Explain specimen preservation methods and identify a herbarium.

5. During class activity, Mwalimu listed the following as methods of specimen preservation: Wet preservation, dry preservation, embedding and freezing.

a) Why is it necessary to preserve collected specimens?
To allow for long-term study and reference, facilitate identification, and serve as educational material.

b) Briefly explain the following methods of specimen preservation:

i) Wet preservation
Specimens are immersed in a liquid preservative (e.g., formalin or alcohol) to prevent decomposition and maintain their original shape and structure.

ii) Dry preservation
Specimens are dehydrated to remove moisture, which inhibits microbial growth and decay, often involving air-drying or desiccation.

iii) Freezing
Specimens are stored at very low temperatures to halt biological processes and prevent decomposition, preserving cellular structures.

c) How are insect specimens dry preserved?
Insect specimens are typically killed, pinned, and then air-dried in a controlled environment to remove moisture, often in an insect box with a desiccant.

6. Grade 10 learners of Maseno school went to a museum to study preserved collection of medicinal plants.

a) What is the name given to a collection of preserved dry plant specimens?
Herbarium

b) List any three details that should be indicated on the label of each preserved dry plant specimen before storage.

• Scientific name (genus and species)
• Date of collection
• Location of collection (habitat, geographical coordinates)
• Collector's name
• Any unique features or observations

c) Name any two apparatus that can be used to collect plant specimens for preservation purposes.

• Secateurs/Pruning shears
• Trowel/Spade
• Plant press (for flattening and drying)