Three domains, or six reigns?

In the primary schools (or may be it was the secondary, I don't remember exactly), I was taught by my teacher that all living things belong to one of five different Reigns (or kingdoms - but without a king I guess). Animals, Plants, Fungi, Protists, Bacteria.


this is the oldest version with only three kingdom recognised at the time.

Bacteria are the oldest and the simplest, with the others being grouped under the collective label of Eucharyotes. I'm not going to dwelve in details here. check the wikipedia or your biology textbook for that.

Anyway, some time ago I came to know that in fact not all bacteria are born the same. Some of them, called Archeobacteria, do seems to be more rudimentary, yet they are though to have originated Eucharyotes as well.



the whole thing is quite confusing as other people say they are in fact unrelated, and they just sit on the same branch of the tree of life just because 'normal' bacteria are different from both of them.

If you feel like I've confused you, and would like to get clearer idea, here's where you should go. read the posts from the bottom up. cheers