RE: [GZG] Need help, Colony population #'s

G'day,

You don't want to have to grapple with the models I use in my job, but I
do have some stuff I'm happy to hand out.

You can do very simple population dynamics modelling in a single sheet
in excel (which I can give you) - it takes into account migration, birth
rates, mortality social welfare system type (which governs how the
population reacts as it approaches carrying capacity - or the total
amount the currently available resources can support). 

If you're willing to go multiple sheets then I can also give you a
matrix population model I use to teach a class here. It has explicit age
and sex structure so that you can see the problems of aging populations,
imbalanced sex ratios and can also explicitly see what work force you've
got to draw from for you military etc.

At some point in the future (probably towards the end of the year) I'm
going to write a simple c++ metapopulation exe (so for our purposes the
migrants get tracked, at present most space colony models assume that
migrants are there for the having without checking the numbers add up
and we're not assuming an infinite migrant pool) which I was going to
give my class and the 10 Worlds (Attack Vector) folks. 

As to population viability, which is what I think you're talking about
you want a few hundred thousand at least and reasonably high human
growth rates (3% birth rate is high for humans, we're more typically
about 2%). Less than that (and especially less than a few thousand) then
you'll get into the realm of genetic bottlenecks (which aren't
immediately catastrophic, Iceland for instance didn't go belly up, but
does leave you open to an epidemic overwhelming the population) and
biased catastrophic mortality effects (where a catastrophe takes out
your entire breeding base etc).

The exe files can get quite large so it may be best if I posted them on
my ftp site. I can't do that from home, but will do it early in the week
and let you know. 

Ultimately though unless you really want to have the fun of playing with
the models Laserlight's plausible story telling approach is fine, just
keep in mind whats plausible given the colony size you're after ;)

Cheers

Beth

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