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:
- 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).
- Invisible Forest post-assessment
See Overview: ASSESSMENT OPTIONS for the Invisible Forest Module