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Taxonomy and Dichotomous Keys

ESSENTIAL QUESTION:How can you use dichotomous keys to classify and identify organisms?

Key points:1. Plant parts (roots, stems, leaves, flowers, seeds)

are used to classify plants using dichotomous keys2. Animal structures (appendages, beaks, etc.) are

used to classify animals using dichotomous keys3. Use dichotomous keys to identify organisms

kingdom and domain, review the characteristics that divide organisms into domains and kingdoms

Taxonomy

• Taxonomy is the science of naming, describing and classifying organisms.

• It includes all plants, animals and microorganisms of the world.

• Using morphological, behavioral, genetic and biochemical observations, taxonomists identify, describe and arrange species into classifications.

Taxonomy

• Taxonomists provide unique names for species, labels that can help us find out more about them, and enable us to be sure that we are all talking about the same thing.

• Crash course video on taxonomy: https://www.youtube.com/watch?v=F38BmgPcZ_I

Classification

• Brain Pop!

Dichotomous Keys

7.11A examine organisms or their structures and use dichotomous keys for identification

What is a dichotomous key?

A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, and fish.

Keys consist of a series of choices that lead the user to the correct name of a given item.

"Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step.

Purpose of Keys

To classify organisms

But what if we find things we don't know

and we want to know what they are?

What’s my name !?

We use something’s

characteristics in a

similar way using…

Dichotomous keys use…

• Characteristics in order to distinguish one organism from another!

• Video: Crash Course

Here are creatures we don’t know!

Lets choose one

How to use a Dichotomous Key?

Choose only one creature at a time.

How to use a Dichotomous Key?

Read steps 1a and 1b

Decide which statement is true

How to use a Dichotomous Key?

1b is true

Then follow the directions after that step.

How to use a Dichotomous Key?

At choice 5, you make another dichotomous choice

How to use a Dichotomous Key?

5a is true

Keep going until you come to a step

that gives you the creature’s name.

How to use a Dichotomous Key?

6 a. The creature has one antennae Go to Step 7.

Choose a new creature and start at step 1a and 1b again. Continue until you find the creature’s name.

C

How to use a Dichotomous Key?

Where do you start Again?

Then, find the names of all the

creatures

Practice!• Now work with your table partner to complete

this page:

Homework for Practice:

More Practice Activities

Jelly Bean Dichotomous Key!

Insect “parts”:

• Abdomen –

• Antennae –

• Thorax –

Insect Dichotomous Key

• Students will work in groups of 2 and then 4.

• Each group of two students should get a single bag of bugs.

• It will be marked with a number and a letter (1A, for example)

• The other pair at their table should get the complementary bag so that the table of 4 has a complete set of bugs. (1B, for example)

Instructions:

• Make sure you have a class color copy of theInsect Letter Guide(1).

• You should also have black and white class copies of the Insect Dichotomous Key and, Scientific Name / Common Name Key. (2,3)

• Each pair should have each paper.

Instructions continued:

1 2 3

• Now you and your partner are ready to use the dichotomous key to identify the insects in your bag.

Next step:

• After you have identified your insects then share and compare your data with the other pair at your table.

• Be sure to put the correct bugs back into your bag!

Go through the insects and ID them using the key

• Next, students work as a group of four to answer the Analysis questions.

• In order to answer the analysis questions make sure to get an Insect Answer Key and a Scientific Name / Common Name Key.

Next Step - Analysis

Analysis Questions – can be worked on in your larger 4 person groups

Conclusion Questions are INDEPENDENT WORK!

Last Step: Complete the questions