Mystery graph: Japanese knotweed (Fallopia japonica)
Author
Sarah Morrisseau
Gulf of Maine Research Institute
Vital Signs Program
Question
How do scientists use graphs to understand how species change over time?
Overview
Use this activity to kick off a Vital Signs investigation focused on invasive Japanese knotweed (Fallopia japonica). Use your graphing skills to figure out and explain what happened during a 3-week study of Japanese knotweed growth. Japanese knotweed’s early, aggressive spring growth helps it out-compete native species for sunlight, space, and nutrients.
Science & Technology Standards (MLR)
A3 Constancy and Change Students describe how patterns of change vary in physical, biological, and technological systems.
B1 Skills and Traits of Scientific Inquiry Students plan, conduct, analyze data from and communicate results of investigations.
B1d. Use mathematics to gather, organize, and present data and structure convincing explanations.
B1e.Use logic, critical reasoning and evidence to develop descriptions, explanations, predictions, and models.
E2 Ecosystems.Students examine how the characteristics of the physical, non-living environment, the types and behaviors of living organisms, and the flow of matter and energy affect organisms and the ecosystem of which they are part.
E2b.Describe ways in which two types of organisms may interact including competition, and predator/prey.
Grade Level
7, 8
Setting
Classroom
Materials
Computer & projector
BBCNews video on the VS blog:
(Direct link:
Time Needed
30-40 minutes
Activity Procedure
NOTE: For best results, play Oh Deer! Invasive Species Style to introduce the concept of change over time, and the skill of visualizing data and telling stories using simple graphs.
- Present to students the following “mystery graph” of real scientific data.
- Challenge students to explain what happened over the 3-week study. Ask them to tell the “graph story,” just like they did during the Oh Deer! Invasive Species Style game. They may find their Oh Deer! graph trends and stories useful as they try to make sense of similar trends in this one.
- Give students enough time to think about, talk through, and maybe even write down what they think is happening over time. The mysterious story ramblings might go something like this:
- This plant started out really short (0!), probably from a seed.
- 21 days later was over 100cm tall
- The growth was faster in the beginning, and then started slowing down around Day 13/14
- Once students have been given a chance to look at and process the trend, give them more information about the graph using a video “hint.” Show the BBC News video: Superweed Japanese knotweed’s astonishing growth.
(Direct link:
- Based on what they saw in the video of Japanese knotweed, have students fill in the “mystery graph” with a title and legend. It should look something like this:
- Have students tell the story (or improve the story they started in step 3) of how this plant has changed over time.Draw on the Oh Deer! experience and the BBC News video.
The graph storymay be written (1) in table form, (2) directly on the graph, or (3) using pictures depending on student choice or preferred learning style (examples are below):
(1)Graph story presented in table form:
Day 1 / No growth…yet! Looks like a very boring, empty plant pot.Day 3-13 / Japanese knotweed plant height is increasing at a steady, fast rate
Day 14-19 / Japanese knotweed height is still increasing, but not as quickly as it was before. The video shows the plant getting wider with more branches instead of getting taller.
Day 20-21 / Boring plant pot, no more! Japanese knotweed plant has grown taller than 1 m in just 3 weeks!
(2)Graph story presented in the form of an annotated graph:
No growth….yet.Japanese knotweed plant height is increasing at a steady, fast rate
(3) Graph story presented using drawings:
DAY 5DAY 21
- Share and compare stories.
- Prepare to go look for Japanese knotweed in your community during your own Vital Signs investigation.