RESUMEN
Quantitative analysis of shape and form is critical in many biological disciplines, as context-dependent morphotypes reflect changes in gene expression and physiology, e.g., in comparisons of environment-dependent phenotypes, forward/reverse genetic assays or shape development during ontogenesis. 3D-shape rendering methods produce models with arbitrarily numbered, and therefore non-comparable, mesh points. However, this prevents direct comparisons. We introduce a workflow that allows the generation of comparable 3D models based on several specimens. Translocations between points of modelled morphotypes are plotted as heat maps and statistically tested. With this workflow, we are able to detect, model and investigate the significance of shape and form alterations in all spatial dimensions, demonstrated with different morphotypes of the pond-dwelling microcrustacean Daphnia. Furthermore, it allows the detection even of inconspicuous morphological features that can be exported to programs for subsequent analysis, e.g., streamline- or finite-element analysis.
RESUMEN
Comparative morphology, dealing with the diversity of form and shape, and functional morphology, the study of the relationship between the structure and the function of an organism's parts, are both important subdisciplines in biological research. Virtual anthropology (VA) contributes to comparative morphology by taking advantage of technological innovations, and it also offers new opportunities for functional analyses. It exploits digital technologies and pools experts from different domains such as anthropology, primatology, medicine, paleontology, mathematics, statistics, computer science, and engineering. VA as a technical term was coined in the late 1990s from the perspective of anthropologists with the intent of being mostly applied to biological questions concerning recent and fossil hominoids. More generally, however, there are advanced methods to study shape and size or to manipulate data digitally suitable for application to all kinds of primates, mammals, other vertebrates, and invertebrates or to issues regarding plants, tools, or other objects. In this sense, we could also call the field "virtual morphology." The approach yields permanently available virtual copies of specimens and data that comprehensively quantify geometry, including previously neglected anatomical regions. It applies advanced statistical methods, supports the reconstruction of specimens based on reproducible manipulations, and promotes the acquisition of larger samples by data sharing via electronic archives. Finally, it can help identify new, hidden traits, which is particularly important in paleoanthropology, where the scarcity of material demands extracting information from fragmentary remains. This contribution presents a current view of the six main work steps of VA: digitize, expose, compare, reconstruct, materialize, and share. The VA machinery has also been successfully used in biomechanical studies which simulate the stress and strains appearing in structures. Although methodological issues remain to be solved before results from the two domains can be fully integrated, the various overlaps and cross-fertilizations suggest the widespread appearance of a "virtual functional morphology" in the near future.