Darwin (unit)

The Darwin , named after the British naturalist Charles Darwin , is a unit used in evolutionary research. It was defined by JBS Haldane in 1949.

Darwin is defined as the change in a characteristic by a factor of e (about 2.718) over a period of 1 million years.

equation

The equation for calculating evolutionary change ( ) is: ${\displaystyle r}$

${\displaystyle r={\frac {{\rm {ln}}X_{2}-{\rm {ln}}X_{1}}{\Delta t}}}$

where and start and end values ​​of the characteristics and the change in time is in millions of years. An alternative form of the equation is: ${\displaystyle X_{1}}$ ${\displaystyle X_{2}}$ ${\displaystyle \Delta t}$

${\displaystyle r={\frac {{\rm {ln}}{\frac {X_{2}}{X_{1}}}}{\Delta t}}}$

Since the difference between two natural logarithms is a dimensionless relationship, the feature can be measured in any unit . For this reason too, Darwin is a special form of the inverse mega-annum ( ). ${\displaystyle Ma^{-1}}$

Individual evidence

1. ↑ JBS Haldane: Suggestions as to quantitative measurement of rates of evolution . In: evolution . Vol. 3, No. 1 (March 1949), pp. 51-56.