Activity 2: Dispersing on the Currents
Marine » Unit 1: Riding the Currents » Activity 2: Dispersing on the Currents
Materials & Setup
- Coral Reefs: Their Health, Our Wealth video, cued up to the segment on coral reproduction. (This is a relatively short video, so fast-forward with the picture showing until you start to see close-ups of corals. This is the beginning of the section on coral biology and habitat. You may choose to show this short segment of a couple minutes or begin where the narrator says, “Like all other animals, corals must produce new individuals to make sure their populations survive.” The six-minute reproductive segment ends when the narrator begins to talk about causes of death.)
- VCR
- “Map of Pacific Ocean Currents” acetate (master, p. 38)
- “Known and Estimated Numbers of Inshore Fish Species by Area and Likely Routes of Colonization” acetate (master, p. 39)
- Overhead projector and screen
For each of five student groups
- “Map of Pacific Ocean Currents” (master, p. 38)
- “Known and Estimated Numbers of Inshore Fish Species by Area and Likely Routes of Colonization” acetate (master, p. 39)
- One “Current Conundrums” card (master, p. 40)
For each student
- Student Page “Marine Life on the Move” (pp. 41-43)
Instructions
1) Display the “Map of Pacific Ocean Currents” acetate. Ask students to look at the currents depicted on this map and speculate about where most Hawaiian marine life originally came from. Note that ocean currents in the Pacific do not generally favor the dispersal of marine life from west to east, yet most of the marine life in the Hawaiian Islands seems to have originated in the western Pacific.
2) Lead a class discussion using the series of questions in the Teacher Background “Marine Life Reproduction and Dispersal” (pp. 31-33). During this class discussion, you will show the segment of Coral Reefs: Their Health, Our Wealth on coral reproduction. The discussion will cover the following points:
- Common reproductive strategies among marine animals, and
- How those reproductive strategies have allowed dispersal among islands in the Pacific.
3) After this discussion, divide the class into five groups. Give each group the “Map of Pacific Ocean Currents” and “Known and Estimated Numbers of Inshore Fish Species by Area and Likely Routes of Colonization” map, along with one of the five “Current Conundrums” cards.
4) Have groups work together to form a hypothesis in response to the question on the card.
5) Bring the class back together and have each group share its “Current Conundrum,” hypothesis, and reasoning. Use the Teacher Version of “Current Conundrums” (p. 34) to help groups fine-tune their responses if necessary.
6) As homework, assign the Student Page “Marine Life on the Move.”
Journal Ideas
- Would you say that planktonic larvae navigate the currents? Why or why not?
- Write a first-person narrative about the life of a coral polyp, incorporating the stages of development and the process of dispersal.
- Compare the process of planktonic dispersal through which much Hawaiian marine life arrived here with the settlement of the Hawaiian Islands by Polynesian voyagers.
Assessment Tools
- Participation in group work and class discussion
- Group responses to “Current Conundrums” (teacher version, p. 34)
- Student Page “Marine Life on the Move” (teacher version, pp. 35-37)