Most often, they are used to identify plant and animal species, although it can be used to classify any object that can be identified by a set of observable characteristics. It can be done in both a graphical (as a branching flowchart or written format - series of paired statements organized sequentially). the number of legs, weight, height, etc.) factors are considered. physical attributes such as how the organism looks, what color it is, etc.) and quantitative (i.e. When creating a dichotomous key, both qualitative (i.e. The further you divide the key, the more you learn about the specimen you are trying to identify. By correctly selecting the right choice at each stage, the user will be able to identify the name of the organism at the end. “Dichotomous” means divided into two parts, hence the dichotomous keys always present two choices based on the key characteristics of the organism in each step. Simply put, it is a method used to identify a species by answering a series of questions based on contrasting features (eg: physical characteristics) that have two possible outcomes. It’s the most commonly used form of classification or type of identification key used in biology as it simplifies identifying unknown organisms. people, animals, plants, bacteria, etc.) into specific categories based on their characteristics. Students and professionals use the dichotomous key to identify and classify objects (i.e. Download them as PNGs, JPEGs, SVGs or PDFs for publishing, printing, and sharing. Some examples are provided in the dichotomous key examples section you can use any template to start your project right away. In this simple guide, we will explain what is a dichotomous key and how to create one. It helps identify organisms by directing the user to look at the known organisms. With new species being discovered every day, it’s important to have techniques in place to identify and classify them. Create a dichotomous key based on the pasta you have and let students identify the pasta types using the key.Įxample key using macaroni, penne, farfalle, spaghetti and fettuccini.ġa: Pasta is hollow………………………………….Go to #2ġb: Pasta is solid…………………………………….Go to #3Ģa: Pasta is smooth and curved…………….MacaroniĢb: Pasta is long and straight………………….Penneģa: Pasta is shaped like a bow-tie………….Farfalleģb: Pasta is long and straight………………….Go to #4Ĥa: Pasta is round and thin…………………….SpaghettiĤb: Pasta is flat……………………………………….Fettucciniīookish Ways has an EXCELLENT starter pack of free, simple dichotomous key activity worksheets to help guide students if you don’t have the time to come up with your own.In the field of biology, classification plays a major role. Sample Lab: Gather up 4-6 different types of uncooked pasta. I recommend using something like pasta, buttons or feathers as a starting point, but honestly, just about anything will do. Start with something familiar.ĭepending on the skill level of your students, you may need to practice working through keys using a small sample of familiar objects with easily identifiable differences. It sounds confusing, but it really isn’t once you get the hang of it. They can be used to identify rocks, plants, trees, birds, reptiles and mammals.ĭichotomous keys are set up in a two question format, leading users through a set of choices designed to help them correctly identify the object of their inquisition. What IS a dichotomous key?Ī dichotomous key is a system used by scientists to identify different parts of the natural world. Not to toot my own horn or anything (toot, toot). Anyone can pull off Science + Math, but building content rich dichotomous key activities fused with trees, fish and art? That takes real finesse. But by far, my favorite combination is Science + Art as I find it to be a refreshing fusion. I try to find cross curricular opportunities when possible with ALL other subjects. Teaching dichotomous keys to students can be a dry topic but it doesn’t have to be! You may not have noticed this about me…but I love science AND art.
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