do I need install ethereum package?

do I need install ethereum package?

I am a beginner and got confused. According to some online tutorial, I need to install “ethereum” and “geth” package in my linux (ubuntu) first before I run any mining program such as cgminer. However, it seems without the two packages the mining program runs fine (I already have a public address). So what exactly are the “ethereum” and “geth” packages for? Do I need them?