Is it ever explained in universe how the three races can use the same resources?

Question

It is somewhat feasible to assume that Terrans and Protoss use the same Materials for building their stuff. But how do the Zerg fit into this? It seems strange to me that the Zerg use the very same resources that Terrans and Protoss.

I do not remember that there was ever a satisfactory explanation of this in game. I have to admit though that my last playthrough of Starcraft 1 has been several years ago, so I do not remember if it was mentioned there.

Answer 1

The starcraft I manual touches on this:

Resources

In order to build up your army, you will need to collect the raw materials necessary to develop and build your war machines. There are two types of resources. You will need to procure both in order to build your full complement of troops.

Mineral Deposits

The planets along the rim are often dotted with clusters of precious Mineral crystals. These Minerals are smelted down and used to create the armoured hulls of starships, vehicles and personal armour. Even the Zerg require Minerals to harden their carapaces and develop strong teeth and bones. The Mineral crystals take some time to gather, and only SCVs, Drones, and Probes have the necessary equipment to break off bits of the crystals and return them to the proper building.

Vespene Geysers

Vespene gas has an unusually high potential energy rating, and as such it is highly valued for use as a fuel in highperformance engines and energy reactors. The Zerg have adapted themselves to use raw Vespene as a source of nourishment to drive their greatly accelerated metabolisms. Even the Protoss require Vespene to work as a catalyst for their psi-driven machines. Geysers of this powerful green gas can be found on many planets along the Rim, and several space stations have been built over Vespene-rich asteroid belts. A refinery of some sort must be built over an active geyser to process and package the gas for its collection by the different species.

Answer 2

Not sure if it is explained in the game itself, but it is explained on the wiki, and they quote the SC1 game manual.

Vespene gas is also used by other races. The zerg have adapted themselves to use raw vespene as a source of nourishment to drive their greatly accelerated metabolisms, raw vespene exposure resulting in enhancement of the ultralisks physical capabilities. In contrast, the protoss use vespene as a catalyst for their psi-driven machines.

And Minerals :

Terrans and protoss melt these minerals down to create the armored hulls of starships, vehicles and personal armor. Even the zerg require minerals to harden their carapaces and develop strong teeth.

Sources: minerals and Vespene Gas

Answer 3

I have played all versions many times and have read many of the starcraft books, but I don't recall such an issue being addressed anywhere.

The obvious answer is that since they all play in the same map, so they should all use the same resources. That is, there is no option for the game designers to think otherwise.

Only thing one can do then is to try to justify this fact.

If you have played Wings of Liberty and have talked with Dr. Hansen after the Tosh missions, you would have heard her talk about the effects of those special gas and minerals that you collected and how they affect psychic abilities (or something along those lines).

I would say probably the use of the same materials by all three races is justified by two things.

1. They are the common widespread useful materials in the universe. They are in every planet and every world of the universe. Since all races expand over many planets, they would develop technology or evolve so that they use the most common material around.
2. If currently the crystal or gas are not as effective as those Tosh seeked, in the past they used to be and therefore they attracted the races for their properties.

I would expand the second reason a bit more based on the race. Before though, I'd like to remind you that the three races seem to be sharing psychic properties. (Wait, they call it psychic or psionic? Anyway, it's all the same). We know this because Sarah Kerrigan for example controls the zerg, Jake Ramsey had a protoss in his head (and that episode with other humans experience the Khala), and the overmind learned the location of Aiur when he touched Zeratul's mind when he killed a cerebrate.

• Terrans: Crystal and gas for terrans seem the easiest to explain. They use the crystal to extract minerals and they burn gas.
• Protoss: Due to the psychic powers of the crystal and gas (at least in the past), they embed them in their structures or armor to keep them powered up (spiritually).
• Zerg: Again, due to the psychic powers of the crystal and gas, they have evolved into extracting the energy from them to speed up their growth and connection to the overmind.

On the zerg, I didn't pay quite so much attention here, but I don't recall seeing the primal zerg (in hearth of the swarm) actually gather resources either, which could mean that their use of these resources started after they left the home planet, when they expanded to other planets and where bound to the overmind.