Bark Beetle Outbreak
Phenomenon:
Bark beetles are attacking forests across the Western United States and Canada, resulting in the death of many trees.
Student Task:
Construct an argument based on evidence for the cause of the recent bark beetle outbreak.
Model
Use a computer model to investigate the effect of rising temperatures on the number of bark beetle outbreaks over time.
Investigate
Plan and carry out an investigation to determine the effect of temperature on beetle life cycle.
Obtain Information
Obtain information about how a tiny bark beetle can cause the death of a large tree.
Analyze Data
Analyze data to identify changes in the forest ecosystem that could be associated with the recent bark beetle outbreaks.
Explanation:
Bark beetle outbreaks are increasing in number and intensity largely due to a rise in global temperature. Warmer temperatures affect the timing of bark beetle growth and development and increase the number of beetles that survive the winter.
NGSS Standard:
MS-LS2-4. Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations.
[Clarification Statement: Emphasis is on recognizing patterns in data and making warranted inferences about changes in populations, and on evaluating empirical evidence supporting arguments about changes to ecosystems.]
Utah SEEd Standard:
Standard 6.4.4 Construct an argument supported by evidence that the stability of populations is affected by changes to an ecosystem.
[Emphasize how changes to living and nonliving components in an ecosystem affect populations in that ecosystem.]
Additional Resources:
- Spruce Tree and Beetle Images View Download
- Earth Systems Model Worksheet View Download
- Computer Model Download (updated October 2017)
- To run the computer model, you must first download and install NetLogo 6.0. Go to NetLogo free download page.
- Worksheet for Computer Model View Download
Recommended Teaching Sequence:
Day 1: Make observations of infested trees to predict how bark beetles and trees interact in a forest ecosystem. Read to obtain information about how a tiny bark beetle can cause the death of a large tree.
Day 2: Plan and carry out an investigation to determine the effect of temperature on the beetle life cycle.
Day 3: Develop and use a model to describe how access to resources can limit the growth of bark beetle populations (and the scale of an outbreak).
Day 4: Analyze data to identify changes in the forest ecosystem that could be associated with the recent bark beetle outbreaks.
Day 5: Use a computer model to investigate the effect of rising temperatures on the number and intensity of bark beetle outbreaks over time.
Day 6: Construct an argument supported by evidence for the cause of the recent bark beetle outbreak.
Formative Assessment:
Use what students have written in their science notebooks as a formative assessment, including the observations they recorded and their written explanation for the phenomenon. Do students understand that small changes in the physical or biological components of an ecosystem can affect populations?
Lesson Contributors:
April Mitchell, Science Coach, Salt Lake City School District
Dr. Lin Xiang, Assistant Professor of Science Education, University of Kentucky