Biology Review

The other day I got into a disagreement with my wife about which of the Kingdoms (evolutionarily speaking) Saccharomyces cerevisae (baker's yeast) belonged to. I said "Fungi" and she said "Animals." Not surprisingly, I was right, but the point was is that I actually had to think about it for a sec.

A refresher on how life is broken up again. There's actually been a change since when I took high school biology with Mrs. Mendoza.

Traditionally, there were 5 kingdoms: Monera (bacteria), Protista (kind of a waste-basket category which includes simple animal-like and plant-like organisms which can be unicellular or multicellular--an example most people are familiar with is Paramecium), Plantae, Fungi (which does include yeast), and Animalia (that's us).

However, in the 1990s Carl Woese, who pioneered the analysis of ribosomal RNA as a means of showing more direct evolutionary relationships, noted that amongst the group "Monera", there were really two distinct groups, Eubacteria (the stuff we usually think of when we use the word "bacteria") and Archaebacteria (many of which have been in the scientific news in recent years due to their ability to live in "extreme conditions"). Woese proposed a "3 Domain" system which is used today. The 3 domains are the Archaebacteria, the Eubacteria, and the Eukaryotes. Amongst the Eukaryotes there are 4 Kingdoms (Protista, Plantae, Fungi, and Animalia).