Population growth

[LostSoul]

Umm...1 mom and dad, who have at least one child, and 1 uncle with 1 child: 1st "kissing" cousins. So 5, not including the woman who the uncle impregnated.

People in small, rural towns do that calculation all the time.

Is that enough genetic diversity to begin a community?

 

[alsih2o]

Is that enough genetic diversity to begin a community?

I have heard that it takes 136 people.


Of course, my numbers come from a Star Trek episode....

 

[NewJeffCT]

The one problem I see with clerics here is that in reality, when a virus goes around your local school or office, everybody gets affected around the same time - basically, within a week or two of each other. If, in 5 years, the population of this nation has grown from 100 to 150, what happens if suddenly 50 of them get sick with some strange new virus in the same week? Would a cleric be of high enough level to cure all of them before at least some died? I kind of doubt there are antibiotics around to keep a month old child alive long enough so the cleric can rest & then pray for his or her spells after just curing two other children earlier. In my gaming worlds, I usually do not have more than 1 spellcasting cleric per 1,000 population, let alone per 100. This also does not take into account the cleric being of high enough level to cast cure disease as well, which is not a first level spell if I recall.

Also, is this a typical cross section of 100 people from Wales, or is it 50 fertile mating age females and 50 fertile mating age males? A typical cross section of people will include children too young to have children yet, as well as at least a few women too old to bear children anymore, not to mention a few homosexuals and some women that can't have children and some men that can't father them.

 

[NewJeffCT]

I have heard that it takes 136 people.


Of course, my numbers come from a Star Trek episode....

I remember that episode. Wasn't there some feisty Irish sounding redhead that Riker had an affair with?

But, you also make a good point about genetic diversity. Is 100 enough people?

 

[MerakSpielman]

I remember that episode. Wasn't there some feisty Irish sounding redhead that Riker had an affair with?

But, you also make a good point about genetic diversity. Is 100 enough people?

It is if Cure Disease can cure genetic disorders, too!

 

[The_Universe]

I have heard that it takes 136 people.


Of course, my numbers come from a Star Trek episode....

I remember that episode!

Also, assuming that there's no further migrations to the area by other populations, it's literally true. You need 136 healthy people, evenly distributed between male and female, to avoid having to deal with "line breeding." It's not just Star Trek, and nor is it merely to avoid "kissing cousins." 1st cousins marrying, though a potential problem, is only the beginning. Even if you can avoid the appearance of a familial relationship, without at least that many people (or, as I mentioned, another population bringing in fresh blood), you'll eventually run out of lines that have not already bred together at least once, even if they're not 1st cousins.

It's very common in domesticated livestock, which is why many ranchers (in real life) have turned to using artificial insemination to bring in fresh bloodlines to herd.

It was also very common in the European nobility, but I don't want anyone to think I'm comparing them to domesticated livestock...

 

[evildmguy]

Can I just add a real life example that starting with my grandparents (bless their souls) born in 1910 (grandfather) and 1911 (grandmother) who had 19 children (17 reaching adulthood) I have 98 first cousins (a few now deceased).
I've lost count but the family is now at the 6th Generation and has around 400 members.

Now thats in less than 100 years with a starting population of 2 with an average lifespan which is unfortunately less than 60yrs for males, more for females.
So assuming the 400 current members have an average of 1 children every 25 years (as opposed to 5.7 for the original cohort) we could have 6400 people after 200 years and thats from a base population of 2

multiply by 100 we get 640000 adjust that to the carrying capacity of the land (ie guess a good number) and yep its all good

Um, these numbers are slightly wrong, only because unless the 17 children that reached adulthood married each other, they would have brought in 17 outsiders. Further, each of their kids would also have brought in an outsider as well. So, I am not doubting your numbers, but I think you forgot a few factors in there. (Also, what about step or half siblings? Did you account for those?)

Have a good one! Take care!

edg

 

[evildmguy]

A lot of good things here.

The OP needs to consider:

-Genetics. Does he care about this? If so, there will be a higher number of genetically hereditary diseases. This means that if a disease hits that one is susceptible to, many will be hit by it.

