Thin slices of potato can be used to demonstrate the presence of protein, carbohydrates, and nucleic acids at the cellular level. Procedures and materials are provided for these simple tests. Also indicates that the presence of fat can be readily seen by staining avocado with Sudan red or Sudan black. (Author/DH)

Background information on the biology of aphids is supplied. Using this information in a wide variety of investigations, many involving equipment and techniques available in the school laboratory, can be carried out. An appendix lists possible projects. (Author)

Describes a field exercise which links ecology and taxonomy in the teaching of the species concept. Two common hedgerow plants (red and white campions) are used as a pair of "species" that are normally distinct. Plants of intermediate character can be encountered, and the status of these plants is investigated. (Author/JN)

Briefly describes some of the more recent developments in the use of human hairs for such instructional purposes as observing barr bodies and chromosomes, and for culturing to produce cells of both epithelial and fibroblastic morphology. Three main hair categories are also described. (JN)

The carabid beetle (Notiophilus) preys readily on an easily-cultured collembolan in simple experimental conditions. Some features of this predator-prey system are outlined to emphasize its use in biology instruction. Experiments with another potential collembolan are described in the context of developing the method for more advanced studies.…

Presented is a cytogenic technique which enables students to produce preparations of dividing cells. Described are materials, methods, typical results, and assessment for this activity. The usefulness for a wide range of ages and abilities is stressed. (CW)