Sometimes you get a process in your top listing, and you don't know what launched it. Normally you would have to launch ps and match up the PPID with another process's PID. The pstree utility will do this work for you, and draw the ps listing as a pretty tree.
For example, at startup time, init launches the WindowServer, which launches the dock:
-+- 00001 root /sbin/init[Lines trimmed to narrow the display width]
|--- 00041 root kextd
|--- 00075 ben /System/Library/Frameworks/ApplicationServices...
|-+- 00077 ben /System/Library/CoreServices/WindowServer
| |--- 00333 ben /System/Library/CoreServices/Dock.app...
| |--- 00334 ben /System/Library/CoreServices/SystemUIServer...
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020523205729998