upgrading ubuntu

[MICHAEL WEAVER]

I have still a lot to learn about Linux and Ubuntu but is there a 
difference between apt-get upgrade and apt-get dist upgrade?
Is the difference between the first and second one upgrade on its own 
upgrades the security of the version of Ubuntu you are using and dist 
upgrade take you from the version of Ubuntu you have ie Edgy to the next 
version, Feisty?