STUDENT INSTRUCTIONS

      Work together in informal groups of 3-5 in the classroom on Figures 4A, 4B, and 4C. As you work to understand these Figures make sure that you follow the Step One - Step Two procedure we have practiced in class.

      Figure 4A shows changes in turtle grass over 10 years in Florida Bay by comparing the biomass in 1984 and 1994. After you understand the data, imagine snorkeling over these seagrass beds. What do you think they looked like in 1994 compared to 1984? What change would you actually see? Also, how do you think the scientists got these data - what kind of measurements did they make and how might they have gone about getting this information?

      The *s in Figure 4A indicate locations where the difference between the 2 years is significant. What do scientists mean when they say that a difference is "significant"? What do the vertical lines at the top of the histogram indicate?

      The next step is to use what you've learned from Figures 4B and 4C to explain why turtle grass biomass declined from 1984 to 1994. Figure 4B is from Sarasota Bay Thallasia (turtle grass) beds off the west coat of Florida, and 4C from eelgrass (another type of seagrass) beds off Cape Cod, MA. Study 4B and 4C to understand the information they provide.

      Now apply the findings from Figures 4B and 4C to 4A. If you were asked to propose why seagrasses were declining in Florida Bay based on the findings from Sarasota and Cape Cod, what would you say? Is it valid to use information from one site and apply it to another? How would you assess the validity of doing that in this case? What kind of information would you like to know?