The processes of life work at many different speeds. Some occur swiftly, others require millions of years; some recur in a cyclical manner, others are historically unique. The two great processes of biological creation are embryological development and organic evolution. Development fits into the rapidly recurring category, while evolution fits into the complementary category of the unique and time-extended.

However, in the world of life, always beware of generalizations. It is science's duty, and its pleasure, to attempt them; but they are often wrong or, at the very least, subject to some ifs, buts, and exceptions. It takes a long time to develop a blue whale or a Californian redwood from a fertilized egg. That space of years is more than enough for a microbe with a generation time of half an hour to evolve resistance to penicillin. So the developmental and evolutionary timescales overlap, but not by much.

Both of the two great processes of biological creation have their historical heroes, though those of evolution tend to be better known than those of development. Darwin and Wallace spring more readily to most layminds than Fabricius or Roux. The heroes of genetics are important too, as genes underlie both processes; so we are also indebted to Mendel, Watson and Crick.

But I am more concerned here with the present and the future than with the past. For a quiet revolution is beginning in biology, and as yet its heroes are relatively unsung. While studies on development and on evolution were carried out in relative isolation for most of the twentieth century, today there is a thrust towards synthesis.