The Role of Phenotypic Plasticity in the Interpretation of Stratophenetic Patterns in the Paleozoic

表型可塑性在古生代平流层模式解释中的作用

• 批准号: 0844143
• 负责人: Brenda Hunda
• 金额: $ 10万
• 依托单位: Cincinnati Museum Center
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0844143&HistoricalAwards=false
• 关键词: Role; Phenotypic; Plasticity; Interpretation; Stratophenetic

The Role of Phenotypic Plasticity in the Interpretation of Stratophenetic Patterns in the PaleozoicBrenda R. Hanke and Andrew J. WebberMany evolutionary studies focus on how populations of organisms adapt and change in the face of environmental changes. The raw material upon which natural selection acts is plasticity, or variability, in an organism?s phenotypes (the physical expression, such as body size, shape, and others, of the genetic make-up of an organism). Nearly all phenotypes will show some plasticity because traits that are expressed result from the interaction of genetics with environment. The relationship between the plasticity of phenotypes and variable environmental conditions, however, still requires further understanding. While numerous biological studies have addressed this relationship with modern organisms, even extending into the young fossil record, this area of research has been lacking in settings that are much older. The power of the fossil record is that it allows us to measure changes within a species over longer time scales; but can paleontology?s contribution to evolutionary biology improve our understanding of the relationship between phenotype and environment over time? There are two primary steps in achieving this goal: 1. the geographic distribution of phenotypic variability within a species and how it corresponds to spatial environmental gradients (known as a reaction norm) must be accurately documented. 2. The reaction norm for a species must then be evaluated over time.The goal of this research is to describe the relationship between paleoenvironmental conditions and variability in the shape of two trilobite species within rocks of the Kope Formation (Ordovician Period, around 450 million years old). In this study, morphology is measured using geometric morphometrics, which quantifies shape change at high resolution. Paleoenvironmental change is measured through gradient analysis, which uses the distribution and abundance of fossil remains to characterize environment. Preliminary research shows a statistically significant portion of shape variability in the cranidium (head) of the trilobite Flexicalymene granulosa is related to the environment in which this species is preserved. This relationship between shape and environment lead us to propose that patterns of change through time in this trilobite species is the result of populations following their preferred environments (also known as environmental tracking). To test our hypothesis, the next step is to systematically track this established relationship through time. To this end, we will compare cranidial shape to general geological interpretations, such as rock type, of environment, and to a quantified measure of environment acquired through gradient analysis in the Kope Formation. Intensive field work conducted over the next three years will provide a comprehensive dataset of trilobite cranidial shape and environment through time and space from which to test our hypothesis.This study has direct implications for understanding how variation within a trilobite species contributes to evolution within trilobites as a group. It compares morphological change to a high-resolution measure of environmental change using a novel approach, which can be used on many organisms in many geological settings. An important component of this study will be the integration of scientific research with science education through a workshop developed at Cincinnati Museum Center designed to provide training for regional science teachers in geology and paleontology.

表型可塑性在解释古生代地层表型模式中的作用。汉克和安德鲁J韦伯许多进化研究的重点是生物种群如何适应和改变面对环境的变化。自然选择作用的原材料是有机体的可塑性或变异性？表型（生物体遗传组成的物理表现，如身体大小、形状等）。几乎所有的表型都会表现出一定的可塑性，因为所表达的性状是遗传与环境相互作用的结果。然而，表型的可塑性和可变的环境条件之间的关系，仍然需要进一步的理解。虽然许多生物学研究已经解决了与现代生物的这种关系，甚至延伸到年轻的化石记录，但这一领域的研究一直缺乏更古老的环境。化石记录的力量在于它使我们能够在更长的时间尺度上测量一个物种的变化;但古生物学可以吗？他对进化生物学的贡献提高了我们对表型和环境之间关系的理解？实现这一目标有两个主要步骤：1。必须准确记录物种内表型变异的地理分布及其如何对应于空间环境梯度（称为反应标准）。2.一个物种的反应规范，然后必须随着时间的推移进行评估。本研究的目标是描述古环境条件和变化之间的关系在科佩组（奥陶纪时期，约4.5亿年）的岩石中的两个三叶虫物种的形状。在这项研究中，形态测量使用几何形态测量学，它量化的形状变化在高分辨率。古环境变化是通过梯度分析来衡量的，梯度分析利用化石遗迹的分布和丰度来表征环境。初步研究表明，在三叶虫Flexicalymene granulosa的颅（头）的形状变异的统计学显着的一部分是与该物种保存的环境。形状和环境之间的这种关系使我们提出，随着时间的推移，这种三叶虫物种的变化模式是种群遵循其首选环境（也称为环境跟踪）的结果。为了验证我们的假设，下一步是系统地追踪这种建立起来的关系。为此，我们将比较颅骨形状一般地质解释，如岩石类型，环境，并通过梯度分析在科佩组获得的环境的量化措施。在接下来的三年里进行的密集的实地工作将提供一个全面的数据集，三叶虫颅的形状和环境，通过时间和空间来测试我们的hypothes.This研究有直接的影响，了解如何在一个三叶虫物种的变化有助于三叶虫作为一个群体内的进化。它使用一种新的方法将形态变化与环境变化的高分辨率测量进行比较，该方法可用于许多地质环境中的许多生物。这项研究的一个重要组成部分将是科学研究与科学教育的整合，通过在辛辛那提博物馆中心举办的一个讲习班，旨在为地质学和古生物学方面的区域科学教师提供培训。