Thomas Sobat, PIE Fellow, Biology Department, Ball State University, Muncie, Indiana 47306
Standards Addressed
6.4.1 Explain that one of the most general distinctions among organisms is between green plants, which use sunlight to make their own food, and animals, which consume energyrich foods.
6.4.2 Give examples of organisms that cannot be neatly classified as either plants or animals, such as fungi and bacteria.
6.4.4
Investigate and explain that all living things are composed of cells whose details are usually visible only through a microscope.
6.4.9 Recognize and explain that two types of organisms may interact in a competitive or cooperative relationship, such as producer*/consumer*, predator*/prey*, or parasite*/host*.
Objectives
Participants will:
Refresh microscope knowledge.
Be able to distinguish between Algae and Protozoa
Be able to distinguish between flagellate, ciliate and sarcodine protozoans.
Materials
Cultured examples of 6-8 protists (one should be algal)
Microscopes 6-8
Pond or aquarium water
Blank microscope slides
Coverslips
Protoslow
Eyedroppers

Introduction
The differences that we see between plants and animals: autotrophs (make their own energy) versus heterotrophs (obtain energy from outside source), cells containing cell walls versus no cell wall and sessile verses mobile can also be seen in the plant animal precursors found in the kingdom Protista. The Algae (plant-like protists) and Protozoa
(animal-like protists) are examples of organisms that are microscopic and single celled.
The Algae are single cellular autotrophs that create their energy using chloroplasts that utilize carbon dioxide, water and the suns energy to produce simple sugars. Within this diverse group of organisms there are several divisions that divide the algae by the types of pigments they posses and cell structure. The Divisions (division is analogous to phylum; Botanists prefer this nomenclature) of Algae that are protists include the Green
Algae (Chlorophyta), the Golden-Brown Algae (Chrysophyta), the Diatoms
(Bacilariophyta), the Red Algae (Rhodophyta), and the Brown algae (Phaeophyta). With a few exceptions all are sessile (they do not move), and those that are mobile share characteristics with the animal-like protozoans.
The protozoans are single celled heterotrophs that obtain their energy by feeding on other protozoans, algae and detritus (dead or dying organic material). These organisms can be divided into phyla by their modes of locomotion; there are those that move using cilia
(small hair like structures that beat forming currents around the organism), flagella (a single or double tail that whip(s) about causing the organism to move forward, backward or to the side) and pseudopodia (movement through the extension of the cell membrane; amoeboid movement).
The ciliates are a group of organisms that use cilia (a short hair-like organelle) to move about or create currents that draw food in. Those ciliates that utilize their cilia for locomotion typically have the short hair-like organelles covering all or most of the external surface of the cell. The cilia beat creating a continuous current that the organism uses to move along through an aqueous medium. When using the cilia to collect food the cilia are centralized around an “oral” opening. There are many organisms that fall somewhere between the two having cilia covering part of the body with a high concentration around an area used for bringing food into the cell.
Flagellates are those single-celled organisms that utilize flagella for locomotion. Flagella are organelles with similar basal structure to the cilia, but differ in appearance by being long; sometimes as long or longer then the organism itself. Many of these organisms have two flagella, and may use one for lateral movement and the other for forward movement.
Organisms that are classified as sarcodines utilize pseudopodia, or cytoplasmic streaming to move from one location to the next. The cell membrane stretches in the direction that the organism is moving, and the cytoplasm follows the membrane. Pseudopodia (“false

foot”) has been more then adequate for this group of organisms, this form of locomotion has persisted for more then five hundred million years.
Procedures
1.
As participants are introduced to these procedures it should be mentioned that there is a course and fine focus on the microscopes, and that the course should never be used under the high power objective. Have several microscopes (6-8) set up as stations around the room, each should have a slide (Carolina Biological demo tubes work best for this) with an example of a protist. Have one specimen be algal to show differences between protozoans (animal-like) and algae (plantlike). The remaining specimens should be examples of the three groups discussed above.
2.
Each person should take note, perhaps draw the specimens, and be prepared to look at mixed cultures and distinguish between Algae, ciliates, flagellates and sarcodines.
3.
Have participants make wet mount slides from pond water, and try to identify those organisms found on their slides. It may be that those making slides need a review, or even first time instruction on making wet mounts.