Biogeochemical Cycles Performance Task
Lesson 17 of 23
Objective: Students will connect the themes of the biogeochemical cycles using a graphic organizer.
Ask students, “Based on your understanding of the carbon cycle, predict what might happen if large areas of rain forest continue to be cleared.”
This question is a good way to review the content covered the previous lesson, the carbon, nitrogen and phosphorus cycles because it allows students to make a prediction based on information already taught. Listen for students’ demonstration of an ability to make reasonable predictions based on factual evidence from the prior lesson.
Allow 3-4 students to share their responses and encourage them to defend their predictions, citing facts they have learned from the content. This type of discourse helps students practice the literacy skill of defending their opinions citing facts. Listen to the students’ responses and redirect students’ thinking as needed to ensure that correct reasoning and responses are identified. Facilitate academic discourse by students using the academic discourse sentence prompts as a guide.
Explain that the activity today involves a Biogeochemical cycle performance task that is intended to help students review for a summative assessment on biogeochemical cycles.
Before giving instructions for the assignment, briefly review each of the biogeochemical cycles. Guide this discussion by posing questions to students:
- What similarities exist between the carbon, water and nitrogen cycles?
- What role do decomposers play in the nitrogen cycle?
- How is transpiration like evaporation?
- How do organisms get needed nitrogen?
- How is phosphorus released into the environment?
After providing a summary of all the biogeochemical cycles, display the performance task instructions and explain the steps of the task. Inform students that the task is comprised of four smaller tasks:
- Identification of a set of terms as biotic or abiotic.
- Identification of the terms into one of the biogeochemical cycle categories.
- Graphic organization of the terms in a manner that shows the categorization of the terms.
- Constructed response to a set of questions related to the biogeochemical cycles.
Select a term from the term list and model the activity as outlined in the instructions. Perform a “think-aloud” so that students are able to see and hear how you problem-solve to determine the correct association of the term with a biogeopchemical cycle. When conducting a think-aloud, make sure you make no assumptions about what students know or don't know that could lead to short-cutting the verbal explanations that allow students to see how you arrive at the correct determination. For example:
- Identify the term as biotic or abiotic.
- Identify to which cycle it can be assigned.
- Color the term cut-out based on the cycle color code indicated in the instructions.
- Place the term in the appropriate group on construction paper, using an organization of your choice.
Distribute hard copies of the instructions and a set of terms to each small group. Make sure that scissors, glue stick, construction paper, markers and colored pencils are on the desks before class begins. This alleviates the needs for a lot of student movement once instruction begins. For large classes, this is particularly important because the movement can be a distraction and a source of “wasted” instructional time. Note: To help cut down on the need for movement, I stock plastic pencil boxes with these supplies and keep them on the desks at all times for students’ use.
Instruct students to work in groups of two to complete the assignment. Explain that students will begin by cutting the page of terms in two equal sets of terms. Because there are six columns of terms on the page, students will be able to divide the work equally which allow both to work on the same tasks, practicing the same skills.
In advance of the task, determine if you will assign students to ability based groups or if you will allow students to self-select. Be sure that the student needs within the class drive the decision regarding how you will assign students to groups.
Direct each member of the group to work independently to complete steps 1 and 2, and then work together to organize all the completed parts on the same paper for step 3. Instruct students to work with their assigned partner to answer the constructed response questions in part 4 of the assignment.
As students are working, walk around to observe and listen for correct and incorrect reasoning as students work to complete the task. When incorrect reasoning is noted, prompt the student to reevaluate his thinking by using inquiry-based questioning. For example, “I see you categorized sediment and rocks with the carbon cycle. Can you tell me what role sediment and rocks play in the carbon cycle?
Display a timer using a LCD projector so that students will be able to self-monitor their progress. Instruct groups to submit the completed assignment when done. The student work that is attached indicates that students were able to make the correct associations between the terms and the cycles.
Use the remaining time to review a few of the constructed responses that students submit and ask students if they have any lingering questions about the content. The student work that is attached shows that students were able to give correct responses to the constructed response questions.
Provide explanations for any incorrect student responses that arise and clarify any misconceptions that you hear. Remind students that the summative assessment will be administered the next time the class meets. Encourage them to study and use all the resources that you have made available to assist them outside of class.