Dichotomous Keys

Huh? Hippopotamus?? Dichotomous Keys Huh??? Listen to the pronunciation.

Okay, now I can pronounce it, but what is it? ?

Dichotomous means “divided into 2 parts.” A dichotomous key is used to find the identity of something by making a series of choices. At each step, there are always TWO choices. I think I am starting to get it – can you give me an example?

Okay; let’s make a dichotomous key to identify these familiar objects:

This diagram shows how we can group the items according to similar characteristics:

This is how the same information would be shown in a key:

LET’S TRY IT TOGETHER WITH THIS DICHOTOMOUS KEY EXAMPLE: 1 3 5 2 4 Let’s identify Object #2: The first choice is whether the object has only straight lines or at least some curved lines. Since it has no straight lines at all, I go to step 4. Step 4 tells us that if there is only one continuous curving line, go to 5. Step 5 has to do with color. Since the Object is green, it must be an Orbis crudus. Now you try to identify the rest of these objects.

Did you get them right? Ovalado rufus Orbis crudus Azul calamus Quadratis rufus Azul undo

Now you try it! Use the dichotomous key to classify these Norns: Norns are a very rare and actually imaginary animal that belong to the genus Norno. There are 8 different species of Norno, generally located in specific regions of the world Use the key to identify the Norns below. Write the names in your Journal C B A G D E F H

Check your answers! YAy Yay, me! I did it!

Good job!

Dichotomous Keys