There is a simple way to differentiate these products. For example:
Kaspersky Antivirus was developed to offer virus protection without any other modules.
Kaspersky Total Security contains the basic antivirus support plus a lot of other features meant to protect the PC against phising, powerful malware, password organizer, encryption, etc.
Basically, the Total Security is a full suite of modules and features designed to fully protect a PC.
More information about comparison can be found on the following page: http://www.kaspersky.com/compare