Interdisciplinary research on hemichordate evolution

我们从哪里来？我们的祖先是什么？我的研究项目集中在后口动物的进化上，后口动物是包括脊椎动物（和人类）在内的动物生命树的主要分支。后口动物由三个主要门组成：棘皮动物（海胆，海参和它们的表亲），半索动物（橡子蠕虫和翼鳃动物）和脊索动物（包括脊椎动物）。我最感兴趣的是后口动物进化中的深层事件，包括这样一个问题：基部后口动物的本质是什么？我的研究表明，祖先的后口虫可能类似于肠呼吸道半索动物蠕虫。我的研究计划使用多学科的方法，包括有机体和分子生物学，流体力学和古生物学来验证这一假设。 在接下来的五年里，有四个领域，我的研究将被应用于评估假设的enteroprostist一样的基础后口。首先，我们最近在肠化石中发现的生物矿物可能是一种古老的特征，在某些水平上似乎与棘皮动物的生物矿物骨架同源。第二，半索动物翼鳃类，其独特的触手喂养武器将代表一个派生条件从咽过滤器喂养的祖先。这种变化的进化压力可能与流体动力学和生物体大小有关（翼鳃类是小型生物）。第三，半索动物的口前结构（肠鳃类的口前纤毛带和翼鳃类的红带）可能与脊椎动物的腺垂体同源，腺垂体是调节应激、生长和生殖的垂体前叶区域。第四，我们将证明橡子蠕虫是一个古老的群体，化石首次出现在寒武纪时期-将其化石记录推回到近3亿年前！这项研究将推进我们对进化历史的基本认识。此外，开发的技术和工具将推动流体力学领域的发展，包括它在生物系统中的应用。

Where do we come from? What is our ancestry? My research program is focused on evolution of the deuterostomes, that major division of the animal tree of life that includes the vertebrates (and man). Deuterostomes consist of three major phyla: the echinoderms (sea urchins, sea cucumbers and their cousins), hemichordates (acorn worms and pterobranchs) and chordates (including the vertebrates). My greatest interest is in deep events within deuterostome evolution, including the question - what was the nature of the basal deuterostome? My studies have suggested that the ancestral deuterostome may have resembled an enteropneust hemichordate worm. My research program uses a multidiscipinary approach, including organismal and molecular biology, fluid mechanics, and paleontology to test this hypothesis. Over the next five years there are four areas where my research will be applied to evaluate the hypothesis of an enteropneust-like basal deuterostome. First the biominerals we recently discovered in enteropneusts could be an ancient character and at some levels appear homologous to the biomineral skeleton of the echinoderms. Second, the hemichordate pterobranchs, with their unique tentacular feeding arms would represent a derived condition from a pharyngeal filter-feeding ancestor. The evolutionary pressure for such modification may relate to fluid dynamics in relation to organismal size (pterobranchs are small organisms). Third, it is plausible that the pre-oral structures of hemichordates (pre-oral ciliary band of enteropneusts and red band of pterobranchs) could be homologous with the vertebrate adenohypophysis, the anterior pituitary region that regulates stress, growth, and reproduction. Fourth, we will demonstrate that acorn worms are an ancient group, with fossils first appearing in the Cambrian period - pushing back their fossil record nearly 300 million years! This research will advance our basic knowledge of our evolutionary history. Moreover, techniques and tools developed will advance the field of fluid mechanics, including it's application to biological systems.