6.05 Protists: A Wildly Diverse Kingdom

Welcome to the activity room. Not quite what you'd expect at a Dude Ranch, I know, but when you live on and work a real ranch, all aspects of the ranch are important. So we monitor our water very carefully! The spring-fed pond, where you just collected your water sample, is one of the main sources of water for our livestock. We pump the water from the pond right into the barn and send it through a simple filtration system, and it goes right to the animals.

If the water is clean, and the pond ecosystem is healthy, we'll expect to see certain protists represented in the organisms we observe. If the water is not clean, we'd find another set of organisms. We call these groups of protists indicator organisms because they "indicate" the ecological health of the water ecosystem we are observing.

First, let's watch a video clip to become a bit more familiar with the organisms in this kingdom. While watching, make sure to take note of the general ways these organisms are similar and different.

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Roll your mouse over the images below to identify what you're finding in your samples.

There are thousands of different kinds of protists. Many of these microscopic creatures live in pond water. The ones you're seeing are pretty representative of those found in a healthy pond.

Hundreds can be seen in one drop of water. So, now we know that these organisms can be environmental indicators. Take some time now to look more closely at their characteristics.

Fast Facts about Protists

• The Protist Kingdom is very diverse, meaning it contains many different kinds of organisms.
• All protists have eukaryote-type cells. Remember, these are cells with a membrane-bound nucleus and many membrane-bound organelles.
• Some protists are beneficial and some are harmful to humans.
• There are three basic types of protists:
       1. Animal-like protist (all single-celled, heterotrophs)
       2. Plant-like protist (some single celled; some multi-celled, autotrophs)
       3. Fungus-like protist (all multi-celled, heterotrophs)
• Most protist are unicellular, but some are multicellular.
• Protists can be autotrophs or heterotrophs.
• They can be found in fresh water, salt water, soil, and even living in other organisms.

Photo Moment

In addition to the protists you observed in your pond water, here are a few more sample images (don't forget to roll your mouse over them). Because most protists are quite tiny, we must use a microscope to see most of them. However, as you can see in these images, some are quite large and are multicellular. Notice that all the protists seen on this page have very unique shapes, but their designs are all special to meet their environments head on.

Well, you should have a pretty good handle on the organisms in the Protist Kingdom.

Head over to the Travel Log to complete this activity.