Why did we have to become multicellular, anyway?

All things considered, we're pretty happy that life evolved into multicellular organisms — but what was the advantage to this shift? The answer may lie in brewer's yeast. Beyond just giving us the wonderful liquid that is beer, Saccharomyces cerevisiae has an interesting feature: it's far more efficient at certain… » 8/12/11 4:05pm 8/12/11 4:05pm