Study of Plant and Animal Specimens: Museum Practical

A museum specimen is a real plant or animal that has been preserved so students can study it long after it was collected. Plants are usually dried and pressed onto sheets called herbarium sheets, while small animals are kept in glass jars filled with a preservative liquid such as formalin. In this practical you observe these preserved specimens, read their labels and draw labelled diagrams of what you see.

This practical matters because textbooks can only show pictures, but a museum jar lets you see the actual body plan of an earthworm, a frog or a fish. Learning to read labels, identify external features and record adaptations trains you to think like a taxonomist, the scientist who classifies living things.

Key Concepts

• Specimen: an individual plant or animal preserved for scientific study.
• Herbarium sheet: a dried, pressed plant mounted on thick paper with a label giving its scientific name, family, collection date, place and collector.
• Formalin: a preservative liquid (about 10 percent aqueous solution of formaldehyde) used to keep animal specimens from decaying in museum jars.
• Label: a slip inside or on the jar recording the scientific name, common name, habitat and date of collection. Always read it before observing.
• Adaptation: a body feature that helps the organism survive in its habitat, such as the streamlined body of a fish or the clitellum of an earthworm.
• Taxonomic characters: the observable features (segmentation, appendages, fins, scales) used to identify and classify a specimen.

How It Works

1. Pick up a museum jar carefully and first read the label without shaking the specimen.
2. Observe the specimen from outside the glass: overall shape, size, colour and symmetry.
3. Note the major body regions and special structures — for example segments and setae in an earthworm, fins and scales in a fish, or moist skin and limbs in a frog.
4. For a plant herbarium sheet, study the root, stem, leaf arrangement, flowers or fruits, and note any adaptations to its habitat.
5. Record your observations in a table and draw a neat labelled diagram in your practical file.

Worked Example

You are given a jar labelled Pheretima posthuma (common earthworm). The specimen measures 150 mm from the first to the last segment, and you carefully count 115 segments along its body. To find the average length of one segment, divide the total length by the number of segments: 150 ÷ 115 ≈ 1.30 mm per segment. This matches the textbook range of about 1 to 1.5 mm per segment for this species, so your identification is consistent. You then note the cylindrical segmented body, the swollen clitellum band near segments 14 to 16, and record that these features suit a burrowing life in moist soil.

Common Misconceptions

• "The animals in the jars are sleeping or alive." They are not alive. They were preserved after death so their bodies could be studied for years.
• "The liquid in the jar is just water." It is a chemical preservative, usually formalin, which is toxic. Never open a jar or touch the liquid.
• "Memorising names is enough." The practical tests your observation skills: examiners ask you to point out features and explain adaptations, not just recite names.

Real-World Applications

• Museums keep reference collections that scientists use to identify new species and track biodiversity.
• Doctors and farmers use preserved specimens to identify parasites, pests and medicinal plants.
• Forensic experts compare specimens to identify plant or animal material found at a scene.

In short, this practical teaches you to observe preserved plants and animals carefully, read their labels, identify key body features and connect those features to the organism's way of life. Draw clean labelled diagrams, and always handle jars gently because the specimens inside are irreplaceable.