A close look at the animation reveals that a face forms from three main features that rotate into place, meeting at the philtrum, the groove above the top lip. The transformation occurs with very precise timing and delays can result in a cleft lip or palate.Doubtless, however, mutations occurring at precisely the right time and selected for by natural selection can explain how it all turned out swimmingly for human embryos so that cleft palates became the exception rather than the norm:
Friday, July 6, 2012
Till We Have Faces
The title of this post is an allusion to a book by C.S. Lewis whose title popped into my head as I watched this video at New Scientist. It's a brief but fascinating time-lapse based on human embryo scans captured between 1 and 3 months after conception as the embryo's face develops. The article tells us that:
