1. Why should we engage in Developmental Biology?
To promote Developmental Biology, we should have our elevator pitches ready at all times, whenever there is an opportunity to talk about our discipline, be it to the public, students, fellow scientists or policy makers. The BSDB has started with a (brave?) first attempt at providing a concise rationale and ideas that can be woven into such conversations (bsdb.org/advocacy). We would like to turn that page into a community effort and invite you to send in corrections and ideas for improvement, additions, further arguments and potential links that will further strengthen the message we want to convey

2. Why should we study Development?
The frequency at which all classes of developmental defects occur is thought to be ... exceeding half of initial pregnancies.
Major developmental defects ... occur in approximately 3% of live births.
In 1995, major developmental defects accounted for approximately 70% of neonatal deaths (occurring before 1 month of age) and 22% of the 6,500 infant deaths (before 15 months of age) in the US.
Approximately 30% of admissions to pediatric hospitals are for health problems associated with such defects.
Source: National Res. Council: Developmental Defects and Their Causes (see 3 slides on) 2 2

3. What is Developmental Biology?
Developmental Biology is the causal analysis of the cellular mechanisms that drive processes of growth, pattern formation and morphogenesis
(A. Martinez Arias)
Developmental biology is the study of the process by which organs grow and develop... Modern developmental biology studies the genetic control of cell growth, differentiation and morphogenesis, which is the process that gives rise to tissues, organs and anatomy, but also regeneration and ageing.
(after L. Wolpert)
Glia
Neurones
Skin
White
blood cells
Red
Muscle
Fat
Liver
Developmental biology is the study of the process by which animals and plants grow and develop, and is synonymous with ontogeny (Wikipedia) 3 3

4. Fundamental questions asked by developmental biologists
and how they translate into biomedical application
What processes lead to fertilisation and the initiation of development? How can we overcome infertility and childlessness?
How do single fertilised egg cells, or later on groups of progenitor cells, generate the enormous cellular diversity of an organism and its organs and tissues? How do stem cells generate whole tissues or organs - for example in regeneration, wound healing or tissue engineering?
How do cells, which originate from common ancestors and contain the same genetic information, adopt different fates? How do cells change their identities and behaviours - for example in cancer?
How do tissues and their cells know when to stop growing? How can cells evade growth control - for example in tumour growth?
How is the formation of different cells/tissues coordinated in space and time? What are the patho-mechanisms underlying birth disorders?

5. What is special about Developmental Biology?
Developmental Biology (like Physiology) is asking fundamental questions at the level of whole organisms, organs or tissues, i.e. the level at which diseases become manifest, most effective in delivering explanations for diseases or medically relevant processes including infertility, neonatal death, birth defects (e.g. deformation, body growth abnormalities, developmental brain disorders, blindness, deafness), cancer, wound healing, tissue regeneration (regenerative medicine including stem cell biology), etc.
Developmental Biology-related research is a generator of new ideas and concepts essentially underpinning the modern biomedical sciences. Such concepts include cell signalling, tissue and body patterning, growth regulation, cell migration or morphogenesis; they form the basis for contemporary research into stem cells, cancer, wound healing, regeneration or ageing.
Developmental Biology is exciting and powerful because it reaches across the different levels of biological complexity and explanation; phenomena at the level of organisms, organs or tissues can ultimately be understood only by tracing them back to events at the level of genes and cells. Consequently, Developmental Biology embraces disciplines such as genetics, evolutionary biology, molecular biology, (stem) cell biology, biochemistry or biophysics. 5 5

6. The following chapters from the book "Scientific Frontiers in Developmental Toxicology and Risk Assessment" (2000) edited by the National Research Council (National Academic Press, Washington, DC, 354 pages) provide helpful background:
Chapter 2: Developmental Defects and Their Causes. pp
Chapter 6: Recent Advances in Developmental Biology. In "Scientific Frontiers in Developmental Toxicology and Risk Assessment" (N. R. Council, Ed.), pp National Academic Press, Washington, DC --
Appendix C: Signaling Pathways. pp