1. Biology 1110 Principles of Biology
Biology 1110 Laboratory
Laboratory # 8
Kingdom Protista – The Protozoans
Support/Review Materials
All of the micrographs in this presentation were photographed in the MnWest Biology laboratory unless otherwise noted.
The microscope symbol that you see indicates a change in microscope power. A left mouse click on the microscope most often increases the viewing magnification. Give it a try.

2. Kingdom Protista .
Kingdom Protista consists of unicellular, multicellular, and colonial eukaryotes, that are in many ways, unlike animals, plants, or fungi (the other eukaryotes).
All protists require some sort of aquatic environment. Protists are found in fresh water and marine environments.
Ecological significance: The protists can exist in great numbers in aquatic systems and are an important part of the plankton. The plankton forms the base of aquatic food chains.
Some protozoans are important decomposers in living systems.

3. Kingdom Protista
The plant-like protists are the algae. The algae are autotrophic (specifically photosynthetic) and range from single-celled species and others common in local waters, to the giant multicellular algae of the sea. In this presentation we are studying the animal-like protists, known as the protozoans. Like the animals, the protozoans are heterotrophic. Some protozoans, such as the amoebas and paramecia are known to us, if only in name. The majority of protozoans are free-living, contributing to the living system, and causing no harm to other living things. Some protozoans, however, are disease-causing to humans and other species.

4. Some Human Diseases Caused by Protozoans
Disease Causative Agent Motion by Transmission
Amoebiasis Entamoeba histolytica Pseudopodia water, food
Giardiasis Giardia lamblia Flagella water, contact
Trichomoniasis Trichomonas vaginalis Flagella sexual, contact
African Sleeping
Sickness Trypanosoma brucei Flagella Tsetse fly
Balantidiasis Balantidium coli Cilia Food, water
Toxoplasmosis Toxoplasma gondii NA Domestic cats, food
Malaria Plasmodium sp NA Mosquito (Anopheles)

5. Protozoan Classification
Kingdom Protista
Subkingdom Protozoa
Phylum Sarcomastigophora Ciliophora
Subphylum Mastigophora Sarcodina
Genus Euglena Amoeba Paramecium
species Euglena sp Amoeba proteus Paramecium caudatum

6. Representative Protozoans
Although it is changing, traditional protozoans classification has been according to mode of locomotion.
In this exercise we will look at a protozoan that moves via ameoboid motion, a flagellated protozoan and a ciliated protozoan.
Often, the common name for protozoans is the name of the Genus. Check it out Common names we use will be amoeba, euglena, and paramecia.
Micrographs of living and stained specimens will be utilized in our study.

7. Representative Protozoans
Euglena sp.
Amoeba proteus
Paramecium caudatum

8. Amoeba Organelles/structures to identify. Nucleus
In the listing and on the diagram you will find the structures/organelles we will be observing in the micrographs of stained and living amoebas.
Clicking the forward button will take you to the appropriate micrograph.
Clicking the return button will bring you back to the listing.
Organelles/structures to identify.
Nucleus
Plasmalemma (cell membrane)
Ectoplasm
Endoplasm
Pseudopodia
Food vacuole
Contractile vacuole

9. The Amoeba - Nucleus
Amoeba proteus is the particular species of study for preserved, stained specimens and most living specimens. The common name is amoeba.
As is the case in all eukaryotic cells, the nucleus contains most of the cell’s DNA and is the control center for the cell.
Living Amoeba proteus
Stained Amoeba proteus
Nucleus

10. The Amoeba – Plamalemma, Ectoplasm, and Endoplasm
The plasmalemma is the outer limiting cell membrane.
The ectoplasm is a layer of relatively clear cytoplasm immediately inside the plasmalemma. The ectoplasm is important in movement and feeding.
The abundant endoplasm is the more fluid, granular appearing cytoplasm. The endoplasm contains the majority of the cell organelles.
Living Amoeba proteus
Stained Amoeba proteus
Plasmalemma
Ectoplasm
Endoplasm

11. The Amoeba - Pseudopodia
Pseudopodia are the locomotor organelles for amoebas. The term pseudopodium translates to mean false foot.
As the protoplasm flows, pseudopodia are formed and the amoeba moves in that direction. This locomotion is called amoeboid motion.
Stained Amoeba proteus
Living Amoeba proteus
Pseudopodia

12. The Amoeba – Food Vacuoles
Amoebas extend pseudopodia around their food and engulf the material through the process of phagocytosis. This process results in membranous food vacuoles being released to the inside of the cell.
Living Amoeba proteus
Stained Amoeba proteus
Food Vacuoles
Food Vacuoles

13. The Amoeba - Contractile vacuoles
Because protozoans live in fresh water, water continuously enters the cell. To prevent the protozoan from swelling and bursting , contractile vacuoles collect water and pump it to the outside.
Living Amoeba proteus
Stained Amoeba proteus
Contractile vacuole
Contractile vacuole

14. Euglena sp.
In the listing and on the diagram you will find the structures/organelles we will be observing in the micrographs of stained and living amoebas.
Clicking the forward button will take you to the appropriate micrograph.
Clicking the return button will bring you back to the listing.
Organelles/structures to identify Flagellum Chloroplasts Nucleus Stigma Cytostome Contractile vacuole Pellicle

