Activity 8: Teaching TipsUsing Blackline Master Ecology 8.4: The Structure of a Leaf, ask the students where gas exchange is possible. Also ask them to explain their response. Connect their experimental results with the structure of the leaf. Have them figure out what part of the leaf should not be coated with the petroleum jelly to allow carbon dioxide to get to the leaf. Draw on the board. Then discuss the oxygen cycle by pointing out what process is found on the north; on the south; on the west; and on the east. Have the students note the direction of the arrows. Is it clockwise or counterclockwise? (Clockwise) The oxygen cycle is available as Blackline Master 8.1. The following questions can be used to assess the students’ understanding of the oxygen cycle:1. Give one similarity between the materials that are found on the north and south axes of the oxygen cycle. (They are both products of a process; they are both gases) 2. Give one difference between the materials that are found on the north and south axes of the oxygen cycle. (Oxygen is given off in photosynthesis while carbon dioxide is used in photosynthesis; carbon dioxide is given off in respiration while oxygen is used in respiration.) 3. Give one similarity between the processes that are found on the west and east axes of the oxygen cycle. (Photosynthesis and respiration are life processes) 4. Give one difference between the processes that are found on the west and east axes of the oxygen cycle. (Photosynthesis is used only by the plants while respiration is a process used by both plants and animals, including decomposers) 5. Explain why this is a cycle. (Photosynthesis releases oxygen that is used in respiration. Respiration then releases carbon dioxide that is used in photosynthesis and in the process produces oxygen. Oxygen again is taken in for respiration to occur, and the cycle keeps going.) With the overwhelming contributions to the atmospheric carbon dioxide by animal respiration, CO2 from the water, burning, and plant respiration, you would expect the atmospheric CO2 to be very high. This is not the case since the CO2 is used by the photosynthesizers and is absorbed by the oceans forming dissolved CO2 in the process. Atmospheric CO2 makes up only about 0.03% of the atmosphere. The carbon available in the ocean is fifty times that found in the atmosphere. The carbon cycle is available as Blackline Masters 8.2 and Blackline Masters 8.3. This is the perfect time to ask the students, in their groups, to discuss what they learned in this activity. After a 3-minute discussion within their groups, have a class discussion where all the groups are expected to give one concept that they understood from this specific activity.After the class discussion, remind the students that these concepts are to be included in their Chapter Challenge of making a booklet addressing or focusing on one environmental/ecological issue. Assign Inquiring Further as homework. Specify that students are to access the Internet for this endeavor. Require them to cite at least three web sites as their sources. |