Protists: Paramecium, Amoebas, Algae, Diatoms, Euglena, and Others
Learning About Protists
Protists are organisms in the kingdom Protista. The kingdom Protista is a highly diverse kingdom! The kingdom Protista is made up of organisms that didn't seem to fit into any other kingdom. Some examples of protists are paramecium, amoebas, euglenas, stentors, diatoms, dinoflagellates, and algae. On this page, I'll tell you a little bit about the characteristics of various protists, as well as show you what they look like in photos and youtubes.
This is a very short movie about protists.
Characteristics of Protists - Most protists are microscopic unicellular organisms.
Protists are a very diverse group. Many of them are in the Protista Kingdom simply because the wouldn't fit into any other kingdom! They are not plants, animals, or fungi.
- Unicellular or Multicellular? - Most are unicellular (have only one cell), but not all are. Kelp, for example, is a protist that is multicellular.
- Prokaryotes or Eukaryotes? - All Protists are euaryotes, which means they have a nucleus. In fact, protists are the first eukaryotes!
- Reproduction - Many reproduce by binary fission, which means splitting in two. Yet others reproduce by gametes (sexual reproduction.) Some protists have complex life cycles.
- Autotrophic or Heterotrophic? - Some protists engage in photosynthesis (like plants), others eat food they find (like animals), while others just absorb their food (like fungi).
- Locomotion - How do Protists get around? Some use flagella (a whip-like tail) or cilia (short hairs) to help them move. Amoebas use pseudopodia, which are extensions of their cytoplasm.
- Location - Most protists live in water, damp soil, sand, moist leaf litter, and other damp or wet locations.
- Parasites? - Some protists are parasites.
- Mechanisms for Monitoring or Being Aware of What's In Their Environment - Many protists do have mechanisms that help them be aware of their surroundings. Eyespots that can pick up the intensity of light are one of these mechanisms.
Here are some of the many types of Protists.
I've identified three of the protists in the protists collage above. If anyone knows what the other two types of protists are, please let me know so I can include their names as well!
Amoebas - Kingdom Protista, Phylum Rhizopoda
Amoebas are a type of Protist. Amoebas do not have cell walls, so they are very flexible. Amoebas move by using extensions of their cytoplasm which are called pseudopodia. These pseudopodia bulge out and anchor to another surface. The cytoplasm then flows into the extension.
To eat, amoeba surround bits of food.
Amoebas live in both fresh and salt water, as well as soil.
Amoebas reproduce by binary fission.
Here is an animation of binary fission.
An Amoeba in Action - Moving and Eating
Giant Amoebas can grow up to 5 mm long. Giant Amoebas in both the Chaos Genus and the Pelomyxa Genus have many nuclei, unlike smaller amoebas that have only one nucleus.
Forams - Kingdom Protista, Phylum Foraminifera
Forams are a type of Protist.
Forams are snail like animals and have long, thin "legs" of cytoplasm that stick out of their shells. These "legs" help them swim as well as catch food.
Forams have porous shells which are called tests. The shells are usually arranged in a spiral shape. The shells contain calcium carbonate and have accumulated on the ocean floors for millions of years, forming limestone.
Forams in action
Algae - Kingdom Protista, Phyla Chlorophyta (Green Algae), Rhodophyta (Red Algae), or Phaeophyta (Brown Algae)
Algae are a type of protist.
Algae engage in photosynthesis, like plants. Green algae, red algae, and brown algae have different photosynthetic pigments. One type of brown algae, Kelp, is one of the largest organisms on earth, reaching house size proportions at times. You can read more about Giant Kelp in the next section!
Giant Kelp - The "Trees" of the Ocean!
Giant Kelp is a type of protist too!
Giant Kelp grow in forests in the ocean. Some types of kelp can grow as fast as one half of a meter every day, eventually reaching 30 to 80 meters in height!
Kelp produces methane as it decays. In addition, kelp's sugars can be converted to ethanol. For these reasons, kelp may one day be used as a source of renewable energy for humans.
Although kelp resembles plants, kelp are not actually plants. Instead of roots, kelp has holdfasts which grip onto rocky substrates and hold the kelp in place. Unlike roots, holdfasts do not extend down into the substrate, but only anchor the kelp to it. Holdfasts also do not take in nutrients. The "leaves" of many types of kelp are called blades.
Kelp has bladders, called pneumatocysts, which are filled with a gas. These gas bladders help the upper portions of the kelp float near the surface. Giant kelp have a pneumatocyst at the base of every blade, but bull kelp has only one for several blades. .
Kingdom Protista, Phylum Chrysophyta
There are many species of Diatoms.
Diatoms are protists with double shells made out of silica. The shells of diatoms form diatomaceous earth which is used by people to control pests, add sparkle to road paint, and as an abrasive.
Diatoms engage in photosynthesis.