-Magic, both clerical and arcane. How do these help? How much do these play out? According to 3.0 DMG on figuring a basic town, 100 people is a hamlet. The cleric is a d6 + commnity modifier, which for a hamlet is -2. So, Cure Disease, being a 3rd level spell, is out of reach for this (random) community. Yes, if the OP wanted to bring in a higher cleric, as this is a special case, that is up to him. (Wizard and Sorcerer are d4 - 2, with a number of 0 or less meaning not present, so there is not much arcane power here, again in a random sampling.) Further, I think Cure Disease is by individual, so if a group catch something, a lot of them will die before a cleric can get to them all.

-Gods - Do the gods stop disease and make them healthy and fine for a couple of generations? Do they slow them down? Do they do anything?

-Other "normal" factors. Immigration, emigration, war, disease and other factors that affect the population as a whole, or the birth and death rates.

-The most important, imo, - The needs of the campaign. What do you need, as the DM, for this adventure? What are you trying to set up? What are your future needs? If you want two or three cities spread out, then you will use the reasons given for a high growth rate at the beginning which slowed down later. If you want the one town two hundred years later, whatever number you pick will have been a small growth rate.

btw, this is experience talking. I started my own world very similar to how you started yours. I took cities, though, and moved them from one world to another as a "do over." I then figured each population, as I was planning my long term campaign (over 2400 years), I let the numbers talk. BAD IDEA, I found out. It would have been better for me to choose what I needed for the story at each point, rather than use some calculator to figure things out for me.

A few coppers worth.

Have a good one! Take care!

edg

 

[Sarellion]

take a number you are comfortavle with now and don´t specify the number of settlers. The tales tell of a hundred or another nice number that sounds good in a story.

Just too big of a headache.

 

[Nathal]

The OP needs to consider:

OP? That's a term I haven't heard. Oh..."original poster."

-Genetics. Does he care about this? If so, there will be a higher number of genetically hereditary diseases. This means that if a disease hits that one is susceptible to, many will be hit by it.

Nah, because this is not a sci-fi world I won't worry about genetics.

-Magic, both clerical and arcane. How do these help? How much do these play out?

I think I really need to figure out exactly how many men and women, plus how many spellcasters capable of healing there were. And, seemingly, I should have more people than 100. Because I want to end up with a kingdom after a span, and enough time to forget most of their old earth customs and religions, I think I ought to set the initial population at 200, and increase the span of time on their new realm to 500 years. These 200 people are exiles, magically transported to another reality by the magic of an enemy.

Yes, if the OP wanted to bring in a higher cleric, as this is a special case, that is up to him.

The entire initital community were spellcasters, although not all of them capable of healing magic. Most were elementalist types, closer to druids in religion. Some of them would have been priests of the celtic gods. Say 10% of them. Most of them were men...uh, oh...if even 20% of them (if I assume 200 people now) were women, there still wouldn't be more than twenty at first. Better than one I suppose, or we would have a problem tanamount to the smurfs (but no mushroom huts).

Further, I think Cure Disease is by individual, so if a group catch something, a lot of them will die before a cleric can get to them all.

I agree with that.

-Gods - Do the gods stop disease and make them healthy and fine for a couple of generations? Do they slow them down? Do they do anything?

The celtic gods do protect these new arrivals on thier new plane to some small extent, but uphold a sort of "hands off" approach to appease the other pantheons of Earth.

-Other "normal" factors. Immigration, emigration, war, disease and other factors that affect the population as a whole, or the birth and death rates.

There are no other humans in the new realm, only fantasy races and monsters. Some half-breeds are possible. No real emigration since the land becomes more real only as it's explored (kinda like in the shadow realms outside castle Amber from the Nine Princes in Amber book by Roger Zelanzy)

-The most important, imo, - The needs of the campaign. What do you need, as the DM, for this adventure? What are you trying to set up? What are your future needs? If you want two or three cities spread out, then you will use the reasons given for a high growth rate at the beginning which slowed down later. If you want the one town two hundred years later, whatever number you pick will have been a small growth rate.

One city with a population of 25,000 or above and three towns of 8,000 or so. I was trying to work my way backward to see how long ago I could make the founding of the kingdom, when the first people were sent to that land in exile.

btw, this is experience talking. I started my own world very similar to how you started yours. I took cities, though, and moved them from one world to another as a "do over." I then figured each population, as I was planning my long term campaign (over 2400 years), I let the numbers talk. BAD IDEA, I found out. It would have been better for me to choose what I needed for the story at each point, rather than use some calculator to figure things out for me.

I like the calculators to get somewhere in the ballpark, but this excercise has proven that population growth can create radically different outcomes depending on what factors you feed into it. Fun to talk about though.