Student Worksheet

Invertebrate Dichotomous Keys - Activity Instructions

When exploring outdoors in the bush, a park or down by the sea, knowing the common and scientific names of things requires you to have a guide. One type of guide that is frequently used are identification keys. Knowing how to use a key to identify plants, birds, reptiles, mammals, insects, fungi, fish or spiders is a way of unlocking the secrets to life on earth.

The use of keys to identify living things is a practical skill that comes in handy in a variety of different contexts. Some of these uses include identifying bugs that may be in the garden, types of fish species, determining appropriate plants for landscaping or training yourself to become a bird-watching enthusiast or 'twitcher'.

Kids are naturally curious and as we grow we depend on our curiosity to understand the world we live in to lead a full and interesting life. Scientists never stop asking questions and designing hypotheses to test their predictions. Ecologists are scientists who investigate what organisms live where, how many are present and why they live where they do.

This activity helps you learn how to use a key to identify living things. In particular, you will be using a dichotomous key. A dichotomous key provides pairs of identifying features that lead you to the correct name. Learning how to use a dichotomous key is a cool skill that increases your awareness of the world around you and your role in caring for the environment.

Safety advice: Conduct a risk assessment of the site. Examples of potential dangers outside: large trees with dead/dying limbs, stinging, biting insects, sunburn and dehydration. Remember, it’s always best to be prepared by having a phone and first aid kit handy.

Part A: Identifying Similarities And Differences In Living Things

Step 1.

With the help of an adult check out a safe location outside such as your backyard or nearby park where you can investigate a variety of living things. Ensure you have all the materials you need for this activity before heading out, including:

Backyard Dichotomous Key
Clear container such as a plastic tub or glass jar
Device capable of accessing internet OR device capable of taking photos
Invertebrates Key
Notebook
Pen/pencil
Small bucket
Small paint brush
Sweep net (optional)

Step 2.

Once you are settled in your outdoor space, spend some time using your senses to observe the living things in this outdoor space. For example, crush the leaves of different trees to identify if there is a distinct smell present in one but not the other; feel the texture of the bark of different trees to to see if it is flaky, rough, stringy or smooth; and observe the shape of bird beaks as fine and pointed for catching insects or narrow and hooked for nectar feeding.

Record your observations in your notebook.

Step 3.

Make up a name for each living thing you observe. The name you select should include its identification feature, such as ‘flaky bark tree’, ‘pointed beak black bird’ or ‘mint leaf bush’.

Step 4.

You can then take a few minutes to record a few sentences that describe the pros and cons of naming organisms based on your personal sensory experience of them.

Part B: Using A Dichotomous Key To Identify Garden Invertebrates

Step 1.

Read this text:

"The living world is vast and complex and there are an almost unimaginable number of organisms to name and organise. Each of us may make different observations about living things or our descriptions may not be easily understood across countries, languages and cultures.

The global scientific community classifies living things to help us order and organise the living world. We call this system of classification 'taxonomy'. So how do we fit living things into this classification system?

When we know the scientific name of the organism we are looking at, it is easy for us to find out how this species fits into the classification system. However, what happens when we don’t know the name of an organism? How can we find out its name, let alone how it is classified?

One way to identify an organism is to use a dichotomous key. Dichotomous keys are useful tools that help us organise things into identifiable groups by classifying things according to whether a particular characteristic is present or absent."

You’re now going to spend some time learning to use a dichotomous key.

Step 2.

Take a look at the Backyard Dichotomous Key. This key will help you to identify living things into Kingdoms, such as Animalia, Plantae or Fungi. Use the key to identify some of the plants and animals in your outdoor space.

Step 3.

You will now use a more complex key to identify invertebrates.

Still outside, spend some time searching for small invertebrates (animals without backbones) by using:

a small paint brush and clear container to carefully lift and sift through leaf litter
a living branch gathered in one hand to beat over a white tray or small bucket to catch invertebrates as they fall from the branch being beaten
a sweep net (if you have one) being brushed and swished through longer grasses and small shrubs.

Step 4.

Invertebrates that are trapped are to be kept alive in clear containers for observation with a magnifying glass if possible.

Step 5.

Use the CSIRO electronic key and Invertebrates Key to identify invertebrates. Note: If you have a device to access the CSIRO key while you are outdoors, take photos of the invertebrates you collect so you can identify them back at home.

Record names of the invertebrates in your notebook. Release your invertebrates back to where you found them.

Step 6.

Identify the dichotomous key you preferred to use, either electronic or paper.

What did you like about this key?
How do you think the key could be improved?

Part C: Invertebrate Profiling

Step 1.

Back at home, use your research and scientific communication skills to create a profile of one of the invertebrates in your notebook.

Your invertebrate profile should include a scientific drawing. Scientific drawings help you remember how to identify the invertebrate by its special features. It’s important to only draw what you see and use a pencil. Check the Scientific Drawing Guidelines if you need some drawing tips.

Invertebrate profile descriptors

Genus
Species (if known)
Common name (if known)
Where found/habitat
Main activity (what is it doing)
Interactions with other living things
Other observations

Taking Action

Get involved in a citizen science project. Citizen science projects allow people without scientific qualifications to work on science research projects by collecting data. Often this data collection involves identifying different organisms and recording what, where, how many and what they are doing. Check out the ClimateWatch app and get involved. ClimateWatch needs YOU! www.climatewatch.org.au

Invertebrate Dichotomous Keys (home learning)

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