ECONOMICS

The main factor that determines how many Population Points maximum a region can hold is the size of the planet as shown below:

The Regional Maximum Population Limit is modified by the following:

The Habitability Zone that the planet resides in for the species of population in that region multiplies the above value as shown below:

The Ecosystem Density of that region also multiplies the above Regional Maximum Population Limit as shown below:

Finally, two regional buildings will directly add 1 or 2 to the Regional Maximum Population Limit when built in that region. Note that these cannot be built for population groups living in a biosphere (see "Biospheres")

Population growth occurs automatically (working three decimal places to the right of the number shown on screen). Growth is calculated per population center and is based on several factors (the availability of food, environment, racial tendencies, growth enhancing/restricting events and technologies, etc.).

Population growth uses a combination of old and new. The basic growth formula depends upon the current population of the region, the race's base rate of growth in the region, and the maximum population of the region. It's a familiar combination to MOO1 fans; population growth occurs most quickly when the region is neither too empty nor too full. There are two formulas that control growth:

There is a quick and dirty overcrowding scale that can be applied to every region on a planet as well as a planet as a whole.

When a region or planet is at or below 75% of its Maximum Population [determined by: 1) size of planet; 2) Habitability Zone the planet is in; and 3) the Ecosystem Density, see above], it is below its "Natural Population Limit" and is said to be in its Population "Green Zone."

When a region or planet is above 75% and at or below 90% of its Maximum Population, it is within its "Natural Population Limit" and is said to be in its Population "Yellow Zone."

When a region or planet is above 90% of its Maximum Population and at or below its Maximum Population, it is within its "Crowded Population Limit" and is said to be in its Population "Red Zone."

When a region or planet is above its Maximum Population, it has reached its "Overcrowded Population Limit" and is said to be in its Population "Black Zone."

When there is not enough food to feed a region, it’s population is either "hungry" or "starving."

When half or more of the food requirements are met, the population is merely hungry and their growth rate is reduced proportionally to the level of food shortfall. Thus, with exactly half the needed food coming in, there is a 0% growth rate on that region.

When less than half the food required arrives, there is starvation. This gives that region a ‘death rate’ to worry about instead of a ‘birth rate’ because people are dying faster than they’re being born. The death rate proportionally increases with the shortfall of food up to five times what the opposite of the maximum growth rate for that region would be based on its fertility only. That is, on a 1% to 5% scale, if people were growing at 1%, they’d starve at a five times the 5% rate and vice-versa. The net effect is that the more people in a region, the faster they’ll die off. If there’s few people in a lush area, they’ll starve very slowly indeed.

When a planet isn’t habitable to a race, the population there must live in a controlled (or "enclosed") environment dubbed a "biosphere." Note that a biosphere functions in MOO3 as a concept, not as a "building" per se. Any population group living under the harshest conditions is automatically assumed to be living in a biosphere.

Every population group residing on a planet that is in that species’ Yellow 2 or Red Habitability Rings is considered living in a biosphere.

Of course, there are some game rules affecting population groups that are, by definition, living in biospheres. These appear below:

Perhaps the greatest drawback to biosphere living is that maintenance costs for that population group and any improvements in that region are exorbitant.

<Formula not included>

No "outdoor" bioharvesting takes place in a region in the outer Yellow or either Red Habitability Ring. Essentially, the population group living there must import all the food it eats.

There are two Technology Achievements that ameliorate this situation. One, Bio-morphic Fungi, permits bioharvesting by one additional Habitability Ring. The other, Mineral-morphic Fungi, permits bioharvesting two additional Habitability Rings. When a civilization has both of these, therefore, it can bioharvest all the way into the outer Red Habitability Ring.

Designer’s note: The guys in the "Red Zone" still live in biospheres, but at least they can grow their own food with these achievements.

In addition, Hydroponic Farms and Subterranean Farms are fully functional in biospheres. They add +½ and +1 unit of bioharvest unit each turn, respectively, even when placed in a Bioharvesting DEA that is built in a biosphere.

No population will voluntarily move to a region where it will be living in a biosphere. That is, no migrants, immigrants, nor pioneers will settle there. If a civilization wishes to establish population groups in a biosphere living conditions, they must be brought over in outpost and colony ships and deposited there.

Population living within a biosphere environment can grow naturally. Usually, such population groups grow at the rock-bottom (1%) population growth rate.

On top of everything else, the maximum population limit for a region requiring biosphere living is only 1 Population Point.

There are two Technology Achievements concerning the maximum population limit of a civilization’s biospheres. A late-beginning game achievement raises the maximum by 0.33 Population Points, while a mid-game achievement raises it by 0.67 Population Points (but never greater than it would naturally be in the outer Yellow Habitability Ring). Thus, a civilization that achieves both of these advances will enjoy biospheres that can house up to 2.0 Population Points each.

Note that two buildings (listed below) that add directly to the Regional Maximum Population Limit cannot be built for population groups living in biospheres.

In addition to their role serving the labor needs of a planet’s economic capacity, each population point produces 3 Cement units and 1 Test Tube unit per turn. The formulas for each population point are as follows:

Population points do not directly generate money. Instead, the value of all the goods they produce that do generate pre-tax income that is computed into that planet’s GPP (see "Gross Planetary Production").