Developmental biology and evolutionary biology are both mature integrative disciplines which started …

• Abstract
• Introduction
• Three major questions in biology: what, how, why?
• Historical overview: the evolutionary theory at the beginning
• The evolutionary tree of life
• Multicellularity - a major recurrent evolutionary change
• Explaining the origin of multicellularity
• Analogies and homologies
• The origin and evolution of developmental novelties
• The antero-posterior axis: a major success of developmental genetics
• Another developmental and evolutionary paradigm: the origin of the eyes
• Sexual reproduction: a poorly understood and recurrent evolutionary dilemma
• Concluding remarks
• Acknowledgements
• References

I thank Drs. F. Dieterlen and N.M. Le Douarin for helpful comments on this essay, and H. Legout for help in the preparation of the manuscript.