Fungus-like Protists
Jessica Harwood
Douglas Wilkin, Ph.D.
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AUTHORS
Jessica Harwood
Douglas Wilkin, Ph.D.
EDITOR
Douglas Wilkin, Ph.D.
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Printed: February 10, 2015
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C HAPTER
Chapter 1. Fungus-like Protists
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Fungus-like Protists
• Describe features of the fungus-like protists.
• Distinguish slime molds from water molds.
What’s shrouding this dead insect?
The thin filaments growing out of this dead insect look a little like a fungus. Also this mystery organism, like a
fungus, is feeding on decaying matter. However, this is not a fungus. This organism is a type of fungus-like protist,
known as water mold.
Fungus-like Protists
Fungus-like protists share many features with fungi. Like fungi, they are heterotrophs, meaning they must obtain
food outside themselves. They also have cell walls and reproduce by forming spores, just like fungi. Fungus-like
protists usually do not move, but a few develop movement at some point in their lives. Two major types of funguslike protists are slime molds and water molds.
Slime Molds
Slime molds usually measure about one or two centimeters, but a few slime molds are as big as several meters. They
often have bright colors, such as a vibrant yellow ( Figure 1.1). Others are brown or white.
Stemonitis is a kind of slime mold which forms small brown bunches on the outside of rotting logs. Physarum
polycephalum lives inside rotting logs and is a gooey mesh of yellow "threads" that are several centimeters long.
Fuligo, sometimes called “vomit mold,” is a yellow slime mold found in decaying wood.
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FIGURE 1.1
An example of a slime mold.
Water Molds
Water molds mostly live in water or moist soil. They can be parasites of plants and animals, getting their nutrients
from these organisms and also from decaying organisms. They are a common problem for farmers since they cause
a variety of plant diseases. One of the most famous of these diseases was the fungus that caused the Irish potato
famine in the 1800s. At this time, potatoes were the main source of food for many of the Irish people. The failure of
the potato crop meant that many people in Ireland died of starvation or migrated to other countries.
Summary
• Slime molds are fungus-like protists that grow as slimy masses on decaying matter. They are commonly found
on items such as rotting logs.
• Water molds are fungus-like protists present in moist soil and surface water; they live as parasites or on
decaying organisms.
Explore More
Use the resources below to answer the questions that follow.
Explore More I
• The Blob: Slime Mold at http://herbarium.usu.edu/fungi/FunFacts/slimemold.htm .
1. Why are slime molds not classified as fungi?
2. What does a plasmodial slime mold eat?
3. What is different about the nucleus of the single cell of the plasmodial slime mold?
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Chapter 1. Fungus-like Protists
Explore More II
• John Bonner’s Slime Mold Movie at http://www.youtube.com/watch?v=bkVhLJLG7ug (1:42)
MEDIA
Click image to the left or use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/57455
1. What happens when you separate the cells of a slime mold?
2. Do you think this behavior represents intelligence? Why or why not?
3. Slime molds will form stalks with fruiting bodies.
a. What happens to the cells of the stalk?
b. What happens to the cells of the fruiting body?
Review
1. What are examples of fungus-like protists?
2. How do water molds get their nutrients?
References
1. National Park Service. Slime mold. . Public Domain
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