Duration of Development of Planktonic Embryos

9633193 Strathmann许多门的动物将卵释放到浮游生物中，在那里它们在没有亲代保护的情况下发育。它们发育到第一次游泳的时间比有更多受保护胚胎的相关物种要短。自然选择似乎倾向于它们短时间游泳，但时间各不相同。在这项研究中，四个问题将通过海洋动物群体内部和群体之间的比较来回答。(1)胚胎发育到第一次游泳的时间是否与运动结构中细胞的数量有关？(2)这一持续时间是否更强烈地受到门内功能差异的影响，例如是否存在摄食幼虫期或卵的大小？(3)在第一次游泳之前，受到更多保护的胚胎是否发育得更慢（除了发育时间更长）？(4)发育到第一次摄食的持续时间与用于纤毛摄食的结构中的细胞数量有关吗？这项研究可能会证明在胚胎持续时间和这些限制的功能原因的收敛异常持久的限制。或者，这项研究可能表明，不同形式的动物以不同的方式趋同于相似的胚胎持续时间。这两种结果都将表明海洋动物在其生活史中如何通过单细胞瓶颈的进化枝特异性限制。

9633193 Strathmann Animals in numerous phyla release eggs into the plankton where they develop without parental protection. Their development to first swimming is briefer than in related species with more protected embryos. Selection appears to favor their short time to swimming, but the time varies. In this research, four questions will be answered by comparisons within and between groups of marine animals. (1) Is duration of embryonic development to first swimming correlated with the number of cells in locomotory structures? (2) Is this duration influenced more strongly by functional differences that occur within phyla, such as presence/absence of a feeding larval stage or egg size? (3) Do more protected embryos develop more slowly (in addition to developing for a longer time) before first swimming? (4) Is duration of development to first feeding correlated with numbers of cells in structures used for ciliary feeding? This study may demonstrate extraordinarily persistent limits on convergence in embryonic durations and functional reasons for those limits. Alternatively, this study could show that diverse forms of animals have converged on similar embryonic durations in diverse ways. Either outcome will indicate clade-specific constraints on how marine animals pass through the one-cell bottleneck in their life history.