J. Matthias Starck¹ & Robert E. Ricklefs²

1Institute of Zoology and Evolutionary Biology, University of Jena, Erbertstraße 1, D-07743 Jena, Germany, e-mail starck@pan.zoo.uni-jena.de; ²Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121-4499, USA, e-mail ricklefs@jinx.umsl.edu

Starck, J.M. & Ricklefs, R.E. 1999. Developmental and ecological perspectives on growth and differentiation of avian embryos. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban: 2775.   Johannesburg: BirdLife South Africa.

Avian embryos are frequently used as a model system in developmental biology, biochemistry, clinical and immunological approaches, molecular biology, and studies of gene expression. Such a background of detailed information and new methodologies in avian embryology offers a plethora of research avenues to study the integration of developmental processes into a framework of ecological adaptation and phylogenetic history. However, beside the embryo itself the extraembryonic organs (yolk sac, chorioallantois) have a pivotal role in controlling overall rate of embryonic respiration and metabolism, and might limit egg design and length of embryonic development. The aim of this symposium is to consider the avian embryo as a growing organism and to follow the transition from the zygote to neonate. A particular guideline for the discussion of developmental pathways of structures, physiology, and behaviour is the developing diversity of avian neonates, e.g. the altricial-precocial spectrum. We will particularily aim at a discussion of the relationship between embryonic growth and maturation and focus on prenatal development at all levels of comparison: from the whole embryo, organ systems, to particular tissues.