Egg Morphology at the Nanoscale
Eggs are multifunctional structures that have enabled animals to colonize terrestrial habitats for millions of years. Egg morphology, particularly eggshell nanostructure, is at the core of animal survival, mediating the interactions between embryos and their environment, and has evolved into a massive diversity of forms and functions in modern taxa. These functions are critical to embryonic survival, have profound effects on animal evolution and may serve as models for new antimicrobial and/or breathable materials.
Nevertheless, we lack essential knowledge on the basic properties of eggs, including their ultrastructure, chemical composition, and material properties. These data are critically needed if we are to understand their effects on evolution and diversification of animal lineages. Here, I showcase our research on the relative contributions of structural constituents and chemistry of eggshells to their biomechanical performance using squamate and stick insects as study systems.
I combine techniques to characterize eggshell structure (i.e. X-ray micro-Computed Tomography (μCT) coupled with scanning electron microscopy), with the analysis of eggshell chemical composition using FTIR. Bridging form to function, I then present our findings on the functional performance (optical, mechanical, interaction with water) of these eggshells and finish by revealing the insights we have gained about the evolution of these remarkable egg structures and their impact on animal fitness.
History, Novelty, and Function: Cases from Beetles and Wasps
In this talk I will introduce the beetles (Coleoptera) and pincer wasps (Hymenoptera: Dryinidae) as evolutionary morphological systems for understanding the dimensions of history, anatomical identity, and function.
Using the early evolutionary history of the Coleoptera as the first of two case studies, I will contrast the deepest fossil record of this group to the Hymenoptera and use phylogenetic methods to test hypotheses of fossil placement and transformation series. In so doing, I will highlight the evolutionary patterns of Coleoptera that demonstrate the need for deciding criteria for the determination of homology and character polarity.
In the second case study, I will define a new system for the study of novelty and function: The grasping mechanism of Dryinidae. I will define the system anatomically and mechanically, which involves the recognition of new biological characters and the modified states of inherited characters. By tracing the derivation of form and function across the phylogeny of the group, I will contrast plesiomorphy and apomorphy of states versus the origin, inheritance, and extinction of characters.
Finally, using these two systems, I will reflect on the insights that can be provided by a phylogenetically informed and systematic-phenomic approach to evolutionary developmental biology.
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Presenting work done in collaboration with Rolf G. Beutel [Institut für Zoologie und Evolutionsforschung, Jena], Thomas van de Kamp [Institute for Photon Science and Synchrotron Radiation (IPS), Laboratory for Applications of Synchrotron Radiation (LAS), Karlsruhe Institute of Technology (KIT)], and Carly Tribull [Farmingdale State College, USA], among others.
