Synopsis

This exercise is designed to introduce the science major to the production and use of simple graphs in biology. The students are first introduced to the general principles to be followed in producing a graph. Then scatter graphs, best fit lines, line graphs and column graphs are presented. The concepts of dependent and independent variables, slope, extrapolation and distribution frequency are introduced. Next, the students are given data to graph for themselves. The exercise also includes questions that require basic interpretation of the graphed data.

Technical guide

1. Hazards: none known

2. Computer requirements: At Southwestern College we use Macintosh™ 6100 or 6200 level computers. These seem to work well as long as they have at least 16mb of RAM. Check the memory and speed requirements for the graphics software package you intend to use.

List of Supplies (for a class of 24, working in pairs)

This exercise is designed to introduce the science major to graphing. Techniques utilized include use of computers with graphical analysis software. It assumes that the students have been introduced to the use of computers with graphical analysis software in earlier lab exercises. The Cricketgraph™ graphing software package includes a tutorial. We recommend that the students familiarize themselves with Cricketgraph™ by using the tutorial before attempting this exercise. The use of the tutorial can easily be combined with another short lab exercise (e.g. we introduce the use of the computer and word processing on the same day). Then in a separate lab period, this graphing exercise is assigned along with another short exercise (e.g. we also introduce the use of the micropipetor on that day). Then during the week, we allow the students open computer time to work on the exercise. 

Use of this lab exercise with out the computers and graphics software is quite possible.

At Southwestern, we introduce word processing and graphics software as early in the biology major’s sequence as is reasonably possible. From that point onward we also have the students creat all of their assignments using these software packages. We also try to have the students use the same graphing and word processing software in the other courses that the Biology Major will be likely to take. Certainly it is our intention that the students become proficient with these software packages by the time they transfer to the 4 year institution. We chose Cricketgraph™ and Microsoft Word™ because our primary transfer institution (San Diego State University) uses these software packages.

Tips to make the exercise run more smoothly

1. Make sure that your computers are running the software without any problems the day before the lab period.

2. Check to make sure that all of the computers are able to print. 

Answers to questions

1. Answers to assignment 1 questions

a) Plant 1: 2 week slope = 1.8 cm/ day. Day 8 to day 12 slope = 1.6 cm/ day.


b) Plant 2: 2 week slope = 1.8 cm/ day. Day 8 to day 12 slope = 0.5 cm/ day. 

a) Yes, because it clearly demonstrates distribution frequency. 

b) No, column graphs do not show averages. 

a) 2 week slope = 0.2 cm/ day. Day 5 to day 9 slope = 0.3 cm/ day.
Day 9 to day 14 slope = 0.7 cm/ day

This lab exercise was developed in part with the support of National Science Foundation (Division of Undergraduate Education) grant # DUE 9552290

and California Community College Chancellor’s Office (Curriculum and Instructional Resources Division, Special Projects) grant # FII 95-621-001.