There are less than 8 billion people presently on Earth.
Supposing a generation time is 25 years, and supposing the
H.Sapiens line is only 100, 000 years old as a species
then one can suppose there have been 4000 generations of this species.
since 1.004 ^4000 ~=8.6 billion, then we can suppose that over the long
haul,
each generation represents an effective multiplication of 1.004 at most
in the population.
By this reckoning, in 25 years, 2 people become 2.008 people on average.
This seems to mean that two people can usually produce 2 children
who survive to maturity, with a small chance 0.8% of producing three
children who survive to reproduce.
These numbers do not seem extravagantly controversial.
However, when 2.08 kids count two parents, they can count 4 grandparents,
and 8 great grand parents so that the genetic inheritance doubles for
each generation.
It seems that such doubling allows for a maximum of just 33 generations
of independent genetic contributions, according to the equation 2^33
~=8.6 billion.
This seems to imply just 33 X 25 years before all the possible genetic
inheritance is exhausted. One can easily be led to suppose that
the entire world population is related to all others as not very distant
cousins.
Any insights?