Lesson 4 – Scaling up: Linking cells in a drop of seawater to global patterns

Objectives

See the NGSS listed as buttons in the left-hand menu and in the chart below. The buttons on the left are grouped to show the integrated three-dimensional nature of our lessons and modules. When applicable, if NGSS are addressed outside of bundles, they are listed separately. Connections to 21st Century Learning Skills and other published standards are also included in the chart below. In addition, for this lesson, here is a breakdown of:

What Students Learn

• Different types of phytoplankton have different patterns of distribution across the globe, due to abiotic and biotic differences
• There are multiple ways to collect data on phytoplankton distributions and diversity on global scales, which may lead to different “answers” on the details of their distributions.
• How to collect data from different types of figures and present the data in a new way
• How to combine two important tools – DNA analysis and flow cytometry to determine how many of which phytoplankton groups are present
• How to interpret chlorophyll data gathered from a satellite and identify its advantages and disadvantages
• Ecosystem models can be used to test what we know about a system
• Ecosystem models help scientists expand small-scale observations to study global processes

What Students Do

• Watch a video of a model of phytoplankton distributions across the globe (Darwin Model)
• Answer questions and engage in discussion to capture their initial level of understanding of how phytoplankton distributions and diversity can be determined across the globe
• Use data to ask how phytoplankton populations change across the Atlantic Ocean
• Work in small groups to collect information from three different sets of data and plot the data on a new graph
• As a class, compare graphs and discuss any differences
  Revisit the Darwin Model video and discussion questions to evaluate types of evidence and how they can be used to predict changes in ecosystems over time
• (Problem based learning option) Revise drops of water to include new information from the lesson

Overview

Introduction:

Students learn about ecosystem diversity and distribution of ocean phytoplankton by answering the question, “Who is there?” Student groups will be presented with three different sets of ocean data gathered from the Atlantic Meridional transect (from North to South in the Atlantic Ocean) and will apply what they’ve learned in Lessons 2 and Lesson 3 to interpret the data and answer the question, “Who is there?” Students will explore the different scales used to look at microbial ecosystems globally through different types of data. Students may get different answers to that question depending on which of the three datasets they work with and which tools were used (DNA analysis, flow cytometry and chlorophyll satellite imagery). Through discussion and evaluation of these differences they come away with an understanding of the advantages and disadvantages of different types of microbial and oceanographic measurement techniques and scales. Along the way students will learn that the patterns of relative abundance can change depending on location in the ocean (ecosystem). Ultimately they expand their knowledge of ecosystem dynamics which drive oxygen production in global ocean systems. For more advanced data analysis and skills, using publicly available ocean data continue on to Lesson 5.

Instructions

Part I: Introducing the model and case study (~90 min)

Step 1: Introduce the Darwin Model (using Slide 1-2.) in a basic way by explaining that it is a computer generated model, using ocean current data and 4 different types of phytoplankton living in a dynamic ocean. Each group of phytoplankton is colored red, blue, green, or yellow. (2 min)

Step 2: Hand out Worksheet 1 (Google Doc | Word Doc) to all students. Show Video in (Slide 2) (repeat a few times as needed), while students discuss questions provided in Worksheet 1. Have a “scribe” from each group, record the group’s answers (or record as individuals). Tell students to leave space for new thoughts when these questions are revisited at the end of the lesson. They will have to make educated guesses to many of the questions, pulling on what they’ve learned in previous lessons of this module (10 min). See Worksheet 1 _Teacher key (Google Doc | Word Doc) for additional guidance.

Step 3: Next, use Slide 3 to introduce students to the case study they will work on. The goal of the activity is to answer the question: How does phytoplankton abundance and diversity change from North to South in the Atlantic Ocean? Tell them they will explore three different types of data that could be used to achieve a global understanding of phytoplankton distribution. They will answer the question by graphing phytoplankton distribution and diversity using Datasets 1-3, each collected with a different oceanographic approach. The aims are 1) Test how well the Darwin Model represents phytoplankton diversity in the Atlantic Ocean, 2) Explore how different datasets might address this question, 3) Identify advantages and disadvantages of different types of data for addressing this question All of the data is collected from an area (transect) across the North and South Atlantic studied as part of multidisciplinary research called the Atlantic Meridional Transect (AMT) program (5 min).

Step 4: Next, divide students into 8 groups of 3-4. All groups will receive Dataset 1 (Google Doc | Word Doc), which explores the use of satellite data to assess phytoplankton distributions. Have them complete the questions and graph the data. Circulate among groups answering questions. See Dataset 1_Teacher key (Google Doc | Word Doc) for additional guidance. (10 min)

Step 5: Next, give half of the groups Dataset 2 (Google Doc | Word Doc) that uses flow cytometry and DNA sequencing to study distribution patterns. Give the other half Dataset 3 (Google Doc | Word Doc) that uses laboratory culture studies to estimate phytoplankton distributions.

