I am ashamed to admit I spent a good portion of my teaching career looking for good dichotomous keys for my students. I asked veteran teachers who would always claim to have an abundance only to disappoint me with bad runoff copies that contained vocabulary neither my native or ELL students could understand . I scoured the internet looking for good dichotomous keys my students could easily understand while exposing them to new organisms. I never found what I wanted.
I finally decided to take matters into my own hands and create my own dichotomous keys. After deciding which organisms I wanted to cover I set off to write the key itself. It took a lot of time, but I was very happy with the results. The first dichotomous key I created covered both bacteria domains, the four kingdoms and had viruses thrown in. It was a great way for me to assess my students understanding of the unique characteristics of those groups and their ability to classify. I thought about how I would present the organisms,
I decided against photocopies due to details often being muddied. I do not work in the richest school district so making class sets of color copies was not feasible either. I decided on presenting the organisms in a power point. The students could log into Schoology and then use their laptops, tablet, or cell phones to access the images. I did print out the dichotomous keys and answer documents.
The power point presentation was a great success! I paired the students up and watched them look at the pictures, read little notes and go through the dichotomous key to identify the organisms and viruses. I could listen to the students debate, about what they thought the answers were and redirect them if they were too far off. I could see what needed to be reviewed and what content my class had mastered.
This led me to creating a second Electronic dichotomous key dedicated to the flora of the Chihuahua desert. I have run across keys with plants that live further north or more humid climates compared to our desert. Although I like to expose my students to environments and creatures outside of our area, it is also important that they learn about their immediate surroundings as well. The next dichotomous key was based on desert plants. I was shocked to see how surprised my students were to see how many flowers our desert has. I had a few students come to class after a weekend to tell me now they noticed that El Paso does have a lot of plants and they remembered the names.
You can purchase these lessons at the following links:
Classifying Organisms Dichotomous Key
Desert Plants Dichotomous Key