A species
Baker's yeast
Saccharomyces cerevisiae
The single-celled fungus that makes bread rise.
You and the baker's yeast last shared an ancestor about 1.3 billion years ago (on 10 September, if life's history were one year).
Meet the single-celled fungus behind a lot of bread and beer. Baker's yeast is a distant relative of the fly agaric beside it on the tree, but it lives as just one small oval or round cell. Each cell is far too small to see without a microscope, at about one-tenth the width of a human hair.
As it feeds on sugar it makes tiny bubbles of gas and some alcohol. In bread dough the trapped bubbles make the mix rise and puff up, then baking sets them as air pockets. This same kind of yeast helps make many kinds of beer, wine and sake, with special types grown for each job.
In the wild this yeast lives on oak bark and nearby soil, as well as on ripe fruit and flowers, and is carried by wasps and flies. It mostly makes more of itself by budding, when a small round bud grows on the mother cell and then breaks away. One cell can quickly become millions in warm sugary food.
Helped win a Nobel Prize
Work on how its cells grow and divide helped earn a share of the 2001 Nobel Prize for finding key controls that tell cells when to divide.
Tough spores for hard times
When food runs out, some hungry cells can make four tough spores packed in a little sac.
Used for thousands of years
Chemical traces of fermented drinks in very old pots suggest people may already have been using this yeast by about 7000 BCE.