19016

I was intrigued by your article for a couple of reasons. Isn’t this what Steven J. Gould said, that evolution is punctuated by environmental stresses that can bring about adapt-or-die changes rapidly? Also, what are the implications for the geneticists who base their mitochondrial DNA dating techniques on what they consider a fairly constant rate of mutation?

Harry Walker
Pitman, N.J.

Mutations still accumulate at the same rate. The consequences of those mutations, however, may appear in bursts rather than gradually. This could indeed resemble what Gould described in his theory of punctuated equilibrium. –J. Travis