"Minute Life" Lab : Protozoa and Protists
Introduction
Protists are a varied group of eukaryotic organisms that can be unicellular or multicellular and heterotrophic or autotrophic. This is because within the Protist classification there is a unique group of organisms sharing ancestors with plants, animals, and fungi. In the first part of our lab we first took a look under the microscope at three protists: Amoeba, Paramecium, and Euglena. The amoeba viewed was from the phylum Plasmodroma and the family Amoebidae. We also viewed a paramecium from the phylum Ciliophora and family Parameciidae. Finally, the Euglena we observed were classified under phylum Euglenozoa and family Euglenaceae. Each protist we saw varied in its structure, habitat, nutritional mode and ecological importance. After examining these three protists we looked at a fourth kind, chlamydomonas. We noted the distinct characteristics of each.
Abstract
When we observed protists under the microscope marked differences were evident between different phylums. In our lab we observed four types of protists, Euglena, Paramecium, Amoeba, and Chlamydomonas. The slides viewed under the microscope showed four very distinct protists in terms of mobility, coloration, and structure. The results of our lab confirmed that although these organisms are similar in their cell type, they are different enough from each other to be classified under separate phylum.
Protists are a varied group of eukaryotic organisms that can be unicellular or multicellular and heterotrophic or autotrophic. This is because within the Protist classification there is a unique group of organisms sharing ancestors with plants, animals, and fungi. In the first part of our lab we first took a look under the microscope at three protists: Amoeba, Paramecium, and Euglena. The amoeba viewed was from the phylum Plasmodroma and the family Amoebidae. We also viewed a paramecium from the phylum Ciliophora and family Parameciidae. Finally, the Euglena we observed were classified under phylum Euglenozoa and family Euglenaceae. Each protist we saw varied in its structure, habitat, nutritional mode and ecological importance. After examining these three protists we looked at a fourth kind, chlamydomonas. We noted the distinct characteristics of each.
Abstract
When we observed protists under the microscope marked differences were evident between different phylums. In our lab we observed four types of protists, Euglena, Paramecium, Amoeba, and Chlamydomonas. The slides viewed under the microscope showed four very distinct protists in terms of mobility, coloration, and structure. The results of our lab confirmed that although these organisms are similar in their cell type, they are different enough from each other to be classified under separate phylum.
Procedure
Procedure One
We selected the following three protists during our lab. We made wet mounts and observed each under the microscope.
·Amoeba
·Paramecium
·Euglena
Wet Mounts:
In order to observe protists under the microscope we had to first create wet mounts, slides, that can be used to view them. The following is a procedure for creating wet mounts.
1. We gathered a glass slide and added a drop of proto-slow which was used to slow the movement of our protists.
2. Next we added a drop of the first protist using a plastic pipette.
3. We then added a drop of water to dilute the sample of the protist and mixed the contents of the slide with a toothpick.
4. Finally we added the plastic coverslip and were ready to view our protist.
5. We repeated this procedure for the Amoeba, Paramecium, and Euglena.
Background Information:
Phylum Chlorophyta (Green Algae – Ancestors to Land Plants)
Green algae are the most diverse and familiar algae in freshwater. However, a few genera live in salt-water. Although their name (Chlorophyta) means “green chlorophyll plants” (chloro +phyta), these algae are not classified as plants. Green algae are considered to be ancestral to land plants and share many characteristics with land plants, such as
·Chlorophyll a, which occurs in algae and green plants.
·Chlorophyll b, which occurs in land plants and in the green euglenoid algae.
·Starch as the carbohydrate storage material
·Cell walls made of cellulose
Procedure Two
Observing Chlamydomonas (dimple plates for this procedure)
1. First we observed a drop of water containing living Chlamydomonas under the microscope and noted the movement of the cells.
2. Since the movement of the chlamydomonas was too fast to view, we made a new preparation by placing one or two drops of methylcellulose on a slide and added a drop of water containing Chlamydomonas.
