SCIENTIFIC INVESTIGATION IN BIOLOGY

Collection of Specimen

We have defined biology as the study of living things. For effective study, a biologist may have to collect some living things or some parts of living things for observation and analysis. The living things or parts of living things that are used for biological study are called specimens. Biological studies always take place in laboratories. A laboratory is a building or a room that is designed and equipped for scientific studies. Collections of living things especially animals may not be very easy. Some of the animals are not easy to catch while some are quite dangerous. Knowledge on proper specimen collection and handling of is very important. We will discuss some of the apparatus used in specimen collection.

1. Apparatus for Specimen Collection and Preservation

                    Apparatus/Material                                                       Use

              Pooter/Aspirator                        Sucking small insects safely

            Pitfall trap                      Trapping crawling insects or animals

            Soapy water                      Used in traps for drowning insects

          Forceps                   Picking small specimens without damage

Sweep net / Aerial net                           Catching flying insects

           Light trap               Attracting and trapping nocturnal insects

             Tullgren funnel       Extracting small animals from soil/litter

          Envelopes                                     Holding butterflies or moths

Labels & Permanent Ink                        Marking collected specimens

           Hand lens                                         Magnifying small features

             Tracing paper                       Drawing and recording features

Gloves and Digger                                  Safe and effective soil specimen collection

Apparatus/Material        Use

              Knife or Secateurs                          Cutting plant parts

            Collecting bags                                 Transporting specimens

1. Sweep net

This is used for catching flying insects.

• Fish net

This is used for trapping small fish and other small water

• Pooter

This is used for sucking small animals from rock surfaces or barks of trees.

Bait trap

This is used for attracting and trapping small animals including rats.

• Pit fall trap

This is used for catching crawling animals.

• Pair of forceps

This is an apparatus used for picking up small crawling animals e.g. stinging insects.

• Specimen bottles

These are bottles used for keeping collected specimen. They are of different sizes depending on the size of the specimen being studied.

• Magnifying lens

This is used to enlarge small objects. A hand lens is a common magnifying lens used in the laboratory. The magnifying power of the hand lenses is always indicated on the lens e.g. X10, X5, X8. The magnifying power of a lens shows how many times the image will be enlarged compared to the object.

How to use a magnifying lens

-To use a magnifying lens, place the object to be enlarged on the bench. Hold the magnifying lens on one

hand and while closing one eye, move the lens towards the object until the image comes into clear focus.

-If a magnifying lens is used to make a drawing of a specimen, the magnification of the drawing will have no

relation with the size of the drawing.

The magnification of the drawing can be calculated using the formula shown below.

Drawing magnification= length of drawing/length of actual object

The multiplication sign must come before the magnification value e.g. X10, X5, X15 etc.

Precautions During Collection and Observation of Specimen

While collecting specimen for observation, a biologist should play close attention to the following:

 Collect only the number of specimen you need; do not collect more than you need.

 Do not harm the specimen during the capture/collection exercise.

 Do not destroy the natural habitat of the specimens.

 Handle dangerous/injurious specimens with care. Such injurious specimens can be stinging plants or insects.

Forceps and hand gloves should be used in such cases.

Techniques in Collection, Processing, and Preservation

1. Plant Specimens
   1. Collection: Use secateurs/knife to cut leaves, flowers, or small branches.
   1. Processing: Press using blotting paper and weight.
   1. Preservation: Dry, mount on paper, and label (common name, scientific name, locality).
   1. Storage: Keep in dry, insect-free environments.
2. Animal Specimens
   1. Collection: Use pooters, nets, pitfall traps depending on size/type.
   1. Processing:
      1. Sort by type.
      1. Mount on soft boards (for insects).
   1. Preservation:

o Use ethanol or formalin (wet preservation). o Label properly (name, date, locality).

Project-Based Learning (PBL) – Specimen Collection Project Requirements:

• Plan the project (set objectives, timeline, and resources).
  • Budget (include transport, containers, materials).
  • Collect both plant and animal specimens.
  • Record and document each step (photos, labels, notes).  Reflect and present to class or school science fair.

Grade 10 Complete Notes CBC Senior School