Evolutionary Rate Units

 

Definition of a darwin (d):

a change by a factor of e per million years.

 

 

Definition of a haldane (h):

a change by a factor of one standard deviation per generation.

 

 

  • where ln x1 and ln x2 are two sample means of natural logarithms of measurements,
  • sln x is the pooled standard deviation of the ln x1 and ln x2 values,
  • delta t is the time difference between the two samples in millions of years, and
  • t2 - t1 is the time difference between the two samples, measured in generations.