By the time my students reach sixth grade, they have been practicing classifying objects by physical properties for YEARS. Shape, color, smell, texture, mass, density, magnetism, luster…We actively sort things into categories based on similar characteristics as a means of identification. However, without FAIL, when we begin learning about the classification of life, my students struggle to wrap their brain around the concept. I have been experimenting for several years with ways to increase understanding, and I feel like I have finally made some progress on teaching taxonomic classification.
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The first change I have made is extending this unit of information from three weeks to four weeks, ensuring my students have a firm grasp of the scientific vocabulary. Students must have knowledge of cell structure, methods of reproduction, and acquisition of nutrients to understand the most basic levels of classification- Domains and Kingdoms.
In Texas, 6th grade academics only focus on these two taxa, but I have found it impractical to expect students to understand the bigger picture without at least SOME exposure to the entire system. So while our focus is on the top two levels, our practice activities include learning about the other taxa as well.
Recalling Prior Knowledge
As I mentioned, most students have had some exposure to classifying matter based on physical properties for many years–even if they don’t realize it! During small group discussions, I always start with simple examples of ways we have classified things based on physical properties in the past, like relative density (sink or float?). This allows students to recall prior knowledge and come up with more examples of their own. Then we move into putting more complex groups into a taxonomic system.
For example, instead of immediately attempting to classify life, we first create a simple system to classify our school into different levels, from biggest to smallest group. Level 1 (domain) – Teachers, Staff, and Students. Level 2 (kingdom) – Subject (Teachers), Grade Levels (Teachers), Position (Staff), Grade Level (Students)… I like to see how far the students get with this before their heads start to explode!
Graphic organizers are extremely useful in helping students attain mastery of taxonomy. We use several during the unit. After trying quite a few different things, I finally think I have gotten the formula right. Here are three organizers I have found the most beneficial.
My students start with the basic, upside-down pyramid organizer early in the first week once we have covered the necessary vocabulary. This allows an introduction to the entire scientific classification system (not just the Domains and Kingdoms). They keep it in their science journal to reference throughout the unit.
It also provides an understanding of how the system works–from largest number of organisms to smallest and from broadest common characteristics to most specific. The version of this graphic organizer I recently created can be found here.
I will admit, this is an activity I didn’t plan on doing this year. It was one of those mornings I walked into class and tossed my lesson plan out the door. Lucky for me, because I was blown away by the student output for this activity! I highly recommend trying it out in your classroom. I wrote up the project sheet after the fact so I would have it for next year, but you can get the FREE instructions and rubric here!
All you need are some flashcards and paperclips to create this mobile, and it is way more stimulating than simply copying the information down into boxes! Students must choose an organism, then research the taxonomy, scientific name, and determine the following: eukaryotic or prokaryotic, single- or multi-cellular, autotrophic or heterotrophic, and the method of reproduction.
Faux Dichotomous Key
While I do think sixth grade is a bit too early to introduce a dichotomous key, they are most certainly capable of creating a system of categorization based on similar characteristics. (A rose by any other name…)
I use a color coded, mind map style graphic organizer as an example for students to create their own taxonomy. I find having a pre-made worksheet for this activity limits them and forces them to come up with one solution, when that may not be the case. I also tend to swap out the objects occasionally to see what works best, though I think I have finally settled on feathers. Leading me to the next suggestion for…
The previously mentioned graphic organizer is used to categorize feathers. I don’t know what it is exactly, but the students LOVE the feathers. Heck, I LOVE feathers. At the very least, it is a memorable manipulative to help student retention. I have had students come back from years past and tell me how much this activity helped them understand the concept as they advanced to more complex topics like real dichotomous keys.
The students work in teams of 2-3. Each team gets a random bag of feathers (that is actually carefully curated by me for simultaneous diversity and ease of classification). I show them the example of the faux dichotomous key and explain how to use it. Then they are free to organize the feathers in any logical system.
Bonus tip: You will have a few groups who get it quickly. If they finish too early, challenge them to create a different system.
I consider this my capstone for the unit. The grand finale! You may notice I do lots of projects…but only because my students have always responded so well to them.
For this particular project, students have “discovered” a new species, and they must document it for the scientific community. The new organism must be illustrated, given a scientific name (binomial nomenclature) and common name, and classified according to the taxonomic system. I encourage students to make sure their creation has SOME characteristics in common with another living thing so they have a basis for researching it’s taxonomy.
You can check out the entire project (and unit of activities!) here in my store.
Taxonomy is difficult to teach the first time students are introduced to the concept, but hopefully these resources and activity ideas will help increase your student comprehension and mastery!
NEXT: Thinking about a class pet? Make sure you’re ready!