Diatoms have either radial symmetry (like a wheel) or bilateral symmetry (like a person's body where the right side matches the left).
Diatoms move by gliding, aided by chemicals they secrete through their shells.
Diatoms have an interesting method of reproducing. They separate the two halves of their shells and then each half regrows another half. One of the results of this method of reproduction is that the diatoms become smaller. Thus, when one becomes too small, it leaves it's shell, grows in size, and then grows a new shell.
Diatoms In Action:
Dinoflagellates - Kingdom Protista, Phylum Dinoflagellata
Dinflagellates are protists.
Most Dinoflagellates have two flagella. One encircles the body and the other runs perpendicular to the body. These flagella allow dinoflagellates to spin through the water.
Dinoflagellates have a cellulose coat which is often covered in silica. This gives dinoflagellates unique shapes!
Dinoflagellates can be autotrophic, heterotrophic, or both.
Dinoflagellates are often found in marine water, and are part of the plankton.
Dinoflagellates in action
Euglena - Kingdom Protista, Phylum Euglenophyta
Guess what?! Euglena are protists too.
Euglenoids also have two flagella. They also have an eye spot which helps them see light. Some Euglena are autotrophic while other types of Euglena are hetertophic.
Kingdom Protista, Phylum Kinetoplastida
(Some taxonomists classify them in the Euglenophyta Phylum instead)
Kinetoplastids have a DNA containing particle within their mitochondrian. This particle is called a kinetoplast. They also have at least one flagellum. Kinetoplastids are heterotrophic. Some Kinetoplastids cause disease in humans and other animals.
Cilates - Kingdom Protista, Phylum Ciliophora
Cilates are protists that get their names from their cilia, short hairs which help them move. Cilates are heterotrophs and do not engage in photosynthesis. Cilates have flexible bodies that can squeeze around or through other things.
Most Cilates have two nuclei: the micronucleus and the macronucleous.
Parameciums are one type of Cilate.
Cell structure of an ciliophora:
Cilates in action
Paramecium in action
Cellular Slime Molds
The protists called cellular slime molds are a group of amoebas that have come together during times of stress. They form colonies called slugs. Each slug forms a base, a stalk and a spore-forming tip. When the spores are released, each one becomes an amoeba. Watch this video to find out more about slime molds!
Cellular Slime Molds
Plasmodial Slime Molds - "Oozing slime"
Plasmodial Slime Molds are a collection of organisms that stream along as a plasmodium. As they stream, they engulf bacteria and other things they encounter. Plasmodial Slime Molds have many nuclei which are not separated by cell walls.
If a plasmodial slime mold begins to get too dry or hungry, it divides into smaller mounds which produce stalks topped with spore containing capsules. These spores eventually germinate into haploid cells (haploid cells contain half of the number of chromosomes as the adult of that species.) When two haploid cells get together, they create a diploid zygote. These zygotes undergo mitosis and become a new plasmodial slme mold.
Plasmodial Slime Molds
Oomycetes - Water Molds, White Rusts, Downy Mildews
(A) Sporangia, (B) Zoospores, (C) Chlamydospores, (D) Oospores.
Oomycetes have two flagella. One of these points forward and the other points backward.
Some types of oomycetes cause disease in plants. The potato blight in Ireland was called by the oomycete Phytophthora infestans.
Online Protists Flashcards and Games
- Protists Flash Cards and Games
Are you preparing for a tests on protists? On this website, you'll find some flash cards to help you study the different types of protists. There are also some free protists games available on this site!
Diversity and Characterstics of Protists - Paul Anderson (Bozemanbiology) talks about protists and their diversity.
Observing live protists is a wonderful way to learn more about them!
To observe live protists, you'll need a microscope and some slides. Having a few clean pipets (very inexpensive to buy) is also helpful. You can obtain samples of paramecium, amoebas, euglenas, etc, from Carolina Biological Supply and/or you can collect pond water. Our homeschool co-op did both. We had the best results with seeing the euglenas from Carolina Biological Supply! They were everywhere, swimming all around! There was no way to miss seeing them in the microscope!
Yet it was also fascinating to see what organisms could be found in water from a nearby pond!
Here are some activities (and tips) you may want to try.
Protists Slides - from Carolina Biological Supply
Although it's lots of fun (as well as educational!) to watch live protists swim around, it can be difficult to find some types in the microscope, and others won't hold still long enough for you to study them. You won't be able to watch live protists swim around via these slides, but you will be able to examine the physical structure of their bodies.
Although it's lots of fun to watch live protists (from Carolina Biological Supply, other companies or pond water) swim around, it can be difficult to find some types in the microscope, and others won't hold still long enough for you to study them. You won't be able to watch live protists swim around via these slides, but you will be able to examine the physical structure of their bodies.
For more info about Protists
- Kingdom Protista
For more information about protists, visit Kingdom Protista. In addition to information, you'll find great pictures as well as coloring sheets.