Dichotomous Keys

By: Joshua Alexander and Charity Oduwegwu

Have you ever spotted an animal (or a tree, or flower) in Rockland, but didn't know what it was? You could probably see some of its features that make it unique from other animals, but you just were not able to identify it. With a dichotomous key, you can easily classify organisms and even nonliving things, and have a fun time exploring the county!

Safety

• If you are venturing throughout the county, make sure you are accompanied with an adult.

• Wear a mask if you're outside and near other people.

• Don't touch or get too close to any animals, as they could have a disease, they could hurt you, or they could be scared of you!

Video

The video explains what a dichotomous key is, and how you can use two model keys! The slideshow from the video and the model keys can be found in "Links to Resources."

Links to Resources

• Slideshow (the slideshow from the video)

• Dichotomous Keys (you can also look at the images of our keys below)

Make Your Own Key!

After seeing the two dichotomous keys for mammals and birds, you can try and make your own, using the materials list from above! Remember, the best features to use are features that make something unique, and do not change over some course of time. Your key can be as big or as small as you want. Do some research of flowers, trees, or animals that are commonly found in Rockland County, using a website like iNaturalist, and some research on characteristics of each thing on your key. You can even explore the county using your key, working to classify and identify as many animals as possible! Be sure to follow the safety precautions above if you are going outside and exploring. Use the procedure below to help you make your own key.

Procedure

1. Select the group of organisms that will be the focus of your key. Examples include mammals, reptiles, birds, or trees.

2. Research a specific number of organisms in that group to include in your key. The two example keys had 7 of each type of organism. Your key can have more or less than 7, depending on how you big you want it to be,

3. Identify some characteristics for the key. For example, if you did mammals, some features you may include the color of their hair/fur and if they have fur/hair at all.

4. Continue identifying and recording characteristics until you can make a full key. Each step must help in the identification and classification process in some way.

5. When you have finally assembled the key, make sure it works by testing it on some organisms. Are you able to follow the key and successfully identify it?

Citations

Dichotomous Key. (2019). Retrieved March 31, 2021, from https://oregonstate.edu/trees/dichotomous_key.html#:~:text=A%20dichotomous%20key%20is%20a,%22divided%20into%20two%20parts%22.