3. Then we mixed gently and added a coverslip.
4. Next we noted the stigma, which appeared as a reddish, light absorbing spot at the anterior end of the cell.
5. Lastly, we examined the prepared slides of Chlamydomonas.
Background information
– Chlamydomonas usually reproduces asexually via mitosis. Sexual Reproduction in Chlamydomonas is a response to unfavourable environmental conditions. For sexual reproduction, vegetative cells of Chlamydomonas undergo mitosis to produce gametes. The gametes fuse to form a diploid zygote, which is the resting stage of life cycle. In most species of Chlamydomonas, the gametes of two convenience, isogametes of Chlamydomonas are referred to as + or -. Gametes unite to form a diploid zygote.
Observing Syngamy
1. First we placed drops of + and – gametes of Chlamydomonas next to each other on a microscope slide. We were careful not to mix the two drops. At this point we did not add a coverslip.
2. We observed the drops through the low power objective of the microscope and then mixed the two drops of isogametes.
3. Finally, we switched to the high power objective and noted the clumping gametes. We then tried to locate cells that were paired or in the process of mitosis.
We selected the following three protists during our lab. We made wet mounts and observed each under the microscope.
·Amoeba
·Paramecium
·Euglena
Wet Mounts:
In order to observe protists under the microscope we had to first create wet mounts, slides, that can be used to view them. The following is a procedure for creating wet mounts.
1. We gathered a glass slide and added a drop of proto-slow which was used to slow the movement of our protists.
2. Next we added a drop of the first protist using a plastic pipette.
3. We then added a drop of water to dilute the sample of the protist and mixed the contents of the slide with a toothpick.
4. Finally we added the plastic coverslip and were ready to view our protist.
5. We repeated this procedure for the Amoeba, Paramecium, and Euglena.
Background Information:
Phylum Chlorophyta (Green Algae – Ancestors to Land Plants)
Green algae are the most diverse and familiar algae in freshwater. However, a few genera live in salt-water. Although their name (Chlorophyta) means “green chlorophyll plants” (chloro +phyta), these algae are not classified as plants. Green algae are considered to be ancestral to land plants and share many characteristics with land plants, such as
·Chlorophyll a, which occurs in algae and green plants.
·Chlorophyll b, which occurs in land plants and in the green euglenoid algae.
·Starch as the carbohydrate storage material
·Cell walls made of cellulose
Procedure Two
Observing Chlamydomonas (dimple plates for this procedure)
1. First we observed a drop of water containing living Chlamydomonas under the microscope and noted the movement of the cells.
2. Since the movement of the chlamydomonas was too fast to view, we made a new preparation by placing one or two drops of methylcellulose on a slide and added a drop of water containing Chlamydomonas.
3. Then we mixed gently and added a coverslip.
4. Next we noted the stigma, which appeared as a reddish, light absorbing spot at the anterior end of the cell.
5. Lastly, we examined the prepared slides of Chlamydomonas.
Background information
– Chlamydomonas usually reproduces asexually via mitosis. Sexual Reproduction in Chlamydomonas is a response to unfavourable environmental conditions. For sexual reproduction, vegetative cells of Chlamydomonas undergo mitosis to produce gametes. The gametes fuse to form a diploid zygote, which is the resting stage of life cycle. In most species of Chlamydomonas, the gametes of two convenience, isogametes of Chlamydomonas are referred to as + or -. Gametes unite to form a diploid zygote.
Observing Syngamy
1. First we placed drops of + and – gametes of Chlamydomonas next to each other on a microscope slide. We were careful not to mix the two drops. At this point we did not add a coverslip.
2. We observed the drops through the low power objective of the microscope and then mixed the two drops of isogametes.
3. Finally, we switched to the high power objective and noted the clumping gametes. We then tried to locate cells that were paired or in the process of mitosis.
Definitions
Structure of an amoeba: unicellular animal with pseudopods that lives in fresh or saltwater.
Pseudopodium: part of the amoeba used for locomotion.
Ectoplasm: vitreous superficial layer of an amoeba.
Endoplasm: central part of an amoeba.
