LESSON 7: SEAFOOD AND PHYTOPLANKTON
Understanding Goals 
Phytoplankton are marine organisms that make oxygen and food in the ocean using sunlight. 
Phytoplankton provide most of the oxygen in the ocean and as much as half of the oxygen in the air. 
Many marine organisms eat phytoplankton; hence, these marine organisms would not be able to live without phytoplankton. 
Therefore, the phytoplankton are very important in the supply of seafood for humans. 
Small things – even things that are invisible to the naked eye, such as phytoplankton – have a large effect in large numbers. National Science Standards Life Science K‐4 Characteristics of Organisms (phytoplankton in particular) Organisms and Environments 5‐8 Populations and Ecosystems Vocabulary phytoplankton, photosynthesis Advance Preparation Be ready to play YouTube user zackrz7’s video at http://www.youtube.com/watch?v=7ahvSxpIh0M or videos/DVDs/tapes of sounds of waves. Print the pictures (see materials) or have them downloaded onto a computer. Be ready to play YouTube user youngesterTV’s video http://www.youtube.com/watch?v=JQYKa5AofQ8, which is a video clip of phytoplankton Healthy Ocean, Healthy Humans
Making Connections between the Ocean and Humans
30
Materials Pictures of phytoplankton available from NASA at http://www.mapwatch.com/news‐blog/2006/03/marine‐phytoplankton.html (from space); Australian Museum’s Beyond the Reef Project at http://amonline.net.au/exhibitions/beyond/phytoplnkton/index.htm (microscopic). Picture of kelp forest available from Stef Maruch at: http://www.flickr.com/photos/79257269@N00/1228333269 (kelp forest) A teaspoon Lesson Plan Part 1A (5 minutes) If the previous lesson (Lesson 6) was not taught, do part 1B instead. Listen to the sounds of waves. Discuss homework questions from previous class. Part 1B (10 min) Have students watch the ocean and listen to its waves for a few. Gather reactions. How do they feel after listening to the waves and watching the ocean? Part 2 (about 15 minutes) If previous lesson was taught: Last time, we learned that many different types of people depend on the ocean for their income and we considered the life story of canned tuna in particular. Today, we’re going to consider the life stories of the fish themselves before they’re caught and killed by humans for us to eat. Start from here if previous lesson was not taught: Ask: What do you think the fish and other marine organisms need in order to live? What do they eat? Think pair‐share for a minute and then gather ideas. Then show them the youtube clip of phytoplankton at (see materials). Ask students to consider why the phytoplankton are important as they watch the clip. Also show students the pictures of phytoplankton (see materials). One is taken from outer space (zooming out) and the other is a picture in the microscope (zooming in). Part 3 (15‐20 min) Have students think for a minute and reflect on what they saw. Then have students consider the following questions: 1 Why are phytoplankton important? Healthy Ocean, Healthy Humans
Making Connections between the Ocean and Humans
31
2
How can they be so important, but so small that we can’t even see them with our naked eyes? 3
What might happen if the phytoplankton disappeared? How would that affect the supply of seafood? Have students think pair‐share for 10 minutes and then have a whole‐class discussion for another 5‐10 minutes. If students are not able to answer question 2, demonstrate the idea that small things can have large effects when there are MANY of them, by doing the following: Have one student tap his/her pencil or pen on the desk. Then have two more students do the same…and then 3 more…and then 4 more…and then everyone else. Then stop. Ask students what they noticed about the noise level, and relate this to the case of phytoplankton. [it started out soft…but when everybody started tapping at the same time, the noise increased a lot….Even though phytoplankton is very small, there’s LOTS and LOTS and LOTS of them. Small things add up.] Also mention that a teaspoon of water from the ocean (have a teaspoon with you) can contain as many as a million phytoplankton organisms.” Reflection / Homework Questions Answer the following questions: 1 What are phytoplankton? Why are they important? 2
What would happen if the phytoplankton disappeared? Explain. Follow the format: If the phytoplankton disappeared, then _______________because _______________. Healthy Ocean, Healthy Humans
Making Connections between the Ocean and Humans
32