M�LLER, G.B.: Activity-Induced Cartilage and Bone Formation: A Factor in Evolutionary Innovation

Externally or internally caused activity changes of the embryo have immediate consequences on cartilage and bone formation via mechano-sensitive connective tissue and cartilage cells. The presentation will deal with three topics: Part one will discuss external modifiers of embryonic activity, with a focus on illumination changes. Part two will present data on experimental modifications of embryonic activity and its effects on the development of the skeletal system, with a focus on sesamoid formation. Part three will discuss the evolutionary consequences of such reactive properties of the developing skeletal system. It will be proposed that environmental changes and/or selection on body proportions can have a strong influence on the biomechanical conditions in the developing skeletal system, with the potential to cause evolutionary innovations as a byproduct of such changes.