Dichotomous Keys and Classification

Dichotomous Keys and Classification

Classifying organisms one step at a time

What is a dichotomous key?

"Dichotomous" means divided in two parts. These help determine what an organism is through a series of choices that lead you to the correct answer

Multiple Choice

The word "dichotomous" means...

• divided into two parts

• not living

• two cots for me to sleep on

Let's try one!

• Look at the images of the insects.

• Start on question 1.

• Depending on the answer, go where the question tells you to go.

• Stop when your organism has been identified.

Example one...

What is example A?

Are the wings covered by an exoskeleton? That's a skeleton on the outside.

Multiple Choice

Is there an exoskeleton on the outside of the wings?

• No, go to step 3

• Yes, go to step 2.

Keep going until you know what the organism is.

Look at the wings. Are they pointed out from the body or are they toward the rear of the body?

Multiple Choice

Look at the wings. Are they towards the outside of the body or are they on the back of the body?

• outside of the body

• back towards the body

Multiple Choice

What organism is this?

• bee

• dragonfly

Look at organism B...

Are the wings covered by an exoskeleton?

Multiple Choice

Is there an exoskeleton on the outside of the wings?

• Yes, go to step 2.

• No, go to step 3.

The wings are hard so yes to the exoskeleton.

Go to question 2. Look at the shape. Is it round or long?

Multiple Choice

Is the body shape round or elongated?

• round

• elongated

Multiple Choice

What organism is this?

• firefly

• ladybug

Look at organism C...

Are the wings covered by an exoskeleton?

Multiple Choice

Is there an exoskeleton on the outside of the wings?

• Yes, go to step 2.

• No, go to step 3.

Keep going until you know what the organism is.

Look at the wings. Are they pointed out from the body or are they toward the rear of the body?

Multiple Choice

Look at the wings. Are they towards the outside of the body or are they on the back of the body?

• outside of the body

• back towards the body

Multiple Choice

What organism is this?

• firefly

• dragonfly