##
* *Reflection: Vertical Alignment
Using Protists as a Model of Succession (Part 3/3) - Section 3: Looking at Student Logs

Students excel at the compartmentalization of knowledge. They have a difficult time transferring what they learn in math class to science class. This is not a good thing. The math teacher at my high school and I noticed that our students had this problem so we vertically aligned my biology curriculum with the math standards that deal with statistics. Throughout the year, students conduct several short term studies in which they collect enough data to perform a statistical analysis. Therefore, they could see how theoretical mathematics is applied to better understand natural phenomena. This is the second study in which we apply statistics and statistical methods. (*Note: The first lesson is in the virus unit in which we sort large amounts of data and look for patterns. If you would like to view this lesson, it is Understanding Genetic Drift.)*

In today's lesson, I demonstrate to my students the process that scientists use to organize and make sense of their data. By first having them look at their student logs, they are able to notice any changes that are seen in their hay infusions. Further probing questions allow my students to realize that they cannot possibly determine what is happening in their hay infusions using only qualitative observational data. Through the discussion, they realize that they need to sort their data and use some mathematical tools to determine patterns. I ask them if they have any tools in their math "toolbox" that might help them. Invariably, some students suggest we calculate the mean. I encourage them to take their analysis a step further by using additional descriptive statistic algorithms (i.e. standard deviation, range, etc).

Throughout this lesson, students use computerized mathematical tools (i.e. spreadsheets and LoggerPro) in the sorting and organization of their data. I do this for two reasons. We have a limited amount of time to complete this exercise before we must move to the next task which is analyzing and explaining the patterns seen in the data. It is more important that students interpret their data in light of what they know about succession. I would rather have students understand what changes have occurred to the protist populations over time and due to the different treatment. They are learning to correctly compute these statistical algorithms in their math class. Too many times students get bogged down in getting the right answers because of incorrect computation and they never get to analyze and explain their data. Therefore, in this lesson, I just ensure that the data is being inputed properly and then we can evaluate if the numbers make sense in light of our qualitative observational data.

Once students have determine the descriptive statistics for the animal-like, plant-like, and fungus-like protists in their treatments, then I have them determine the line of best fit. Again, we use a computer program to help them. Students have many choices from which to select. I encourage them to select the simplest function that best shows the patterns in the data. In this study, that is typically not a line. Students are surprised by this. This is because they incorrectly assume that a line of best fit is always a linear function. However, when we explain what the graph means in light of their observational data, they come to realize that the function cannot possibly be a linear function. Finally, students explain what has occurred in light of the descriptive statistics and the graph they generated.

By observing this process, students gain a richer understanding of the importance of statistical methods. Later in the year, we add another computational tool, the student t-test. This chunking is very important because it keeps students that struggle with math from being overwhelmed.

*Using Statistics in the Science Classroom*

*Vertical Alignment: Using Statistics in the Science Classroom*

# Using Protists as a Model of Succession (Part 3/3)

Lesson 10 of 11

## Objective: Students will explain how succession occurs in an ecosystem by noting the changes in a hay infusion over a period of time.

## Big Idea: By using protists as model organisms, we can shorten period of time succession occurs so we can observe changes in an ecosystem.

*69 minutes*

This is the end of a two week observational study which started at the beginning of the unit. Students will make one final observation and cell count of their hay infusions. They will discuss their findings and write a formal report. Here is an overview of what students will learn today.

#### Resources

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#### Hook

*13 min*

Students should make wet mount slides of their hay infusions (*as described here*). They should make sketches of what they see at 6 different places on the slide. After ten minutes, have the students clean up their lab areas and return to their desks. Microscope slides should be disposed in the glassware bucket. Since this is the final day of the experiment, students should place the cultures in the autoclave for sterilization.

(*Note: Hay infusion culture should be sterilized at 15 lbs pressure for 15 minutes. After the cultures cool, the liquid contents should be poured down the sink with copious amounts of water. The solid contents should be disposed in the chemical disposal bucket.*)

*expand content*

#### Looking at Student Logs

*30 min*

Have the students discuss their student logs that they have kept over the past two weeks. Ask them the following questions to keep the discussion moving:

- When looking at your data, are there any patterns that you see at first glance?

- What types of changes did you see in your hay infusion over the two week period?

- Is there a way that you could quantify your observations so that you could better see if any patterns emerged?

