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

海胆生命史和发育的进化：环境因素和宏观进化相关因素作用的检验

• 批准号: 9706579
• 负责人: Richard Emlet
• 金额: $ 17.46万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-10-01 至 2002-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9706579&HistoricalAwards=false
• 关键词: Evolution; Life; History; Development; Echinoids

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.

9706579 Emlet海洋无脊椎动物的生活史和发育是密切相关的——产许多小卵的物种产生可食性的幼虫，而产很少（er）、大(r)卵的物种产生可食性的、不食性的或已孵出的后代。这些特征被认为反映了生态和环境因素。尽管许多现存分类群的生活史/发育模式将被描述，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）却知之甚少。例如，一些关于腹足类软体动物化石的研究报告了生活史/发展与物种形成率和地理范围之间的相关性，但发展转变的原因仍然不清楚。本提案将研究一个具有良好化石记录的进化分支（棘皮纲，棘皮门），该分支在许多独立的谱系中进化为非浮游生物（=不摄食的幼虫或孵化）。该研究将考察在第三纪（最后65 Ma）不同的生命史/发育模式发生的地点、时间和环境条件。本研究的目的是：1)构建temnopleuoid echinoids的形态和分子系统发育，以确定在此顺序中非摄食发育进化的次数。2)研究生命史/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/发育模式向少数大卵和非浮游营养化发展转变的环境条件。将从30-40个现存和化石属或亚属中收集大约60多个字符组成的形态学字符集。将参观澳大利亚、欧洲和印度的主要博物馆，研究化石和近代类型，并收集字符集。temnopleuroids的系统发育分析将使用标准的数值分类，例如，将使用软件程序PAUP来构建最简约的树，随后将探索系统发育结构和鲁棒性。分子系统发育方面，将收集约15个棘球蚴属和亚属的28S rRNA和线粒体细胞色素氧化酶I （COI）基因的部分序列，并与已建立的棘球蚴分子数据库进行整合。DNA将被提取并用PCR扩增，基因片段将在自动测序仪中测序。在序列比对之后，系统发育树将使用简约性（PAUP）和最大似然性（PHYLIP）构建。使用全证据方法，形态学和分子数据将结合起来，以便使用上述方法估计该组的最佳系统发育树。化石和新近分类群的发育数据将被绘制到树上，以确定非浮游生物进化的次数和地点。研究人员将探索在temnopleuroids和其他已知系统发育的化石分类群之间的发育模式，以确定生命史/发育模式是否会影响海胆的物种形成率或地理范围，就像一些腹足类软体动物所显示的那样。最后，还将对生活史/发育模式转变的环境条件进行定量和统计研究。这项拟议中的研究将是第一次详细研究生命史（和发育模式）的进化，研究对象是一个拥有良好化石记录的群体，具体设置在一个真正严格的系统发育框架内。因此，本研究将提供一个发育模式的时间和空间进化史，这在很大程度上仍然是推测性的，因为它们是基于最近分类群的模式或理论。这项研究还应该提高对全球变化如何推动棘类动物（以及一般的海洋无脊椎动物）发育模式发生重大变化的理解。这项工作还将为棘类动物的主要群体提供一个可靠的系统发育，随后可以用来探索随着时间的推移进化的进一步模式。