1. Introduce the activity using a KWL chart.
Provide each student with a copy of the Marine Ecology Video Scavenger Hunt worksheet and divide them into groups of four. Give each group a large sheet of paper to create a KWL chart based on the key terms listed at the top of the worksheet. Ask groups to draw the “K” column of their chart and then discuss and write down what they Know about the key terms. Observe and facilitate student groups and then have them draw the “W” column on their chart. Ask them to write down what they Want to know about the key terms. Instruct them to list terms they are unfamiliar with or questions they might have. In small groups or as a whole class, address student questions.

2. Show students the four videos and have them complete the Video Scavenger Hunt worksheet.
Read aloud the directions for the worksheet. Instruct students to pay close attention to the ways in which species, populations, and communities of organisms are interdependent and interact with one another and with their environment. Then, for each video segment complete the following steps:

• As a class, have students use the Water Planet Mega Map, included in the World Physical MapMaker Kit, to geolocate the ecosystem in the video (Antarctic Ocean, Indian Ocean, Monterey Bay, California, United States, Everglades, Florida, United States).
• Introduce the video and focus student attention on the five key terms they will need to use in their description of the ecological concepts addressed in the video.
• Ask students to complete their worksheets individually as they watch the video and afterward review their responses as a group.
• Ask groups to draw the “L” column of their chart and then discuss and write what they Learned from watching the video.

3. Have a whole-class discussion about students’ observations and KWL charts.
After all the videos have been viewed, student worksheets are completed, and group discussions have concluded, follow up with a class discussion. Ask each group to report what they learned using what they have written in the “L” column of their charts. Ask if there are still things they want to know. Clarify any questions or misconceptions and address important ecological principles that students may have overlooked.

4. Conclude the activity and discuss how humans impact marine ecosystems.
Explain to students that, although the videos represent very different marine ecosystems, the ecological themes—especially interdependence and interactions—are similar and are an essential part of characterizing and supporting these diverse ecosystems. Ask students to discuss the ways humans interact with and impact marine ecosystems in the videos. Ask: Can you think of ways humans impact other marine ecosystems? Explain.

1. Introduce vocabulary terms related to ecological interactions and symbiosis.

Explain that in this activity students will use a series of videos, images, and scenarios to identify and discuss examples of ecological and symbiotic relationships in the ocean. Write the following terms on the board: competition, predation, symbiosis, mutualism, commensalism, and parasitism. Do not include the definitions yet. First, ask students to identify the root words and brainstorm what types of ecological and symbiotic relationships the terms describe. Then, review the definitions of the terms. Point out that the term symbiosis is an overarching term for mutualism, commensalism, and parasitism and that the ecological relationships predation and competition are not generally considered to be symbiotic.

• competition—when two or more organisms rely on the same environmental resource

• predation—behavior of one animal feeding on another

• symbiosis—the close relationship of two dissimilar organisms

• mutualism—a symbiotic relationship where both organisms benefit

• commensalism—a symbiotic relationship where one organism benefits and one does not benefit but is unharmed

• parasitism—a symbiotic relationship where one organism benefits and one is harmed

2. Build background about National Geographic Crittercam.
Explain to students that they will watch footage from a National Geographic project called Crittercam. Crittercam’s goal is to help researchers understand the day-to-day lives and ecological relationships of different species. Scientists fit wild animals with a GPS tracker and a combination video and audio recorder with environmental data instruments to measure such things as depth, temperature, and acceleration—which allow the study of animal behavior without interference by human observers. Ask students to think about the benefits of studying animal behavior and ecological interactions without interference by human observers.

3. Have students use a Crittercam video to identify ecological relationships.
Show students the National Geographic video “Fish Thieves Take Rare Seals’ Prey” (3.5 minutes), in which an endangered Hawaiian monk seal preys upon and competes for fish and invertebrates on the seafloor at 80 meters (262 feet) deep. Ask: What is the ecological relationship between the monk seal and the octopus/eel/trigger fish? (predator/prey)  Ask: What is the ecological relationship between the monk seal and the jacks/sharks? (competition) Ask students to again think about and discuss the benefits of studying animal behavior and ecological interactions without interference by human observers. Elicit from students that Crittercam allows researchers to examine the behavior and interactions of marine species that they normally would be unable to observe. 

