Dichotomous Keys Huh? Hippopotamus?? Click here:

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

Dichotomous means “divided into 2 parts” I think I am starting to get it – can you give me an example? 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.

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: Long, cylindrical objects Short, non- cylindrical objects plastic non-plastic green & grey blue & clear black & silver silver ---- highlighter ---- pen ---- pencil ---- pencil sharpener ---- paperclip

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

1AObject has only straight lines, go to 2 1BObject has curved line, go to 4 2AColor is blue-- Azul calamus 2BColor is not blue, go to 3 3AObject has four equal sides-- Quadratis rufus 3B Opposite sides of object are equal-- Rectangulo crudus 4AObject has one continuous curving line, go to 5 4BObject has curved and straight lines-- Azul undo 5AObject is red-- Ovalado rufus 5BObject is green-- Orbis crudus LET’S TRY IT TOGETHER WITH THIS DICHOTOMOUS KEY EXAMPLE: 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, 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 identify the rest of these objects

Don’t look at the answers until you try!!

Did you get them right? Ovalado rufus Orbis crudus Azul calamusQuadratis rufus Azul undo I did! Did you?

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 before checking the answers! A B C EDF G H

Good job! Tomorrow you will find out if you got them all right! See ya, bye!