Introduction to Microscopy Make a labeled sketch and describe the results obtained: Pond water: Examination of living microorganisms {Insert image here} Viewed at 10X, and 40X Observation {Start typing here} Viewed at 10X, and 40X Observation [5 \times 4 = 20]
The Correct Answer and Explanation is:
Here is a sample correct answer for the worksheet, followed by a detailed explanation.
Correct Answer for the Worksheet
Pond water: Examination of living microorganisms
{Insert image here}
(A labeled sketch of a Paramecium would be inserted here. The sketch should be an elongated oval or slipper shape. Labels should point to the following structures: Cilia (tiny hairs covering the outside), Oral Groove (an indentation on one side), Contractile Vacuole (a star shaped organelle), and Nucleus (a large central organelle).)
Viewed at 10X, and 40X
Observation
{Start typing here}
At 100X total magnification, numerous fast moving, oval shaped organisms were visible. They moved in a spiraling motion across the field of view. At 400X total magnification, the organism was identified as a Paramecium. Its body is covered in tiny, hair like structures called cilia, which beat in coordination to propel it through the water. A distinct indentation, the oral groove, was also visible. Inside the cell, a star shaped contractile vacuole was observed slowly filling and then quickly contracting to expel water.
{Insert image here}
(A labeled sketch of Spirogyra would be inserted here. The sketch should show a long filament made of rectangular cells. Labels should point to the following structures: Cell Wall (the outer boundary of each cell), Cytoplasm (the internal substance of the cell), and a prominent, spiraling green ribbon identified as the Chloroplast.)
Viewed at 10X, and 40X
Observation
At 100X total magnification, several long, unbranched green filaments were observed. These structures were non motile. At 400X total magnification, the filaments were clearly seen to be composed of individual rectangular cells joined end to end. The most prominent feature within each cell was a beautiful, bright green chloroplast arranged in a distinct helix or spiral shape. This identified the organism as Spirogyra, a type of filamentous alga. No locomotion was observed.
Explanation
This “Introduction to Microscopy” lab is a fundamental exercise in biology designed to develop skills in using a light microscope and to reveal the incredible diversity of microscopic life in a common environment like pond water. Pond water is an ideal subject because it is a rich, self contained ecosystem teeming with a wide variety of microorganisms, including protozoa, algae, bacteria, and small invertebrates.
The exercise requires observing samples at different magnifications. Starting at low power (10X objective, for 100X total magnification) allows the student to scan the slide and locate organisms. Once an interesting specimen is found and centered, switching to high power (40X objective, for 400X total magnification) provides a much more detailed view of its structure and behavior.
The first observation describes a Paramecium, a classic example of a protozoan. It is a single celled heterotroph, meaning it consumes other organisms for energy. Its movement, powered by thousands of beating cilia, is a key characteristic. Observing its internal structures, like the contractile vacuole which regulates water balance, provides insight into the complex functions occurring within a single cell.
The second observation focuses on Spirogyra, a representative green alga. Unlike the motile Paramecium, Spirogyra is a non motile, filamentous autotroph. It performs photosynthesis to create its own food, a process carried out in its unique spiral chloroplasts. Comparing these two different organisms, one animal like and one plant like, highlights the vast range of survival strategies that have evolved in the microbial world. Making labeled sketches is a critical scientific practice that forces close observation and creates a permanent record of the findings.
