WPA2 is just a commercial name for a complete implementation of the 802.11i specification (WPA implemented only a part of it as a temporary measure against WEP weakness).
802.11i is an amendment to the original 802.11 specification, which means that it replaced several part from it, the original content becoming deprecated and a new revision of the 802.11 being edited.
More specifically, 802.11i introduces the concept of Robust Security Network Association (RSNA), and distinguishes between pre-RSNA security algorithms (WEP and 802.11 entity association) and RSNA security algorithms (the more secured algorithms allowed by WPA2).
Your hardware and software may offer pre-RSNA and RSNA security, usually as drop down menu allowing to select either WEP, WPA or WPA2. Your configuration here will define which algorithm you use, but at a given time you will use only one of them, they are not cumulative and will not be used at the same time.
For more information, 802.11i amendment can be found here (as per the current subject you directly jump to the "Security" chapter), and all successive amendments have been merged in the reference 802.11 specification (including deprecation of TKIP, which after all was just a temporary solution designed for WPA).