Investigating the Ecology of Goldenrod Galls through Biological Sampling
Initial Publication Date: July 23, 2008
Summary
In this biology field lab exercise, students conduct a stationary population study of goldenrod galls. They examine a host of factors including goldenrod plant density, goldenrod gall density, gall height, gall mass, larval exit hole direction, and larval exit hole angle. Students construct data tables, graph the data, and form conclusions based on their data.
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Learning Goals
1. Describe the life cycle of the goldenrod gall fly.
2. Collect and analyze data.
3. Carry out stationary biological sampling.
2. Collect and analyze data.
3. Carry out stationary biological sampling.
Context for Use
Educational level: grade 11-12
Class size: 25
Institutional type: high school
Type of activity: field exercise
Time required: two 60 minute class periods
Skills or concepts required: fundamentals of ecology
Equipment: tape measure, 4 plot stakes, flagging, 12 flags, calculator, meter stick, mobile balance, compass, protractor
Class size: 25
Institutional type: high school
Type of activity: field exercise
Time required: two 60 minute class periods
Skills or concepts required: fundamentals of ecology
Equipment: tape measure, 4 plot stakes, flagging, 12 flags, calculator, meter stick, mobile balance, compass, protractor
Description and Teaching Materials
A. Background knowledge
1. Read "The Curious World of Galls" from the November/December 2000 DNR Conservation Volunteer.
2. Create a flow chart outlining the life cycle of the
goldenrod gall fly.
B. Construct a stationary plot in the field
1. Lay out a 3 square meter plot.
2. Mark the corners of the plot with corner stakes.
3. Divide the plot into 9 equal subplots.
4. Mark the corners of the subplots with flags.
5. Use flagging to outline the subplots.
C. Determine population density in the stationary plot
1. Count and record the number of goldenrod plants in each subplot.
2. Determine the average number of goldenrod plants per subplot.
3. Count and record the number of goldenrod ball galls in each subplot.
4. Determine the average number of galls per subplot.
D. Examine four different factors in the subplots
1. Randomly choose a subplot: face away from the stationary plot and toss a stick over your shoulder into the stationary plot.
2. Determine the height of each gall in the subplot and record the data.
3. Determine the mass of each gall in the subplot and record the data.
4. For those galls exhibiting a larval exit hole, determine the exit direction and record the data.
5. For those galls exhibiting a larval exit hole, determine the exit angle and record the data.
6. Gather data on height, mass, direction, and angle for two additional random subplots.
E. Graph gall height versus mass
F. Conclusions
1. What does the gall density data suggest?
2. What does the graph of height versus mass tell you?
3. Do you see any trends in gall direction and angle?
4. What questions have arisen in your analysis?
1. Read "The Curious World of Galls" from the November/December 2000 DNR Conservation Volunteer.
2. Create a flow chart outlining the life cycle of the
goldenrod gall fly.
B. Construct a stationary plot in the field
1. Lay out a 3 square meter plot.
2. Mark the corners of the plot with corner stakes.
3. Divide the plot into 9 equal subplots.
4. Mark the corners of the subplots with flags.
5. Use flagging to outline the subplots.
C. Determine population density in the stationary plot
1. Count and record the number of goldenrod plants in each subplot.
2. Determine the average number of goldenrod plants per subplot.
3. Count and record the number of goldenrod ball galls in each subplot.
4. Determine the average number of galls per subplot.
D. Examine four different factors in the subplots
1. Randomly choose a subplot: face away from the stationary plot and toss a stick over your shoulder into the stationary plot.
2. Determine the height of each gall in the subplot and record the data.
3. Determine the mass of each gall in the subplot and record the data.
4. For those galls exhibiting a larval exit hole, determine the exit direction and record the data.
5. For those galls exhibiting a larval exit hole, determine the exit angle and record the data.
6. Gather data on height, mass, direction, and angle for two additional random subplots.
E. Graph gall height versus mass
F. Conclusions
1. What does the gall density data suggest?
2. What does the graph of height versus mass tell you?
3. Do you see any trends in gall direction and angle?
4. What questions have arisen in your analysis?
Teaching Notes and Tips
Students may need help in establishing how to consistently measure gall height, mass, direction, and angle.
Students may need help in establishing which galls to examine: ball galls versus elongated galls versus multiple galls.
Students may need help in establishing which galls to examine: ball galls versus elongated galls versus multiple galls.
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Assessment
Students will be graded on their field work report:
1. Data table summarizing goldenrod plants and galls
2. Calculations of average plants and galls
3. Data table summarizing plant height, mass, direction, and angle
4. Conclusions
1. Data table summarizing goldenrod plants and galls
2. Calculations of average plants and galls
3. Data table summarizing plant height, mass, direction, and angle
4. Conclusions
Standards
Grade level: 9-12
Strand: life science (IV)
Substrand: interdependence of life (C)
Benchmark: matter and energy in an ecosystem (1)
Strand: life science (IV)
Substrand: interdependence of life (C)
Benchmark: matter and energy in an ecosystem (1)