One hundred years ago, D’Arcy Thompson – a nineteenth century
polymath, working at the turn of the twentieth century – wrote a
beautiful monograph, “On Growth and Form”, in which he pondered
the geometry of living forms and how it emerges in the process of
Morphogenesis. Thompson was ahead of his time. Genetics and
Developmental Biology have since come a long way in elucidating
the general and particular aspects of Morphogenesis, uncovering the
key genes and molecules that underlie the process in different
animals and plants. Yet, Thompson’s agenda of understanding how
developmental processes actually specify the geometry of tissues,
limbs and organs is far from complete. A particular challenge is to
bridge the gap between microscopic scales, where molecular
mechanisms operate, and the macroscopic scales of animal “shape
and form”. This challenge offers much for a Theoretical Physicist to
think about. This talk will provide some examples, relating the study
of order in the arrangement of fly wing hairs to ferromagnetism and
uncovering an unexpected wealth of mechanical phenomena in the
study of cellular flows in a fly embryo.
