[Space] Interactions between species

[johndallman]

Originally Posted by Frost

. . . sapient life (with similar biochemistry) is relatively common.

There are several meaningful grades of "similar biochemistry":

1. We can breathe the same air. This might not be identical to anyone's home atmosphere, but it's compatible with the species of interest.
2. Same air, same water (nobody requires strange additives in the water).
3. Same air, water, and some of the same foods.
4. Same air, water and food, with nutritional supplements. Quite a lot of space opera can fit this, if you assume characters take their vitamin pills off-camera.
5. We're from essentially identical biospheres.

[Frost]

Originally Posted by johndallman

There are several meaningful grades of "similar biochemistry":

1. We can breathe the same air. This might not be identical to anyone's home atmosphere, but it's compatible with the species of interest.
2. Same air, same water (nobody requires strange additives in the water).
3. Same air, water, and some of the same foods.

As I say I am not sure of my species other than a version of one I have had lying around for a while I figure that similar is going to be somewhere between 2 and 3.

[Pursuivant]

Originally Posted by johndallman

There are several meaningful grades of "similar biochemistry":

Below "we can breathe the same air" there is also:

* We can survive in the same general types of atmospheres using highly-reliable environmental suits or similar technology (e.g., the Breen from Star Trek or the Illensans from the Sector General books).

It also covers species which can survive in an Earth-like environment with simple equipment like respirators or supplemental breathing gas generators.

As long as extremely reliable, portable, gravity control technology is available, this option also allows species from extremely high or low gravity environments to all happily play together.

At the other end of the scale, there's:

* Susceptible to the same diseases, poisons, etc.
* Can interbreed.

These options cover silliness like Star Trek humanoids being susceptible to alien viruses and being interfertile, despite billions of years of independent evolution.