Guide them in determining a way that they could present their findings in quantitatively. (*Note: Most student groups in decide to compare the change in number of types of protists over time to the different treatment.*)

Student groups will combine all of their group data on a class spreadsheet. (*Note: we use Google docs for this step.*) Data is disaggregated by treatment (*control, salt, and fertilizer*) and type of protist group (*animal-like, plant-like, or fungus-like*). All students should place their data in the same spreadsheet for analysis. Once all the students have completed the input of their data, then ask students how they could compare the distribution of data to get a clearer picture of what occurred to the amounts of different protists in each treatment over a two week time period. To help in this comparison, ask students to calculate the daily average (mean), standard deviation, and range (maximum and minimum) of the class data. (*Note: If your students already have some experience using statistics, then they can also determine the median and variance.*)

Next, students can download the Google doc as a .csv file and import it into LoggerPro to determine the line of best fit. To determine the line of best fit, students should select **Analyze**, then **Curve Fit**. Next, they should select which data set (*animal-like, plant-like,or fungi-like*). Then, they should select the general equation and **Try Fit**. Once they have determined the function that best matches the distribution of their data, they should select **Ok**. Students should repeat this procedure for all data sets (*animal-like, plant-like, or fungi-like*) in each treatment (*control, salt, or fertilizer*).

Move about the room consulting with individual students and answering questions that may arise.

*(Note: Here are some of the student graphs from my class' two work study: Salt treatment (Group 1), Salt treatment (Group 2), Fertilizer treatment, and Control*).

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#### Reporting Student Findings

*10 min*

Using the results of their descriptive statistical analysis and their graph with line of best fit, students will describe what occurred in their hay infusions over the two week period. When writing their descriptions, students should consider the following questions:

- When you first started your hay infusions (day one), how many protists were in the hay infusions?
- What was the first type of protists that occurred in the hay infusion?
- What protist showed up in the hay infusion next?
- What was the final protist group to arrive?
- Explain these observations in light of what you know about protist life cycles.
- What occurred to the hay infusions when salt or fertilizer were added to them?

Students should type their description and include their graphs that were generated in the previous student activity.

*expand content*

Explain the difference between primary and secondary succession. Then ask students to think of ways that their hay infusion might show evidence of succession in an ecosystem.

- Where would one see an ecosystem like the one in the hay succession?
- Where was succession first studied?
- What did scientists discover when studying those ecosystems?
- What is the pioneer plant and animal species?
- Like what does the climax community look?
- Why study a community of protists instead of a mountainside or forest?

Guide students through writing a brief introduction of their paper by projecting a word document and asking for student input. Modeling writing the introduction as the student answer the questions listed above.

Allow the students class time to begin writing the procedure of the experiment. At the end of the writing period, bring students back together as a class. Have several volunteers individually read their procedures. Have students critique the procedure and offer suggestions where these procedures should be more detailed.

Then have students insert the description they wrote in the previous section. Inform students that they have essentially written their formal lab report. They will need to edit it for spelling and convention errors. Their final draft is due in two days.

*expand content*

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- UNIT 1: Phylogeny and Taxonomy
- UNIT 2: Viruses
- UNIT 3: Bacteria
- UNIT 4: Protists
- UNIT 5: Fungi
- UNIT 6: Plants
- UNIT 7: Photosynthesis
- UNIT 8: Cellular Respiration
- UNIT 9: The Cell Cycle
- UNIT 10: The Eukaryotic Cell
- UNIT 11: Invertebrates
- UNIT 12: Molecular Genetics
- UNIT 13: Mendellian Genetics
- UNIT 14: Ecology

- LESSON 1: Using Protists as a Model of Succession (Part 1/3)
- LESSON 2: Using Protists as a Model of Succession (Part 2/3)
- LESSON 3: Monsters Inside Me: Parasitic Protists (Part 1/2)
- LESSON 4: Monsters Inside Me: Parasitic Protists (Part 2/2)
- LESSON 5: Using Algae for Phytoremediation (Part 1/3)
- LESSON 6: Using Algae for Phytoremediation (Part 2/3)
- LESSON 7: Using Algae for Phytoremediation (Part 3/3)
- LESSON 8: Using Protists to Understand Evolution (Part 1/2)
- LESSON 9: Using Protists to Understand Evolution (Part 2/2)
- LESSON 10: Using Protists as a Model of Succession (Part 3/3)
- LESSON 11: How Big Can An Amoeba Get?