ONCE more, dear reader, it is our delight to discuss a column by the splendidly-evolved Olivia Judson — an evolutionary biologist and a research fellow in biology at Imperial College London. This article, part of Dr. Judson’s series in the New York Times, is titled: Bubbles, Bread and Beer. Here are some excerpts, with bold added by us:
Saccharomyces cerevisiae, also known as baker’s yeast, is one of the most useful beings known to humans. We rely on it for making bread and beer; but it is also a denizen of the laboratory, one of the most studied organisms on the planet. Which is why I’m nominating it for Life-form of the Month: June.
Yeast is a “being”? Okay, if Olivia says so. Let’s read on:
But what is it? Yeasts are fungi — so they are related to mushrooms. And fungi are, strangely, quite close relations of ours.
Hey — your Curmudgeon ain’t no kin to no yeast! We continue:
Or at least, they are more closely related to animals than they are to plants. Like animals, they digest their food — though fungi do it not by swallowing, but by releasing chemicals into the environment. The chemicals break down the food — like rotting wood — into smaller molecules, and the fungus then imports these smaller molecules into its cells.
Yuk! Let’s see what else we can learn:
Sometimes this takes on sinister dimensions. For example, if you are nematode worm crawling through the soil, you may get stuck in a sticky web. But in this web there is no spider. The web itself is alive: it is not made of silk, but of the filaments of a fungus. The web itself will digest you.
Come on, Olivia — you’re creeping us out! Give us something we can relate to:
Some species have huge numbers of sexes — the mushroom Schizophyllum commune is estimated to have as many as 20,000. (This doesn’t mean that 20,000 individuals must assemble for some sort of shroomed-out orgy; sexes are a set of genetic rules for which pairs of individuals can swap genes with each other. Members of the same sex do not swap genes.)
Gotta love Olivia, she always tells us about those juicy little details. Here’s more:
Further accomplishments: the first “tree” appears to have been a fungus of some sort — it lived in the Devonian period, around 400 million years ago — and sometimes stood as tall as nine meters (almost 30 feet). And although today’s fungi don’t stretch towards the skies, some of them are massive. Single individuals of the species Armillaria bulbosa have been estimated to cover 15 hectares (37 acres) and weigh 10,000 kilograms (22,000 pounds). Funky.
Bulbosa — it’s well named. One last excerpt:
[H]umans and yeast have many genes in common: about 60 percent of yeast genes are known to have human equivalents, and almost a quarter of human disease-causing genes have equivalents in yeast. Studying yeast genes thus gives us a window into what some of our most essential genes are doing. Indeed, suppose you create a yeast “knock out” — you remove one of the yeast genes. Often, this will have a clear and detrimental impact on how the organism grows. Now, replace the knocked-out gene with the human version — and like as not, you will have restored the yeast to its former frothy self.
We certainly hope the creationists don’t learn about that. It could be detrimental to their delicate hold on reality.
There’s plenty more yeasty information in Olivia’s column. Click over there and read it all. Time devoted to Olivia is always well spent.
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