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Lesson 2

Intro to Modeling:

Graphing and Analyzing Phenology Data

NGSS Objectives:

HS-LS2-2. Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems of different scales.

HS-ESS3-1. Construct an explanation based on evidence for how the availability of natural resources, occurrence of natural hazards, and changes in climate have influenced human activity.

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Lesson 1 Review

What happened in 2012 to Michigan cherries?

What did we discover through our data sets?

Bloom Date
Average March Temperature

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2012

Review: What story do these graphs tell?

Avg. March Temp. over Time

Bloom Date over Time

Review:

Ask students, “So what do these two graphs tell us? Are there any years that stand out? (What about 2012?)

Can you draw any conclusions from this graph?

Would these graphs support our hypothesis that warmer temperatures lead to earlier bloom dates? Why or why not?

Students could note things like: the graphs are almost inverses of one another, dots start out closer together and seem to spread out over time on each graph
Students confirm that 2012 was a very warm March and that the bloom also occurred very early that year.
So it does seem like there might be a relationship between average March temperature and bloom date. Looks like perhaps when average March temperatures are warmer, the cherries bloom earlier, and when average March temperatures are cooler, the cherries bloom later.

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What do you think phenology means?

Did you know we have been studying phenology?

Introduce/define concept of phenology: “The timing of when the cherry trees blossom and all of these other events you described are examples of “phenology. What do you think phenology means?” (Help students come to understanding/definition, writing the definition up on the board as needed.)

Literal meaning: “The science of appearance.”
Roots: Pheno: “to show or appear” and Logos: “to study”
Definition: Phenology refers to recurring plant and animal life cycle stages. It is also the study of these recurring plant and animal life cycle stages, especially their timing and relationships with weather and climate. (Cite: National Phenology Network)
Definition of “Phenophase”: An observable stage or phase in the annual life cycle of a plant or animal. (The actual stage, “flower bloom” for example, is called a “phenophase.”)

Image: National Phenology Network: http://images.slideplayer.com/26/8525066/slides/slide_4.jpg

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Let’s learn more about phenology!

Video: Phenology and Nature’s Shifting Rhythms

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How can we use �phenology to help cherry farmers?

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Homework Review:

How else could we graph the data to better see the relationship between Avg. March Temperature and Bloom Date?
How could this help cherry farmers?

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Create a graph to predict Bloom Date based on Avg. March temp:

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What would be the:

Independent & dependent variables?
X and Y axes?
Units?
Title of the graph?

Think-Pair-Share:

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Bloom Date of Tart Cherries in Michigan

as a function of Avg. March Temperature

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Bloom Date of Tart Cherries in Michigan �as a function of March Temperature

What can you add to the graph to better predict Bloom Date based on Average March temp.?

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Estimate the “line of best fit”

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Bloom Date of Tart Cherries in Michigan �as a function of March Temperature

We determined we should add the line of best fit. How do we find that? (Get student ideas)

Have students estimate the line of best fit on their graphs on Lesson 2 Worksheet using a straight edge, like a ruler or the edge of a book. Share/compare their line of best fit with their groups and with the with other students around the class. Students could also use rulers or string to show others their estimates on the projected image.

The line you added to your graphs is called a line-of-best-fit, or a trend line. A line-of-best-fit is a linear average of all data points. This means the line is as close as possible to all data points. The line-of-best-fit can be used to identify any patterns in your data because it summarizes the relationship between the independent and dependent variable.

NEXT slide: Show students the slide showing line of best fit

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Blooming Date of Tart Cherries in Michigan as a function of March Temperature

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What does this tell us about the relationship between variables?

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Why might we want the equation for this line?
What would the equation look like?

Blooming Date of Tart Cherries in Michigan �as a function of March Temperature

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Blooming Date of Tart Cherries in Michigan as a function of March Temperature

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What does the equation mean?

y = -1.3(x)+173.22

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y = mx + b

What is x?

Blooming Date of Tart Cherries in Michigan as a function of March Temperature

y = -1.3(x)+173.22

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y = mx + b

What is y?

Blooming Date of Tart Cherries in Michigan as a function of March Temperature

y = -1.3(x)+173.22

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y = mx + b

What is m?

Blooming Date of Tart Cherries in Michigan as a function of March Temperature

y = -1.3(x)+173.22

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y = mx + b

What is b?

Blooming Date of Tart Cherries in Michigan as a function of March Temperature

y = -1.3(x)+173.22

June 21!

b = the Y value

When X = 0

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What does the

equation enable us to do?:

y = -1.3(x)+173.22

tells us

Bloom Date = -1.3(Temp.) + 173.22

Use the rest of class time to predict Bloom Date based on Avg. March Temperature!

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Blooming Date of Tart Cherries in Michigan as a function of March Temperature

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Can you use the line of best fit to predict the bloom date if Avg. March temp. is: 25 degrees? 30? 45?