The Evolution of Life-History and Development in Echinoids: A Test for the Role of Environmental Factors and Macroevolutionary Correlates

9706579埃姆雷特--海洋无脊椎动物的历史和发展是紧密相连的--使许多小卵产生摄食幼虫的物种，以及那些产生很少(呃)、大(R)卵的物种产生远洋、非摄食或孵化的后代。这些特征被认为反映了生态和环境因素。尽管描述了许多现存分类群的生活史/发育模式，并在某种程度上与纬度和气候条件相对应，但这些模式的原因(或后果)尚不清楚。例如，几项关于腹足类软体动物化石的研究报告了生活史/发育与物种形成率和地理范围之间的相关性，但发育转变的原因仍然不清楚。本提案将调查一个化石记录良好的分支(纲：棘皮动物纲：棘皮动物门)，该分支在许多独立的谱系中进化为非浮游到营养(=非摄食的幼虫或孵化)。这项研究将考察在第三纪(最后65 Ma)发生不同生活史/发展模式的地点、时间和环境条件。这项建议的目的是：1)构建棘球藻类的形态和分子系统发育图，以确定非摄食发育以这种顺序进化的次数。2)考察生活史/发育模式是否影响海胆的物种形成率或地理范围。3)探索生活史/发育模式向少大卵和非浮游营养型发育转变的环境条件。一个由大约60+个字符组成的形态特征集将从大约30-40个活的和化石的属或亚属中收集。将参观澳大利亚、欧洲和印度的主要博物馆藏品，研究化石和最近的类型，并收集字符集。天牛科的系统发育分析将使用标准的数值分支，例如S软件程序PAUP将被用来构建最简约的树，这些树将随后被用于系统发育结构和稳健性的探索。在分子系统发育方面，我们将从约15个属和亚属中收集28S rRNA和线粒体细胞色素氧化酶I(COI)基因的部分序列，并将其与已建立的棘球类分子数据库整合。DNA将被提取并用PCR进行扩增，基因片段将在自动测序仪中进行测序。在序列比对之后，将使用简约(PAUP)和最大似然(PHYLIP)来构建系统发育树。使用全证据方法，形态和分子数据将结合在一起，以便使用上述方法估计该群体的最佳系统发育树。化石和最近分类群的发展数据将被绘制到树(S)上，以确定非浮游植物营养进化的次数和地点。研究海胆和其他已知系统发育的化石类群的发育模式，以确定生活史/发育模式是否会影响海胆的物种形成率或地理范围，就像一些腹足软体动物所显示的那样。最后，还将对生活史/发展模式转变的环境条件进行定量和统计检验。这项拟议的研究将是首次对具有良好化石记录的群体的生活史(和发育模式)的进化进行详细研究，该群体专门在真正严格的系统发育框架内建立。因此，这项研究将提供发育模式的时间和空间演化史，这些模式在很大程度上仍然是推测的，因为它们是基于最近分类群的模式或理论。这项研究还应该增进对全球变化如何推动棘球动物(以及L属的海洋无脊椎动物)发育模式发生重大变化的理解。这项工作还将为主要的棘球类动物建立一个安全的系统发育图，随后可以用来探索随着时间的推移而进一步进化的模式。

9706579 Emlet Life-history and development of marine invertebrates are closely linked - species that make many small eggs produce feeding larvae and those that make few(er), large(r) eggs produce either pelagic, nonfeeding or brooded offspring. These traits are thought to reflect ecological and environmental factors. Though life-history/developmental patterns are will described for many extant taxa and to some degree correspond to latitudinal and thus climatological conditions, the reasons for (or consequences of ) these patterns are poorly understood. For instance, several studies on fossil gastropod mollusks have reported correlations between life-history/development and speciation rates and geographical range, but reasons for shift in development remain obscure. The present proposal will investigate a clade (Class: Echinoidea, Phylum: Echinodermata) with a good fossil record which has evolved non-planktotrophy (=nonfeeding larvae or brooding) in many independent lineages. The study will examine where, when and under what environmental conditions different life-history/developmental patterns occurred in the Tertiary (last 65 Ma). The objectives of this proposal are to: 1) Construct morphological and molecular phylogenies for temnopleuroid echinoids in order to resolve the numbers of times that nonfeeding development has evolved in this order. 2) Examine whether life-history/developmental mode affects speciation rate or geographic range of sea urchins. 3) Explore the environmental conditions under which life-history/developmental modes shift to few large eggs and non-planktotrophic development. A morphological character set consisting of some 60+ characters will be collected from some 30-40 living and fossil genera or subgenera. Visits to major museums collections in Australia, Europe and India will be undertaken to study fossil and Recent types and to collect the character set. The phylogenetic analysis of the temnopleuroids will use standard numerical cladistics, e.g. the s oftware program PAUP will be used to construct maximally parsimonious trees that will be subsequently explored for phylogenetic structure and robustness. For the molecular phylogeny, partial sequences of 28S rRNA and mitochondrial cytochrome oxidase I (COI) genes will be collected from ~ 15 genera and subgenera of temnopleurid and integrated with a molecular database already constructed for echinoids. DNA will be extracted and amplified with PCR, and gene fragments will be sequenced in an automated sequencer. Following sequence alignment, phylogenetic trees will be constructed using both parsimony (PAUP) and maximum-likelihood (PHYLIP). Using a total evidence approach, morphological and molecular data will be combined in order to estimate the best phylogenetic tree for the group using the methodologies outlined above. Developmental data for fossil and Recent taxa will be mapped onto the tree(s) to determine the number of times and locations where non-planktotrophy evolved. The patterns of development among temnopleuroids and other fossil taxa with known phylogenies will be explored to determine whether or not life-history/developmental mode affects speciation rate or geographic range of sea urchins as has been shown for some gastropod molluscs. Finally the environmental conditions under which life-history/developmental modes shift will also be examined quantitatively and statistically. The proposed research will be the first detailed study of the evolution of life history (and developmental mode) for a group with a good fossil record specifically set within a truly rigorous phylogenetic framework. Consequently, this study will provide a temporal and spatial evolutionary history of developmental patterns that have remained largely speculative because they are based on patterns of Recent taxa or on theory. This study should also improve understanding of how global change can drive significant alterations in the developmental patterns of echinoids (and marine invertebrates in genera l). The work will also result in a secure phylogeny for a major group of echinoids, which can subsequently be used to explore further patterns of evolution through time.