Q1.
Did you also observe any of these microorganisms or something different? Record in your notebook and discuss in your class.
Answer
Do the observation first, then record exactly what you saw — shape, whether it moves, whether it is green — and only then try to name it. The two tables in the book (Tables 2.1 and 2.2) are the record made by a group of Grade 8 students; yours should be built the same way.
What the book's record shows:
| Table 2.1: Organisms present in pond water | ||
|---|---|---|
| S.No. | Microorganism observed | Recorded data |
| 1. | Amoeba (Protozoa) | Single cell, moving, irregular shape |
| 2. | Paramecium (Protozoa) | Single cell, moves from one place to another, movement takes place with the help of specialised structures |
| 3. | Algae | Single cell, looks green because of the presence of green pigment, movement takes place with the help of specialised structures |
| Table 2.2: Organisms present in soil suspension | ||
|---|---|---|
| S.No. | Organism | Remarks |
| 1. | Bread mould (Fungi) | Branched filament without chlorophyll having sac-like structure |
| 2. | Mould (Fungi) | Branched filament without chlorophyll having brush-like structure |
| 3. | Algae | Spherical, presence of chlorophyll — a green pigment |
| 4. | Bacteria | Spherical, comma, spiral or rod-shaped, one long hair-like structure and many small hair-like projections around the cell |
Sample answer: “In pond water I saw two kinds of organisms. One was a single cell with no fixed shape that slowly changed its outline as it moved — this matches Amoeba. The other was green and rounded and drifted about — a single-celled alga. In the soil suspension I found short rod-shaped bodies that were not green, and one branched thread with tiny round heads on it, which matches a mould. I did not see Paramecium.”
Tip: use the four columns of the book's tables as your own headings — shape, single cell or many cells, green or not green, moving or still. Those four observations are enough to place almost anything you see into protozoa, algae, fungi or bacteria. And follow the book's instruction in Activity 2.5: do not touch the soil with your bare hands — use a spoon or gloves.
Why the soil is left to settle: when you stir soil in water, the heavy grains sink but the very fine particles stay suspended — this is the soil suspension. A drop taken from the top layer after settling has few heavy grains to block the view, so the tiny organisms in it can actually be seen.