The average mutation rate among living beings is on the order of one in 100,000 gametes (sperm or egg).

• A mutation rate that is too low prevents significant change between generations ==> evolution stagnates

• A mutation rate that is too high results in offspring that have little (if any) resemblance to their parent, and are less likely to be improvements ==> evolutionary chaos

Fortunately (and wonderfully) the typical thermal energy in a living organism is smaller than, but comparable with, the DNA bonding energy.

• "smaller than" allows the mutation rate to be not too high (DNA relatively stable over short time periods ==> avoids chaos)

• "comparable to" allows the mutation rate to be not too low (DNA molecule changes gradually over long time periods ==> avoids stagnation)

This is a specific example of the fact that

if any of the three numbers in the Schrodinger equation ---

Planck's constant:  h

the electron's mass:  m_e

the electron's charge:  e

--- were even slightly different,

our physical world would by profoundly changed!

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