Cell membrane: membrane covering an amoeba.
Contractile vacuole: cavity of the amoeba that is able to contract.
Food vacuole: cavity of the amoeba responsible for digestion.
Nucleus: central organelle for an amoeba.
Digestive vacuole: cavity of the amoeba responsible for digestion.
Structure of a paramecium: large ciliate protozoan that lives in stagnant freshwater.
Cilia: minuscule cilia that envelop the paramecium and are used for locomotion.
Contractile vacuole: cavity of the paramecium that is able to contract.
Food vacuole: cavity of the paramecium responsible for digestion.
Micronucleus: one of the less important central organelles of a paramecium.
Oral groove: canal of the paramecium used to ingest nutrients.
Gullet: cavity of the pharynx.
Ectoplasm: vitreous superficial layer of a paramecium.
Endoplasm: central part of a paramecium.
Large nucleus: the most important central organelle of a paramecium.
Canals of contractive vacuole: division of the contractile cavity of a paramecium.
Trochocyst: root of a vibrative cilium of a paramecium.Reservoir: part of a euglena used for storage.
Nucleus: central organelle of a euglena.
Contractile vacuole: cavity of the euglena that is able to contract.
Pellicle: membrane that envelops a euglena.
Chloroplast: organelle of the euglena responsible for photosynthesis.
Nucleolus: spherical body that contains the nucleus of a euglena.
Stigma: light-sensitive part of a euglena.
Flagellum: long, mobile filament used by the euglena for locomotion.
Pseudopodium: part of the amoeba used for locomotion.
Ectoplasm: vitreous superficial layer of an amoeba.
Endoplasm: central part of an amoeba.
Cell membrane: membrane covering an amoeba.
Contractile vacuole: cavity of the amoeba that is able to contract.
Food vacuole: cavity of the amoeba responsible for digestion.
Nucleus: central organelle for an amoeba.
Digestive vacuole: cavity of the amoeba responsible for digestion.
Structure of a paramecium: large ciliate protozoan that lives in stagnant freshwater.
Cilia: minuscule cilia that envelop the paramecium and are used for locomotion.
Contractile vacuole: cavity of the paramecium that is able to contract.
Food vacuole: cavity of the paramecium responsible for digestion.
Micronucleus: one of the less important central organelles of a paramecium.
Oral groove: canal of the paramecium used to ingest nutrients.
Gullet: cavity of the pharynx.
Ectoplasm: vitreous superficial layer of a paramecium.
Endoplasm: central part of a paramecium.
Large nucleus: the most important central organelle of a paramecium.
Canals of contractive vacuole: division of the contractile cavity of a paramecium.
Trochocyst: root of a vibrative cilium of a paramecium.Reservoir: part of a euglena used for storage.
Nucleus: central organelle of a euglena.
Contractile vacuole: cavity of the euglena that is able to contract.
Pellicle: membrane that envelops a euglena.
Chloroplast: organelle of the euglena responsible for photosynthesis.
Nucleolus: spherical body that contains the nucleus of a euglena.
Stigma: light-sensitive part of a euglena.
Flagellum: long, mobile filament used by the euglena for locomotion.
Discussion
In our lab we observed different kinds of protists and their unique attributes. We discovered how the euglena move using flagella while the paramecium move using cilia. We also learned that while some protists obtain energy by photosynthesis others use pseudopods to capture and engulf their energy source. We also observed that every protist has similar structures including a nucleus, and cell wall. Our results show that while these organisms show evolution from a common eukaryotic cell, they have all diversified to become unique and varying protists.
Sources
-Reece, Jane, Lisa Urry, Michael Cain, Steven Wasserman, Peter Minorsky, and Robert Jackson.Campbell Biology. Ninth. San Francisco: Pearson, 2011. Print.
-Simmons, . "Protozoa and Protists." "Minute Life" Lab One[Paget] n.d., n. pag. Print.
-Simmons, . "Protozoa and Protists." "Minute Life" Lab One[Paget] n.d., n. pag. Print.