population growth

> Date: Fri, 13 Oct 2000 07:53:28 +0200
> > You are still displaying Terra-centric thinking!
> <snip>
> >The EARTH is important!
>
> Let's say the colony Hypothetica starts off with 1 million 
> colonists in 2070.
> Large families are highly valued so each couple has 8 children
> --1 every 2.5 years starting at age 20 (and we'll assume all 
> colonists are 20 when they arrive and none have their own kids).  
> The incidence of twins, triplets, extra kids above 8, etc,  
> cancels out the effects of infant mortality.
> Everyone lives to be 80.
> Immigration after initial colonization is negligible.
>
> How many people are there in 2190?

Quick and Dirty and even more simplified calculation:

Assume 4 children / person (same as 8 oer couple)
born simultaneously when the parents are 30 years of age.
First parent generation arrives at 30 years of age, first batch of 
children are born in year 1 = 2070
the 121 years until 2191 allow for 5 generations.
 
Thus: total number of children born = 4^5 * 1 million = 1024 million
The original settlers and the first two generation of planet-borns will 
have died. Subtract 1 + 4 + 16 million = 21 million people (almost 
negligible compared to recent generations)
 
Total population of the order of one bilion people ( 1 000 000 000 ).
Repeat for several planets, and they may indeed outweigh Earth's
population.

However, I think the above assumptions are VERY optimistic

Moving one million people is no mean feat.
Sustaining such extreme population growth over such a long period will 
be very hard. Will agriculture, schools, health care, general 
infrastructure be able to keep up ?
AFAIK, all historical human populations had either lower life 
expectancies or lower birth rates than those assumed above.

North and South America eventually reached population levels similar to 
the parent continent Europe, but there was sustained, fairly massive, 
migration over more than a century. Also the N+S American total is
rather 
less than a Billion 

Greetings
Karl Heinz