheses of Directional Change

“合作研究。笔石的宏观进化：系统发生分析和方向性变化假说的检验。米切尔和丹尼尔高曼。进化论中最有争议的问题之一是进步的概念。一些科学家主张对主要群体的进化有一个有条件的预期，而另一些科学家则认为我们应该预期进化历史主要是非进步的。量化进化模式的努力产生了相互矛盾的结果。因此，自然选择是否会导致长期进步趋势的问题仍然存在争议和令人沮丧。这项研究的中心目标是确定一组名为笔石的化石中是否存在显著的进步进化趋势。笔石是一组灭绝的海洋生物，大约在5.05亿至3.1亿年前繁荣。笔石化石记录提供了一个极好的机会，可以对定向进化进行严格的检验，原因有二。首先，笔石演化模式长期以来一直被用作渐进演化的教科书范例。第二，笔石的化石记录非常好，其时间和地理分布已被深入研究。 这里提出的工作，预计将大大有助于增加对笔石演化机制及其下降途径的理解。它也有望导致古生物学家研究进化模式和过程的方法的改进。人们认为，这两种结果都可能对测试化石记录以寻找进化进步的证据以及进化可能发生的方式这一更广泛的问题产生积极影响。

"Collaborative Research. Graptolite Macroevolution: Phylogenetic Analysisand Testing Hypotheses of Directional Change".Charles E. Mitchell and Daniel Goldman. One of the most contentious issues in evolutionary theory is the notion of progress. Some scientists have argued for a qualified expectation of progress in the evolution of major groups while others have argued that we should expect evolutionary histories that are dominantly non-progressive. Efforts to quantify evolutionary patterns have produced conflicting results. Thus, the question of whether natural selection leads to long-term progressive trends remains controversial and frustrating. The central goal of the proposed research is to determine if there were significant progressive evolutionary trends within a group of fossils called graptolites. Graptolites are a group of extinct marine organisms that flourished from approximately 505 to 310 million years ago. The graptolite fossil record offers an outstanding opportunity to make a rigorous test of directional evolution for two reasons. First, graptolite evolutionary patterns have long been used as textbook examples of progressive evolution. Secondly, the fossil record of graptolites is exceptionally good, and their temporal and biogeographic distributions have been intensively studied. The work proposed here is expected to contribute substantially to an increased understanding of the mechanisms of graptolite evolution and their pathways of descent. It is also expected that it will lead to improvements in the methods paleobiologists employ to study evolutionary pattern and process. Both of these outcomes are likely, it is thought, to positively effect the broader issue of testing the fossil record for evidence of progress in evolution and the means by which it might occur.