Numbers in colonization and ground invasion?

Most military campaigns involved a HUGE percentage of Support personnel.  The actual fighting force, the "tip of the spear", amounts to only about 10% of the total manpower.  Similarly, on a planetary defense, though technically the entire population is enrolled in the National Guard, planetary militia, Volks Grenadiers, whatever, the actual combatants are a much smaller number.  And on the defense, most won't even see combat because most are deployed in defensive positions that never see combat.  ["The Attacker gets to choose where to apply the bulk of his military might.  The Defender, on the other hand, must try to defend everywhere."  It's why offensive geniuses like Napoleon and Frederick the Great so often defeated much larger nations and armies.]

Given that population more or less directly translates to production capacity, it's much more likely that a planet's population is the number of working-age adult citizens (a class of people which mostly overlaps with military-age adult citizens) on the planet than to the total number of people upon the planet. The population growth is also linear rather than exponential or exponential modified by population pressure and available resources, suggesting that something unnatural, say spaceport throughput, is the primary factor involved in population growth rather than natural births and deaths (yes, there's the 'birthing subsidies' project, and the population growth line of the tech tree has techs which are given names and descriptions indicating that the population growth should be a function of natural births and deaths, but the actual growth rate really doesn't reflect that).

For that matter, it's arguably the case that a planet's population represents the total number of government employees on the planet rather than the planet's actual population. After all, planetary population is one of the main determinants of the output of factories, research labs, markets, et cetera which were built by the state and are maintained by the state. The factories furthermore provide the state with production at what is generally a significantly lower cost per point of production than the rush purchase costs would suggest, even if you build in a fudge factor for the extra expense of doing something quickly (okay, fine, there are conditions where a point of manufacturing may 'cost' a number of credits equivalent to or perhaps even greater than the rush cost, but that's a relatively exceptional circumstance requiring the wealth multiplier to be 10 or more times the manufacturing multiplier). And finally, there's the wheel in the govern planet screen (or the empire-wide one, if you'd rather use that), which looks like a spending allocation chart more than anything else.

If you accept the ship dimensions given within the game and you assume that the population numbers are in the billions, then a single colony ship cannot fit the number of people that it is supposed to carry, and the options for reducing space requirements for carrying the billions of people a colony ship is supposed to carry are limited. The time is far too short for it to be practical for the ship to reduce space by carrying embryos, infants, or small children, as they'll take too long to meaningfully contribute to the colony's production and yet a colony with a population of 3 and a given set of output multipliers has the same output whether it was founded this turn or 20 turns ago or 2000 turns ago.

How do you know there isn't a mixed population on the planet? GCIII doesn't track population by species, and the indications I see suggest population is more in line with the number of working-age or military-age citizens or even government employees than with total planetary population.

You realize you just explained how things worked in MoO2, more or less? 

Would love two see this actually seen in the game distinctly instead of imaging civil and military populations.

We have defense improvements and population and this problem with sending billions in invasions. So with a bit of reworking why not actually have two populations military and civil. The military population would only be taken for invasions and only your military population defends the planet...or not depending if people think its a good idea.

End result being that the two would finally be in the game separately and people would be happy that's long time dream and true in the form of all mighty DLC.

DARCA

Quoting aerowreck, reply 3

You realize you just explained how things worked in MoO2, more or less? 

I never played any MOO game (shame on me ;))

Because when I conquer a Yor planet they can suddenly give birth and don't have to build new ones anymore. That being said, Paul mentioned on a dev stream once that they are looking into allowing you to have individual planets with multiple races living on them.

Despite the suggestions of the population growth branch of the tech tree, the game's population growth behaves nothing at all like biological population growth. The expected growth per time period of an animal population is

P*(b*H(Z) - d) + I(E)

where P is the current local population, b is an expected birth rate per some number of people per time period, H(Z) is a limiting function which modifies the population growth based upon the resource availability vector Z (which includes food availability and population pressure), d is an expected death rate per some number of people per time period, and I(E) is an immigration term dependent upon the vector E which includes factors such as total empire (or arguably galaxy) population, immigration and internal migration controls in the empire, immigration controls at the planet, desirability of the planet, pressures pushing people to depart other worlds, et cetera.

Instead, we have a population growth which is a constant 0.1 per turn, plus some modifiers. The names of the growth-boosting things may suggest that population growth is a result of biological functions, but the actual behavior of the numbers suggests otherwise.

Population growth, even for factions which supposedly have populations which grow by sexual reproduction, does not behave like a biological process. It does behave similarly to an enrollment (or recruitment) program which is provided with a constant amount of resources over the course of the game, with some modification for the attractiveness of the location (i.e. quality of the local medical and recreational facilities, etc) and local popularity of the government. It's not even like it's difficult or time-consuming to use something similar to a natural population growth model if you wanted population growth to reflect birth rates; the very basic model P(T+1) = P(T) * (b + 1) adds at most one multiplication to the current model of P(T+1) = P(T) + c, which should make rather little difference in computation time.

Ya, I know. The point still stands that, as far as the game is concerned, my Yor are transformed into my non-synthetic race when I take over one of their worlds. 

If you accept, as you claim you have, that the population growth is not in any sensible manner a function of biological reproduction, then to use that population growth function as the justification for the claim that a planet full of Yor becomes a planet full of humans upon conquest simply because the population growth goes from the on-demand set growth of the Yor populations to the population growth function used for biological populations is nonsensical.

If my empire's original species is not synthetic, then any colony of mine will have a population growth is 0.1 per turn with some modifiers, regardless of initial population at the colony, regardless of empire-wide population, and regardless of the population type which was presumably present upon the planet when I claimed it. In 50 turns of time (just under a year), I will have gained 5 additional population whether I started with 0.5 population or 5 population or 500 population. It makes no sense whatsoever to use a population growth rate which is so disconnected from the actual population present to infer information about the type of population which is present. The game mechanics are such that if you have a planet with a population of 0 and your empire is not set to be synthetic, then that planet will grow at a rate of 0.1 population per turn before modifiers (none of which include, for example, a -100% growth because there aren't any people here capable of reproducing). In what way does this differ from a planet with 5 synthetic population and 0 biological population growing at a rate of 0.1 population per turn before modifiers?

Ok dude, this has nothing to do with any game values or modifiers. I was using it as an example of why the Yor aren't Yor anymore when you conquer their planet. Growth rates have nothing to do with this. This is currently a problem with the flavour of the game, that is being worked on.