Step 6: Have students discuss and complete the corresponding graphs and associated questions, including comparison to their graph from Dataset 1. Circulate among groups and see Dataset 2_Teacher key (Google Doc | Word Doc) and Dataset 3_Teacher key (Google Doc | Word Doc) for additional guidance. (20 min.)

Part II – Present, Evaluate and Discuss Datasets (~30-40 min.)

Step 1: Invite a representative from each group to present their graphs from each dataset. This could be done by drawing graphs on the whiteboard, or the teacher could compile all graphs from worksheets and display via powerpoint or overhead projector. (5 min).

Step 2: Discuss as a class (or in small groups) what differences exist between the datasets and the answer that each group came up with. Remind students the focus question is: How does phytoplankton abundance and diversity change from North to South in the Atlantic Ocean? Use the questions associated with each dataset as a guide for the discussion. (10 min.).

Step 3: Revisit the Darwin Model, showing the video as before (Slide 4). Discuss with the students how all the data they have studied may have contributed to such a video-model? What data is represented by the colors? Which types of phytoplankton correspond to which color? Is there abiotic ( nutrient, light or temperature) data? How is the population or distribution (concentration of phytoplankton) data represented? What are the limitations of the approach compared to satellite or ship-based sampling? What are the advantages? What other information could scientists use to make this approach more powerful?*

Step 4: Have students revisit Worksheet 1, recording any changes to their answers. They should capture how their understanding of information on phytoplankton from one sample can be expanded to understand global patterns has changed through the lesson. Focus especially on question 6 +7 to guide discussion. (10 min.)

Step 5: For [PBL option]* students conduct PBL reflections ‘Know and Need to know.’ Then add artistic components to the ‘Drop of Seawater’ project. Use the PBL summary table to help formulate ideas, before adding them to your Drop of Seawater art.

Step 6: After this lesson, students should have a better understanding of: 1) how phytoplankton abundance might change with location, 2) relative abundances of different phytoplankton types, 3) relative scale of phytoplankton cell sizes.

*If not doing PBL option: to assess learning use Worksheet #1 questions 6-7-8** (10 min.)

**If Lesson 4 is the final lesson in the module for the class go to:

1. Applications_Discussion assessment Tasks(rough draft) * as final assessment tasks. Have students create poster presentations/written essays to elevate student thinking and their application to the global system. (*Can begin to meet NGSS standard(s) HS-ESS2-7, ESS3-5, ESS2-6).
2. Invisible Forest post-assessment

See Overview: ASSESSMENT OPTIONS for the Invisible Forest Module

Assessments

Assessment: How will I know they know……(How do we know they are learning?)

• • Worksheet 1 (Google Doc | Word Doc)
  • will collect students’ initial and final understanding of Lesson 4 — how information on phytoplankton from one sample can be expanded to understand global patterns.

• Overview: ASSESSMENT OPTIONS for the Invisible Forest Module

• • **If not doing PBL ‘Drop of Seawater’ and not continuing to Lesson 5: use Applications_Discussion assessment Tasks(rough draft) as presentations/written final assessment and Invisible Forest end of module growth Invisible Forest post-assessment
  • [PBL option] compare student art to ‘Drop of Seawater’ Teacher Key_example. (The components to each ‘Drop of Seawater’ will vary as they reflect learning based on the level of the course.)

Resources

• Introductory slides and video link
• Worksheet 1 (Google Doc | Word Doc) (including pre/post assessment questions) and Worksheet 1 _Teacher key (Google Doc | Word Doc)
• Dataset 1 (Google Doc | Word Doc) ,and Dataset 1_Teacher key (Google Doc | Word Doc)
• Dataset 2 (Google Doc | Word Doc), and Dataset 2_Teacher key (Google Doc | Word Doc)
• Dataset 3 (Google Doc | Word Doc), and Dataset 3_Teacher key (Google Doc | Word Doc)
• NCBI nucleotide database
• Applications_Discussion assessment Tasks(rough draft)
• Overview: ASSESSMENT OPTIONS for the Invisible Forest Module

Accommodations

Extensions

See DNA sequence identification activity using BLAST search

• Use BLAST* search for Dataset 2 activity (*this is a widely used public search tool, only recommended for small class sizes to avoid traffic jams in the data pipeline)

References

• Data source for “Data Set 1”, satellite data, (https://oceancolor.gsfc.nasa.gov/)
• Ocean Color Web, including teacher resources, images, videos.
• NASA Ocean Color teaching resources
• NASA Ocean Color MODIS platform outreach resources
• The Darwin project
• Atlantic Meridional Transect program