We live in a world of standardization. This means that we build components, parts, etc in accordance to some defined methodology or standard.
This standardization transcends the IT world and it is seen is virtually every aspect of our life. For example, a household light bulb is built to a standard so that it will work in a light bulb socket that meets its standard. This standardization permits vendor interoperability (several makers can, for example make a light bulb to the specific standard, and all will function in the light socket made by several different light socket makers).
For standardization to work, the standard has to be properly written and identified and any revisions also need to be written and identified. Usually a standard initially comes out as version 1.0 after all preliminary and draft standards have been reviewed and accepted. You refer to the specific standard as "XYZ standard 1.0" to clearly identify it. As revisions are approved the version number changes and this is how you specify the standard the specific parts meet.
Motherboard makers construct their boards to comply with specific standards so that other components which meet the specific standard will work together. The PCI 2.2 is a standard for the PCI port. If your graphic card meets PCI 2.2 standard it will work. I am not certain but often a current standard will also work with older standards (e.g. PCI 2.1 and 2.0 cards may well work in a PCI 2.2 socket but I do not know for sure this is the case; you can validate this for yourself and you should do that).
You can tell which standard a graphic card meets by reviewing the technical literature.