In this article, the author describes a simulation of a coevolutionary "arms race" and introduce a way of teaching it that lets students use the theory of natural selection to explain the outcomes of the simulation. The simulation uses the numerical cards from an UNO[R] playing card deck to represent the speeds of individuals in populations of…

Describes an automatic pipette washer that is functional, inexpensive, and easy to construct from locally available parts. (KHR)

Describes the construction and use of an inexpensive colorimeter that reliably estimates the phosphorus concentrations in water. Presents a two-step modification to an existing photometer. (SAH)

Presents a student laboratory investigation that tests hypotheses about the uptake of phosphate ions by carrots and yeast. (ASK)

Describes the construction and use of an inexpensive, portable photometer designed specifically for estimating population sizes in yeast cultures. Suggests activities for use with the photometer. (WRM)

Describes the construction of an inexpensive light sensor that can be used to measure irradiance in aquatic habitats. Includes a list of tools and materials, details of construction, and usage of the light sensor. (DDR)

Describes two simple laboratory exercises that allow students to test hypotheses concerning the requirement of cell energy for osmosis. The first exercise involves osmotically-caused changes in the length of potato tubers and requires detailed quantitative observations. The second exercise involves osmotically-caused changes in turgor of Elodea…

Described is the construction and use of an osmometer that is low in cost, easy to make, and durable. Materials needed and procedures are outlined. Diagrams show an assembled instrument and individual parts. (RT)

Presented are the results of a survey of biology teachers. Results are compared to surveys of Ohio and Kentucky. Suggestions to improve the coverage of evolution are included. A copy of the survey questionnaire is appended. (CW)

Describes an apparatus that facilitates the quantitative study of fermentation in yeast by allowing simultaneous measurements of fermentation rates in several treatments and a control. Explains a laboratory procedure in which the apparatus is used. Several suggestions for further investigations are included. (Author/RT)

Uses diagrams to aid in describing a simple, rapid technique for staining the nuclei of pollen grains that have been germinated in vitro. (ZWH)