15. Euglena sp. - Flagellum
The locomotor organelle for the euglenoids is a single whip-like flagellum.
This group of protozoans are referred to as the flagellates.
Living Euglenoid
Preserved Euglena sp.
Flagellum
Flagellum

16. Euglena sp. - Chloroplasts
Euglenoids, like most animals and other protozoans, move about their environment and consume food. In addition to this heterotrophic lifestyle, euglenoids contain numerous chloroplasts. Like green plants euglenoids are capable of photosynthesis. They are heterotrophic and autotrophic.
The green photosynthetic pigment chlorophyll gives living Euglena a green coloration.
Living Euglenoid
Preserved Euglena sp.
Chloroplasts
Chloroplasts

17. Euglena sp. - Nucleus The Nucleus is the control center of the cell.
It contains the great majority of the cell’s DNA.
Nuclear material stains deeply making it easily identifiable.
Preserved Euglena sp.
nucleus

18. Euglena sp. - Stigma
Most euglenoids are quite small and as a consequence we use the diagram to assist in our learning.
The stigma is a light sensitive structure (primitive eye). This structure proves useful for a mobile, photosynthetic organism.
Living Euglenoid
Stigma

19. Euglena sp. – cytostome, contractile vacuoles, and pellicle
The cytostome is a an opening used in feeding (primitive mouth).
Contractile vacuoles pump water to the outside as was seen in our study of Amoebas.
Living Euglenoid
Cytostome location
Next protozoan
Contractile vacuole
The pellicle is a membrane outside the cell membrane that provide support and flexibility.

20. Paramecium caudatum
Like other ciliates, paramecia move very efficiently by using the coordinated action of cilia. Paramecium caudatum is a fairly large protozoan and we will study micrographs of both living and preserved specimens.
Organelles to be identified
Cilia
Macronucleus & micronucleus
Contractile vacuole
Oral groove
Food vacuole
Peliicle, ectoplasm, endoplasm

21. Paramecium caudatum - Cilia
Often Paramecium caudatum is the ciliate of choice for study. As you can see in the micrographs below, the cell is covered with many cilia. The coordinated action of the cilia propel the organism and assist in food consumption.
Preserved Paramecium
Living Paramecium
Cilia
Cilia

22. Paramecium caudatum – Macronucleus & Micronucleus
One way in which ciliates differ from other protozoans is in having two kinds of nuclei. The large macronucleus is involved in regulating growth and metabolism. The small micronucleus is involved in reproduction and genetic recombination.
Preserved Paramecium
Macronucleus
Micronucleus

23. Paramecium caudatum – Contractile Vacuoles
Water continually moves into single-celled protozoans. In order to maintain water balance, excess water must be collected and pumped to the exterior. Contractile vacuoles perform this function.
Living Paramecium
Preserved Paramecium
Contractile vacuoles
Contractile vacuoles
Lets take a closer look

24. Paramecium caudatum - Contractile Vacuoles
In this high power micrograph, you can clearly see a contractile vacuole and the radiating canals that collect water and deliver it to the pumping structure.
The contractile vacuoles help maintain the osmotic balance between the inside of the cell and the cell’s environment.
Contractile vacuole
Radiating canals
Living Paramecium

25. Paramecium caudatum – Oral Groove and Food Vacuoles
The cilia within the oral groove sweep food material towards the cytostome and then into the cytopharynx. Material brought into the cell is packaged in a membranous food vacuole.
Living Paramecia
Oral Groove
Lets look on high power

26. Paramecium caudatum – Oral Groove and Food Vacuoles
The material is moved into the cell via the cytostome.
At the end of the cytopharynx food vacuoles are formed.
Other food vacuoles can be observed close by.
Living Paramecium
Forming Food vacuole
Cytopharynx
Anterior end

27. Paramecium caudatum – Pellicle, ectoplasm, and endoplasm.
As you watch living Paramecia, you see they have a definite, yet flexible shape. This due to the membranous pellicle (not visualized).
Like in the Amoeba, there is a thin, comparatively clear ectoplasm immediately inside the plasmalemma (cell membrane).
The more abundant granular endoplasm contains most of the cell’s organelles.
Living Paramecium
Endoplasm
Ectoplasm

28. Paramecium – Fission
Fission is a form of asexual (one parent) reproduction, where a single “mother” cell gives rise to two “daughter” cells. It is a continuous process, but often we speak in terms of stages.
Preserved Paramecium
In the early stages of fission the cell thickens, the micronucleus divides mitotically ( not observed), and the macronucleus elongates as it gets ready to divide.
Note the two cells pointed out in the micrograph.

29. Paramecium – Fission
As the process continues into and through the middle stages, the macronucleus divides. In latter stages cell division continues and then completes.
When the two “daughter “ cells separate, one must regenerate a new anterior end, the other must regenerate a new posterior end.
All micrographs are preserved, stained Paramecia
Fission complete

30. Paramecium – Conjugation
Most ciliates are capable of conducting a sexual process called conjugation.
This is not a reproductive process in that it starts with two and ends with two.
The two conjugating paramecia exchange genetic material so that they are different genetically when the process is complete.
Preserved Paramecium

31. Paramecium – Conjugation
Preserved Paramecium
Through the process of conjugation, genetic diversity is added to the ciliate population.
Conjugation is one form of genetic recombination. The diversity that results is particularly important to the asexually reproducing ciliates.

32. The End

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