Back

PROTOZOA
Lesson 1 - Page 1

Next 

light microscope

coverslips

slides

dropper

prepared slides of paramecium, amoeba, euglena, stenor, radiolarians

 

 

The Kingdom Protista are single-celled organisms that have a true nucleus (eukaryotic). Protista may be either autotrophic or heterotrophic. Movement by protists is dependent upon certain physical characteristics. Some protozoa have pseudopodia which can extend the cell membrane and push forward or surround a food particle, such as an amoeba does. A protist that possesses a single tail-like structure is called a flagellate. The flagellum will beat back and forth and propel the organism through the water, examples are trypanosome and trichosomes. Some Protozoa are covered with tiny hair-like structures called cilia which move back and forth quickly propelling the organisms through the water. A paramecium is an example of a ciliate. Some Protozoa have axopodia, or pencil-like structures, that help them to be planktonic or floaters in the water. Radiolaria are marine examples of protozoa containing this feature.

There are many debates about whether protozoa are all one-celled organisms or whether they are all one-celled organisms that are heterotrophs. Scientists who study these groups, debate on how to classify some of these organisms, like euglena and dinoflagellate. With more study these groups will be better understood.

Most protozoa are helpful in that they are important in lower levels of the food chain. They provide food for living things such as snails, clams, and sponges. Some protozoa are capable of causing diseases in humans and other animals. Some diseases caused by protozoa in humans are malaria, black fever, sleeping sickness, and some types of diarrhea.

Protista are single-celled organisms that have a true nucleus (eukaryotic). Protista may be either autotrophic or heterotrophic. Movement in protista is dependent upon certain physical characteristics. Some protozoa have pseudopodia which can extend its cell membrane and push itself forward or surround a food particle. A protozoa that possesses a single tail-like structure is called a flagellate. The flagella will beat back and forth and propel the organism through the water, examples are trypanosome and trichosomes. Protozoa that are covered with tiny hair-like structures called cilia move back and forth quickly propelling the organism through the water. Paramecium are examples of ciliates. Protozoa that have axopodia, or pencil like structures, help these protozoa to be planktonic or floaters in the water. Radiolaria are marine examples of protozoa containing this feature.

There are many debates about whether protozoa are all one celled organisms or whether they are all one celled organisms that are heterotrophs. Different textbooks will no doubt show this difference of opinion. Scientists who study these groups are not sure where they place some of these organisms, like euglenas, dinoflagellates, and many others. With more study the position of these groups will be understood more, but until then, give your students the sense that this is a not well understood portion of biology.

Most protozoa are helpful in that they are important in lower levels of the food chain. They provide food for living things such as snails, clams, sponges. Some protozoa are capable of causing diseases in humans and other animals. Some diseases caused by protozoa in humans are malaria, black fever, sleeping sickness, and some types of diarrhea.

Students will use the light microscope to look at prepared samples. Have them follow the lab procedures on their activity sheet. The first lab will consist of prepared samples and the second lab 9 will have students look at live materials.

PROBLEM: How can you distinguish different protozoa?

HYPOTHESIS: ___________________________________________________________________

MATERIALS: 5 prepared slides of different protozoa

EUGLENA AMOEBA STENTOR

 

 

 

 

RADIOLARIA PARAMECIUM

 

 

 

 

 

CONCLUSION: How can you distinguish among the different protozoa that you looked at in lab?

__________________________________________________________________________________________________________________________________________________________________

PROBLEM: Which protozoa live in pond water?

HYPOTHESIS: ___________________________________________________________________

MATERIALS: pond water, light microscope, microscope slide, coverglass

Using a light microscope, examine the pond water.

a. Make a slide of sample.

b. Examine each slide under low and high power of your microscope.

c. Draw the different type of protozoa that you see. Use the key provided to identify each critter.

CONCLUSION: How many different types of protozoa did you find? Were there any special ways to capture the most?___________________________________________________________________________________________________________________________________________________________________________________________________________________________________