Parsimony Trees, Best-Fit Fences, and Consensus Sequences: Integrating Cladistics and Biostratigraphy at High Resolution

9980372萨德勒树形图总结了物种或更高分类群之间的进化关系。 在树枝的顶端有物种标签，树的其余部分描绘了祖先。 计算机算法很大程度上是为了树中的分支模式，这最简单地解释了物种之间大量的形态和生化比较。 相似性可能是从一个共同的祖先遗传而来的，或者它们可能代表了不太密切相关的类群之间的外观趋同--这使搜索变得复杂。不同地点地层之间的时间相关性用栅栏状图表示。 每一个地方的地层序列都画在自己的栅栏柱上，“电线”将同一时代的地层从一个地方连接到另一个地方。 许多电线代表化石分类群的起源时间。由于化石的保存和收集不完善，各地在起源顺序的细节上往往相互矛盾。 计算机算法寻找最能解决这些矛盾的栅栏。对最好的栅栏和树的搜索通常会找到不止一个同样好的解决方案。 搜索使用不同的证据，但树木和围栏都包括关于形态特征出现顺序的推断。 本项目将设法将这两种搜索程序联合收割机结合起来，使每一种程序都能帮助减少另一种程序找到的同样好的解决办法的范围。

9980372SadlerTree-shaped diagrams summarize evolutionary relationships between species or higher taxa. With species labels at the tips of branches, the rest of the tree depicts ancestry. Computer algorithms much for a branching pattern in the tree that most simply explains a large array of morphological and biochemical comparisons between the species. Similarities may be inherited from a common ancestor, or they may represent convergence of appearance between less closely related taxa - this complicates the search.Time correlations between strata at different localities are represented by fence-like diagrams. With the sequence of strata at each locality drawn on its own fence post, "wire lines' connect horizons of the same age from locality to locality. Many of the wire lines represent the time of origination of a fossil taxon. Because of imperfect preservation and collection of fossils, the localities tend to contradict one another in detail concerning the order of originations. Computer algorithms search for the fence that best resolves these contradictions.Searches for the best fences and trees typically find more than one equally good solution. The searches use different evidence; but trees and fences both include inferences about the order of appearance of morphological traits. This project will develop ways to combine the two search procedures so that each can help reduce the range of equally good solutions found by the other.