This resource is a compilation of text, videos, and other elements to create a scaffolded 5E learning experience for students. This is meant for Tier I instruction under the Response to Intervention (RtI) model for grade 7 science TEKS (7)(11)(A), specifically, dichotomous keys.
Be sure to check for prerequisite knowledge and skills as well as differentiation needs by reviewing the entire resource and the related items before assigning it to or working through it with your students.
This resource can be used for instruction in a variety of ways.
• Use with a single computer and projector; this can be delivered in a traditional classroom.
• Use with a combination of individual student computers and teacher computer and projector (in either a computer lab or other 1:1 environment).
• Assign the resource to students as work to do outside of the school day as part of a "flipped classroom" to allow application, practice, and additional support during the school day.
• Use with students as tutorials.
• Share with parents to inform them about what their child is learning in school.
• Use with students who are unable to participate in the traditional classroom environment.
Students are intrigued by the setup of a murder-mystery experience. This is meant to heighten students' curiosity and engagement. By getting students engaged in something that seems like entertainment, they may make better connections to the content.
Students view a video containing the results of the suspects' interviews with police. Students use this information and a dichotomous key to determine who is the perpetrator of the crime.
Insert another dichotomous key experience for students who seem to struggle with the murder-mystery key. Multiple experiences that seem nonscientific will help students better understand how they work. Once students understand how these keys work, then they can apply their understanding to a more scientific use of the tool.
The Explain phase reveals to students that they were using a dichotomous key for the murder mystery and then illustrates a more scientific application for the student using a video. While dichotomous keys are generally used for plants and animals, they could conceivably be used for rocks, biomes, and other scientific areas.
This is an important place to mention the specific verb that's used in the 7(11)(A). The student expectation reads, "The student is expected to examine organisms or their structures such as insects or leaves and use dichotomous keys for identification." The key word here is use. Students are expected to use a given dichotomous key to come to a given conclusion. Given the specific verb in the student expectation, having students create their own dichotomous keys may not be a valuable use of class time and may actually steal time away from practicing the skill students are expected to master.
Allowing students other experiences with dichotomous keys for plants and animals is beneficial here. The student expectation uses the term "such as," meaning that it is wise to expose students to dichotomous keys for organisms other than insects and plants. Varying the format of key is helpful for students as well so that they become comfortable with the different types of keys (flow chart, table, etc.).
The Elaborate phase gives students an opportunity to practice using a key that uses photos. There is no chart, and the experience is largely visual. This activity more appropriately mimics how scientists determine species in the field. (The leaf exercise answers are: Sassafras, Japanese maple, and Douglas fir.)