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ABSTRACT Embryonic development is fascinating to follow and highly engaging and, therefore, lends itself for undergraduate students’ first steps in experimental science. We developed the “Trails to Research” inquiry-based course, which exposes students to life science research using zebrafish as model organism. Zebrafish are ideal in the classroom: they are easy to maintain, their embryos develop rapidly, and they are easily manipulated. Further, they lend themselves to teach about embryo development and experimental design. We developed the course for undergraduates at 2-year colleges and, therefore, for students with little or no research experience. In this 5-day intensive course (which is taught during summers as a stand-alone course), students design treatment experiments for zebrafish embryos with known teratogens and with substances they select. The course comprises three modules that overlap over the 5 days: (i) introduction to developmental biology, model organisms, toxicology, and experimental design, (ii) zebrafish embryo experimental setup, and (iii) collecting, analyzing, and presenting data. Student learning was significant in the areas of experimental design, working with model systems, working with zebrafish embryos, using laboratory equipment, and presenting the results of their experiments using effective methods. 

Abstract The avian transition from long to short, distally fused tails during the Mesozoic ushered in the Pygostylian group, which includes modern birds. The avian tail embodies a bipartite anatomy, with the proximal separate caudal vertebrae region, and the distal pygostyle, formed by vertebral fusion. This study investigates developmental features of the two tail domains in different bird groups, and analyzes them in reference to evolutionary origins. We first defined the early developmental boundary between the two tail halves in the chicken, then followed major developmental structures from early embryo to post-hatching stages. Differences between regions were observed in sclerotome anterior/posterior polarity and peripheral nervous system development, and these were consistent in other neognathous birds. However, in the paleognathous emu, the neognathous pattern was not observed, such that spinal nerve development extends through the pygostyle region. Disparities between the neognaths and paleognaths studied were also reflected in the morphology of their pygostyles. The ancestral long-tailed spinal nerve configuration was hypothesized from brown anole and alligator, which unexpectedly more resembles the neognathous birds. This study shows that tail anatomy is not universal in avians, and suggests several possible scenarios regarding bird evolution, including an independent paleognathous long-tailed ancestor.