AVIAN EGGSHELL: ENGINEERING AND EVOLUTION OF A REMARKABLE MULTIFUNCTIONAL MATERIAL
Abstract
Avian eggshell is an extremely multifunctional material. It evolved to balance external challenges with internal requirements. It must be strong enough to withstand physical damage but weak enough to allow a chick to hatch. It must also resist microbial invasion yet be sufficiently porous to facilitate gas exchange. In many cases, the eggshell is pigmented for camouflage or signaling, but it must not over- or under heat. How have birds, over 150 million years of evolution, produced an eggshell that fulfills these diverse and often conflicting demands? What are the material design rules for achieving its mechanical robustness, lightweight nature, breathability and ultimately breakability? Currently, eggshell remains understudied as a potential model for developing novel functional composite materials. In this proposed collaborative research, we will investigate eggs laid by the oldest living birds: the paleognaths. This group includes many flightless species, such as ostriches, rheas, kiwis, cassowaries and emus, plus a group of flying birds called tinamous. The eggs laid by paleognaths have extremely diverse shapes, sizes, surface textures, ultrastructures, and colors, making them an ideal group for studying different eggshell design strategies. Our first goal is to understand how eggshells fulfill the dual mechanical challenges of resisting fracture but ultimately facilitating breakage, to allow the chick to hatch. We will combine state-of-the-art structural analysis, synchrotron in situ imaging and multiscale mechanical modeling to understand how eggshells fracture. Our second goal is to integrate eggshell mechanics into a broader assessment of the egg’s multifunctional design, incorporating data relevant to diverse physiological and optical functions of eggshell. We will perform comparative analyses to determine how paleognaths evolved eggshell designs fine-tuned to their precise ecological requirements.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2021
- Source ID
- FA95502010161
Entities
People
- Mary Stoddard
Organizations
- Air Force Office of Scientific Research
- Trustees of Princeton University
- United States Air Force