following up on Darcie's post
The 5 kingdom phylogenetic (evolutionary history) system is outdated since Kingdom Monera and Kingdom Protista are polyphyletic, that is, they have grouped together organisms that are superficially similar (due to convergent evolution), but that don't share a most common ancestor. In other words, they look similar because they evolved similar methods of survival, but they're only distantly related. It's like saying that a shark and a dog are closely related because they are carnivores.
Kingdoms Protista and Monera used to be something like "trashcan" kingdoms, where you'd basically include in them what didn't fit into the other ones.
This phylosophy changed recently, and there's an ongoing effort to make an accurate phylogenetic tree of all the organisms on the planet. The problem is that there are so many different species of bacterias and protists that we might end up with 20 Kingdoms or more instead of 5. :S There's still a lot of controversy over all of this, but I think it's like arguing over how many angels can dance on the head of a pin. I'm certainly not gonna lose any sleep over it.
Just a though...
EDIT: Um, if I sound pompous, sorry about that. [img]http://www.**********.com/iB_html/non-cgi/emoticons/alien.gif[/img]