Fluid Dynamics in Developmental Biology: Moving Fluids that Shape Ontogeny

Human conception, indeed fertilization in general, takes place in a fluid, but what role does fluid dynamics have during the subsequent development of an organism? It is becoming increasingly clear that the the number of genes in the genome of a typical organism is not sufficient to specify the minutiae of all features of its development. Instead, genetics often acts as a choreographer, guiding development but leaving aspects - especially morphogenesis - to be controlled at an epigenetic level by physical and chemical means. Fluids are ubiquitous in biological systems, so it is not surprising that fluid dynamics should play an important role in the physical and chemical processes shaping development. However, only in a few cases have the strands been teased apart to see exactly how fluid forces operate to guide development. Here we review instances in which the role of fluid dynamics in developmental biology is acknowledged, both in human development and within a wider biological context, and we provide a fluid dynamicist\\\'s perspective on possible avenues for future research.