4. Have students view videos to identify symbiotic relationships.
Show students the three videos of different marine species interactions. After each video, have the class identify and discuss the symbiotic relationships they observed.

• “Caribbean Cleaners” (2.5 minutes)—mutualism

• “Giving Fish a Bath” (5.5 minutes)—parasitism

• “Clownfish and Sea Anemone Partnership” (1.5 minutes)—mutualism

Ask: What type of symbiotic relationship was not shown in the videos? (commensalism)

5. Use a National Geographic image to explore commensalism and discuss the origins of Crittercam.
Display the image “lemon shark” in the resource carousel and have students observe it closely. Ask: Other than the shark, are there any other organisms you see? Elicit from students that the shark and the remoras, the smaller fish below the shark, have a symbiotic relationship called commensalism, where the remoras benefit from holding onto the shark, but neither species is harmed. Tell students that this commensal relationship is why Greg Marshall, marine biologist and filmmaker, invented Crittercam. In 1986, a shark approached him during a dive near Belize. Marshall noticed a remora clinging to a shark, and as he watched the shark disappear, it occurred to him that if he could put a camera in the place of the remora, he could see the shark's behavior unfold without disturbing the shark. Explain that with Crittercam, Marshall learned that remoras attach themselves to predatory fish like sharks for two reasons: a free ride and protection due to hanging onto a feared predator. The shark is not affected in the process since remoras eat only leftover food from the shark.

6. Have students read statements and identify types of ecological interactions.
Give each student a copy of the Symbiotic Interactions worksheet. Read aloud the directions. Tell them that they should be able to provide reasons for their choices. Discuss the answers as a class. Have students explain why they classified the different scenarios as one type of symbiosis and not the others. Ask: How do ecological relationships shape the marine ecosystem? Why is it important to identify and understand these relationships?

1. Review vocabulary.
Explain to students that they will work in small groups to create an imaginary marine ecosystem illustrating the various trophic levels, adaptations, symbiotic relationships, and niches of a community of marine organisms living in that ecosystem. Write the following vocabulary terms on the board and ask students to define them and give examples:

• abiotic and biotic factors
• food web
• adaptation, niche, habitat
• symbiosis: mutualism (both benefit); parasitism (one benefits/one harmed); commensalism (one benefits/one unharmed)
• trophic levels: producer (autotroph); primary/secondary/tertiary consumer (heterotroph); herbivore, carnivore, omnivore, decomposer, parasite, apex predator

2. Introduce the activity.

Divide students into small groups and distribute the two worksheets: Imaginary Marine Ecosystem Instructions & Organism Descriptions and Imaginary Marine Ecosystem Analysis. Also give each group markers and two pieces of butcher paper. Read aloud the directions. Clarify that students will create at least eight different organisms to inhabit their imaginary ecosystem. Six must be real marine organisms and live in the same real world ecosystem. The other two must be organisms that students invent. Use the worksheet to review what students should include for each organism, using the terrestrial example provided. Next, explain that students will create an imaginary ecosystem illustration. The illustration will include all eight organisms and the important abiotic components of the ecosystem, including water, sediment, rock, energy source, and other habitat features such as ocean floor features. Then, explain that students will create an imaginary ecosystem food web. Tell students to label each organism by name and trophic level and to use different colored arrows to represent each trophic level. Emphasize the importance of using arrows to show the proper flow of energy between organisms and trophic levels. If needed, refer to the two provided examples of rocky intertidal food web diagrams as examples. Finally, explain that students will answer the questions on the Imaginary Marine Ecosystem Analysis worksheet and present their ecosystems to the class.

3. Give small groups time to complete the activity.
Answer any questions students may have. In their small groups, give students 1 hour, 30 minutes to complete the project, which includes organism descriptions, an ecosystem drawing, a food web, and analysis questions. Remind them of the time periodically and make sure that they are making appropriate progress.

4. Have groups share their ecosystems and discuss them.
With approximately 20 minutes of class time remaining, ask groups to present and discuss their imaginary marine ecosystems to the rest of the class. Allow other students to ask questions about each ecosystem and their imaginary organisms. To wrap up the activity and assess student comprehension, ask students to discuss question #11 from the Imaginary Marine Ecosystem Analysis worksheet. Ask: How do ecological and symbiotic relationships shape your imaginary marine ecosystem? Why is it important to understand these relationships? Display each group’s work in the classroom and refer to them throughout the remainder of the unit.