AP Biology - Graphing Assignment

You will need to know how to read and complete graphs to complete AP biology. Graphs will be included in each lab and will likely be included in the final AP test.

I. Basic Graph Rules

When using graphs, keep the following information in mind:

Always include a short title with a short description of what is illustrated by the graph.

The dependent variable goes on the y-axis (vertical) and the independent goes on the x-axis (horizontal). To figure out dependent/independent, put the two variables in a sentence and see which causes a change in the other. For example, if you are graphing the number of mosquitoes observed per month, does it make sense to say the month changed because the calendar is dependent upon mosquito populations, or the mosquito populations changed because of they are dependent on the conditions in a given month? Obviously, mosquitoes are dependent upon given weather conditions, so the month is the independent variable while mosquito numbers are the dependent variable.

Always label the category and units for each axis.

Use the full graph. A graph is used to visually illustrate a conclusion, so it makes no sense to leave 50% of the available space blank. How do you make sure the graph takes up the whole space? Count the number of units used in your data set and divide by the number of spaces available on your graph. For example, if you are measuring 100 degrees and there are 20 boxes available on your graph, you get 5 degrees/1 box.

We will use three types of graphs in this class. Bar graphs are useful for comparing different experimental treatments. Line graphs are useful for showing changes over time. Pie charts are useful in illustrating how a resource is divided up.

II. Specific Information on Linear Graphs

When doing a linear graph, we will use Excel to calculate a best-fit line.\

Instructions for best-fit line graph using Excel:

Type data for independent variable in first column (ignore headings) and data for dependent variable in second column (ignore headings).

Highlight all cells w data and select INSERT (top option bar), select Chart (from dropdown menu).

If you are doing a line graph:

When chart options appear, select SCATTER (from options under Chart Type) and SCATTER (from Chart Sub-type option on right side of screen).

Hit ‘Next’ and graph will appear. Place cursor on a data point and right click. Select option ‘Add Trendline’ and an option box with two tabs will appear. For tab labeled ‘Type,’ selection LINEAR; for tab labeled ‘Options,’ check boxes for DISPLAY EQUATION and DISPLAY R SQUARED.

Drag equations off chart, place just under the legend.

Check that you have added a title, labeled both y and x- axis, and included proper units.

Print or email graph to Mr. Lovrien

Data Sets to Complete (not all will be linear graphs!):

AP Courses

# of AP Courses Completed % of Students finishing College in 4 Years

29

45

61

II. AP Tests at Brandon Valley High School.

Graph Percentage of Students Taking an AP Exam (2002 – 2009)

School Year Students at BVHS Students taking AP Test

2002 794 55

2003 807 39

2004 831 48

2005 800 46

2006 872 41

2007 875 59

2008 895 46

2009 969 49

2010 981 63

III.

Temperatures were obtained in November in a fairly arid area of Nevada. At two different sites, temperature readings were taken at a number of heights above and below the soil surface. One site was shaded by a juniper (a plant) whereas the other was not.

Table 1

Condition	Height in cm from soil surface	Temp. in Co - Beneath Forest Cover	Temp in Co – Unshaded Field
Air	150	18	20
Air	90	18	21
Air	60	18	20
Air	30	18	21
Soil surface	0	16	33
Humus	-6	12	19
Mineral	-15	9	15
Mineral	-30	7	12

Graph the temperature of the air at the various temperatures recorded in the data table. Include results for shaded and unshaded areas.

IV.

A researcher interested in the disappearance of fallen leaves in a deciduous forest carried out a field experiment that lasted nearly a year. She collected all the leaves from 100 plots scattered throughout the forest. She measured the amount of leaves present in November, May and August. The percentages reflect the number of leaves found, using the November values as 100 percent.

Collection Date	Ash	Beech	Elm	Hazel	Oak	Willow
November	4271g 100%	3220g 100%	3481g 100%	1723g 100%	5317g 100%	3430g 100%
May	2431g 57%	3190g 91%	1739g %	501g %	4401g 83%	1201g 35%
August	1376g 32%	2285g 71%	35g %	62g %	1759g 33%	4g 0.1%

Complete the table by calculating the missing percentages

Construct a graph for the % of leaves on ground for each species of tree.

V.

A team of scientists wanted to test the effects of temperature on the germination rate of pinto beans. They

placed three sets of 100 pinto bean seeds in temperature controlled chambers: Chamber A was set at 15o

C, chamber B at 20oC, and chamber C at 25oC. Their results are shown in Table 4 below:

Germination Rates of Pinto Beans
Day	% Germination (15o C)	% Germination (20o C)	% Germination (25o C)
0	0	0	0
2	2	10	10
4	10	30	50
6	20	40	80
8	20	60	90
10	35	70	90

Construct a graph from the above data.