PATTERN AND PROCESS IN PALEOBIOLOGY - THE ROLE OF CLADISTIC-ANALYSIS IN SYSTEMATIC PALEONTOLOGY
PATTERN AND PROCESS IN PALEOBIOLOGY - THE ROLE OF CLADISTIC-ANALYSIS IN SYSTEMATIC PALEONTOLOGY
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DOI：
10.1017/s0094837300025513
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发表时间：
1981-01-01
期刊：
影响因子：
2.7
通讯作者：
CRACRAFT, J
中科院分区：
文献类型：
--
作者：
CRACRAFT, J
系统分类学和古生物学在概念上有着悠久的关系，它们被重建生命历史的共同目标所结合。然而，除了少数例外，古生物学家几乎没有投入系统的理论和方法。其原因显然与后达尔文古生物学的两个概念哲学传统有关：一是广泛采用的物种概念，其中分类群被视为进化连续体的非离散的、任意指定的片段;二是相信系统发育重建主要是通过地层记录追踪进化变化的经验问题。现有的系统证据支持这样一种假设，即物种是时空中真实的离散单位，除非它们被假定为另一个物种的直接祖先，否则它们可以通过拥有一个或多个进化上的新奇特征（衍生特征）来定义。物种的起源是由物种形成（替代）事件和随后的物种形成事件或终止。自然类群是由具有共同谱系历史的分类群组成的。支序分析是一种构建和检验单系假说并由此确定自然类群的方法。分支系统假说是研究当代古生物学中许多主要问题所必需的。事实上，如果不参考关于自然类群组成的分支系统学假说，就不可能对进化速率、分类多样性模式、分类进化模式和形态多样化模式进行研究。由于古生物学的内容是历史的，古生物学家在使用古生物学数据来研究进化过程问题的能力方面受到很大限制。根据目前的进化理论，适应和自然选择的概念与当地种群内发生的遗传和生态过程（微进化）有关。如果是这样的话，那么与研究这些现象相关的数据很可能在古生物样本中缺乏。古生物学模式的阐述，包括过程相关的概念，如适应和自然选择是公理在其逻辑结构，因此不能被证伪或批判性地评估的古生物学模式。
Systematics and paleontology have had a long conceptual relationship, united by the common goal of reconstructing the history of life. Yet, with few exceptions, paleontologists have had little input into formulating systematic theory and methodology. The reasons for this apparently relate to 2 conceptual-philosophical traditions of post-Darwinian paleontology: the widespread adoption of a species concept in which taxa are viewed as nondiscrete, arbitrarily designated segments of evolutionary continua, and the belief that phylogenetic reconstruction is primarily an empirical matter of tracing evolutionary change through the stratigraphic record. Available systematic evidence supports the hypothesis that species are real, discrete units in space and time and that, unless they are postulated to be directly ancestral to another species, they can be defined by the possession of one or more evolutionary novelties (derived characters). Species beginnings are delineated by speciation (vicariance) events and their terminations by subsequent speciation events or by extinctions. Natural groups are composed of taxa that have shared a common genealogical history. Cladistic analysis is a method to construct and test hypotheses of monophyly and thereby define natural groups. Cladistic hypotheses are necessary to investigate many of the major questions within contemporary paleobiology. Virtually no studies of evolutionary rates, patterns of taxonomic diversity, modes of taxic evolution and patterns of morphological diversification can be undertaken without reference to cladistic hypotheses about the composition of natural groups. Because paleobiology is historical in its content, paleontologists are greatly limited in their ability to use paleontological data to investigate questions about the evolutionary process. According to current evolutionary theory, the concepts of adaptation and natural selection relate to genetic and ecological processes that take place within local populations (microevolution). If so, then data relevant to examining these phenomena are likely to be lacking in paleontological samples. Explanations of paleontological patterns that include process-related concepts such as adaptation and natural selection are axiomatic in their logical structure and thus cannot be falsified or critically evaluated by that paleontological pattern.