Biology I - Article Abstract 5 – 25
Points
INSTRUCTIONS: Read this article
and outline its important points by answering the questions at the bottom.
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Fungus Hunt by Emily Sohn, published in Science News for Kids, July 13th,
2005
There are
lots of ways to enjoy mushrooms. You can put portabellas on pizzas. You can
sauté shitakes with butter and garlic. You can hunt for morels in the woods. Or
you can study porcinis under a microscope. Scientists do all of these
things—and more. Mushrooms belong to a major group of organisms called fungi.
Not quite animals and not quite plants, fungi are turning out to be full of
mysteries and surprises.
Mushrooms pop
up in forests at certain times of year in various places all over the world and
then disappear completely without warning. Some are as big as a car. Others are
too small to see without a magnifier. Their colors range from bright orange to
purple to green. To add to the intrigue, it turns out that fungi are more
closely related to animals than they are to plants—even though they look more
like plants. Some types even seem to have ingredients that fight cancer, though
others can kill you.
"Once
you get to know them, they really become interesting," says mushroom
researcher David McLaughlin. More than just an ordinary mushroom lover,
McLaughlin is curator of fungi at the Bell Museum of Natural History in
Filaments and spores: A few basic traits tie all fungi
together. Most are made up of threadlike structures called filaments. They feed
on dead and dying organisms. To reproduce, they send out spores instead of
seeds. And the mushrooms that we see (and buy at the store) are just the fruits
of fungi. Most of a fungus stays hidden underground.
Across the
fungus kingdom, however, there's a large amount of variety—in looks, lifestyle,
and flavor. Some are delicious, while others are poisonous. Some grow on trees,
while most grow on the ground. To get a better idea of exactly what's out
there, McLaughlin and his coworkers are pulling together all the data published
about mushrooms over the last 40 years. They're also building large computer
databases to hold the information they collect. In the end, the researchers
hope to piece together a fungal family tree. The tree should help explain how
various types of fungi are related to each other and how different species
developed over the course of evolution. "We're trying to fill in holes in
the data so that people can understand how fungi evolved," McLaughlin
says.
There are
also practical reasons for creating a fungal family tree. Hundreds of kinds of
fungi cause diseases in people, including ringworm and athlete's foot. Some
5,000 types cause diseases in plants. Understanding which species are related
to one another allows researchers to predict which ones might cause diseases
and which ones might respond to certain treatments. Also, knowing how much
diversity is out there is the first step in knowing if and when certain species
start disappearing.
Diversity and
DNA
McLaughlin
uses various features of fungi to put them into categories, starting with the
shape, size, color, texture, smell, feel, habitat, and manner of growth of the
fungus itself and details of its cells, fruiting bodies, spores, hairs, and
other structures. Other researchers use modern advances in technology to
classify fungi. By comparing the genetic material DNA in two different species,
scientists can determine how closely related these species are.
In one recent
study, McLaughlin says, researchers took samples of soil from high elevations
in the Rocky Mountains. They found fungal DNA in the soil and were able to use
it to identify an entirely new type of fungus.
Taking a
closer look at mushrooms is also revealing how much more there is than meets
the eye in the wide world of fungi. "With new techniques, we've been able
to say, 'Oh my. We thought these were the same things. But now that we look
closer, we're able to say they're not the same thing,'" McLaughlin says.
"Everyone assumes that if it's shitake, it's a shitake. Well, a shitake is
not just one thing."
The porcini
group, too, appears now to include at least 35 species living across the
Northern Hemisphere, not one or two species as previously thought. That's
important because people have been using porcinis as medicine for thousands of
years. These mushrooms have also been getting attention lately for their
ability to destroy tumor cells. It's possible that not all types of porcinis
provide the same benefits.
Unfortunately,
most of the studies previously published about these mushrooms are useless now,
McLaughlin says, because the scientists didn't keep specimens of what they were
looking at. It's hard to tell exactly which particular type of mushroom they
were studying.
Creating a
new, large database will help researchers accurately classify the fungi they
are working on. Having such specific information about these fungi will make
their results more useful to other scientists. So, the fungi hunt continues,
whether it's to learn more about these fascinating organisms or simply to
identify something good to eat. Be careful, however. Don't eat any mushrooms
that you find in the woods without checking with a teacher, parent, or mushroom
expert first. Some mushrooms are poisonous enough to kill you.
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1. List the
title of the article, the author, where it was published, and the date it was
published.
2. What is
one kind of fungus that you can eat?
3. What are
the two ways that fungus reproduce, or grow and spread?
4. What do fungus eat?
5. What is
one disease that fungus causes in humans?
6. Can you
eat any mushroom you find in the forest? Why not?