Learning to Look: Taxonomy - How Do Scientists Classify Life?

What is taxonomy?

Taxonomy (tax-on-ah-mee) is the science of naming, defining, and sorting groups of living things based on their characteristics. Scientists use taxonomy to understand nature - by making observations about living things, scientists are able to group similar living things together - helping us understand how all living things are related.

Lets Practice Taxonomy!

While exploring, a scientist discovers a new room in their house - and it’s overrun with animals! The scientist has never seen these animals before, and has a lot of questions. Some of the animals look very similar to one another, but others look COMPLETELY different! The scientist could study each animal individually, but they have a bigger question they want to answer - how are all of these animals related to each other?

Eighteen stuffed animals in a pile

The scientist counts 18 animals, and is able to gather them all together in a group. The best way to figure out how the animals are related is to sort them into smaller groups, based on their similarities.

Be the Scientist

What similarities and differences do you see in the animals?
What categories could you use to sort the animals into smaller groups?
There are no right or wrong answers!


Making a list of similarities and differences

The scientist makes a list of similarities and differences in the animals. - Some of the animals are wearing clothes. - Some of the animals are different colors. - The animals have different body shapes: some are sitting, and some are lying down. - Some of the animals have different numbers of legs.

Sorting by Color

There are a lot of different ways these animals could be sorted into smaller groups, so the scientist goes down the list. After thinking hard, the scientist decides not to sort the animals based off if they’re wearing clothes. After all, the scientist sometimes wears clothes and sometimes doesn’t, but that doesn’t change the type of animal they are! The scientist tries to sort the animals by color.

Blue and Purple

Three blue and purple stuffed animals


Stuffed bear, puffin, and gorilla with black fur


Seven toy stuffed animals with white fur


Five toy stuffed animals with brown fur

Sorting by Body Type

Sorting by color is okay, but it isn’t perfect. Some of the animals that look very similar to each other (like the black bear and brown bear) are in completely different groups! It’s also hard to keep track of four different groups at once. The scientist decides to split the main group in two, by their body type - whether they’re sitting up or lying down.


Many stuffed animals sitting together

Lying Down

Five stuffed animals lying down

Sorting Animals by Number of Legs

Sorting the animals by body type works okay, too. Now the bears are in the same group - but the scientist has a new problem. The spotted dogs look almost identical, but now they’re in two different groups! That leaves one last option - sorting the animals by their number of legs.

4 Legs

Many stuffed animals, each with 4 legs

More Than 4 Legs

Two toy stuffed bugs

Sorting by Feathers and Fur

Now that the animals are in two groups, they can be split even further. The scientist knows the other categories they tried (color and body position) won’t work for the same reasons as before - so they need to come up with NEW categories for sorting. Be the Scientist: What NEW categories can you come up with to sort the animals? Think about features of the animal’s body. Is it covered in fur, feathers, or scales? What type of teeth does the animal have? Does it have hooves? Antlers? The scientist decides to split the animals once more - into a group with feathers, and a group with fur.


Toy stuffed puffin


Stuffed animals with fur

Making a Cladogram

By constantly splitting the animals into smaller and smaller groups, the scientist starts to see how the animals are related. An animal with fur is closely related to an animal with feathers, because they both have 4 legs. The scientist wants to keep track of their discoveries, so as they sort the rest of the animals, they make a chart.

Charts like these are called “cladograms” (clah-doh-grams), and they help scientists keep track of how all life is related.

Be the Scientist: Only some of the chart is filled out. Can you figure out the traits the scientist used to sort the rest of the animals?

Download the stuffed animal cladogram - blank
Download the stuffed animal cladogram - accessible/descriptive
Download the suggested answers

Now it’s your turn!

Look around your house for something to sort - stuffed animals, candy, buttons, marbles, or anything else. Make observations about the similarities and differences in the objects - then sort! If it helps, make a chart to show how you sorted the objects. You'll need paper and a pencil or something else to write with.

Learn More

Watch scientists at the Chicago Field Museum sort candy with Emily Graslie from TheBrainScoop!

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