Linnaean Classification

Discussion Point – Linnaean Classification

This discussion point links to Years 5, 6 and 7 ‘Science’. These curriculum links are listed at the bottom of the page.

Banks, Parkinson and Solander were all on board HMB Endeavour and were part of the team collecting and recording what they saw. In many cases they were the first Europeans to see and record new species of flora and fauna. Some of the specimens from the Endeavour voyage can still be seen in museums around the world.

How would you record and classify a new specimen?

Step 1: Draw/paint it

These days if we see something that we have never seen before, we would take a photo. In HMB Endeavour’s case the equivalent action was to draw a picture, which is a much slower process.

Sydney Parkinson was the most prolific artist on board HMB Endeavour. He drew and painted landscapes, people and specimens. He also wrote notes and detailed labels on each piece. These annotations were added to by Banks, who had a greater natural science background. 

Parkinson’s skill with watercolours was very important on HMB Endeavour. He was able to record the colour of plant and aquatic specimens, which was the one of the first things to fade. Parkinson’s watercolours recorded what the specimen looked like just after collection, which gave a lot of important information to the scientists. 

Step 2: Make notes

When you find something new, it is very important to make notes about it and not just record its appearance (via a photo or drawing). These notes are a way to record things that you would not be able to tell from the picture alone.

These notes would include:

• when and where you found the specimen
• the specific type of environment the specimen was found in
• observations of the specimen’s appearance that are hard to record: colour (not all pictures were colour and a specimen’s colour was often difficult to represent accurately), texture, markings, etc 
• behaviour (if it was an animal).

Step 3: Basic classification 

If you find something unknown, you generally try to identify it in some way. Your brain does this for you all the time. If you see something unknown, you think about what you have seen before that looks familiar. For example, you might see an insect that you have never seen before, but you would still know that it was an insect because it has similar characteristics to known insects.

However, what if it doesn’t look similar to anything?
You can recognise a new tree species as a tree because all trees are similar in some ways. The crew of the Endeavour encountered many plants and animals, the likes of which had never been seen before. The scientists described the features so the plants could be classified at a later date back in England.

Step 4: Group like with like

After doing basic classification, we start looking at features. What other species have the same or similar features? Species with the same physical features were put into the same groups. These groups, based on physical similarities, were originally defined by Carl Linnaeus.

Linnaeus was the first scientist who developed a standardised classifications system. He described this for the first time in his book Systema Naturae (1735). This book and others were on HMB Endeavour to help Banks and his fellow scientists classify what they saw. 

The basic method for classification remains the same as when HMB Endeavour went on its voyage. We also still use the ‘binomial’ (two-name) naming system that Linnaeus originally defined in Systema Naturae. However, the groups that species are sorted into have changed significantly. This is mainly due to scientific advancements such as genetics.

Many of the species found in Australia had known variants found on other continents. The pictures, notes and samples of various species were taken back to England. These collections were worked on for over a decade after the Endeavour voyage. The Banksia plants, for example, were similar to the Proteas that had recently been found in Africa. The African and Australian plants had a lot of structural similarities. These structures had not been seen in English plants.

Adaptations

We now know that these structural features help the plants survive in the dry, nutrient-poor Australian (and African) environment. 

Examples of these features include:

• Exceptionally hard seeds. The seeds of the Banksias will only germinate after fire, and they are protected from droughts and poor conditions. After a fire the seeds germinate; this adaptation is called serotiny. The ash left behind after a fire is nutrient rich and provides the perfect environment for growing seeds. The seeds also have fewer plants to compete with for resources: water, sunlight, and nutrients.
• Large amounts of nectar. Banksia plants have a large amount of nectar and brightly coloured flowers. These flowers attract a wide range of pollinators and increase the chance of pollination. It is important to attract pollinators in Australia as in many Australian environments pollinators can be rare.
• Leaves covered in tiny hairs. Some Banksia leaves are covered in tiny hairs. These tiny hairs ‘catch’ water around the leaves. Having a layer of ‘caught’ water decreases the amount of water that gets lost through the leaf surface.
• Hard, waxy leaves (Sclerophyllous). A hard outer surface of the leaves protects the leaves from the sun and reduces water loss. It also gives Australian plants their blue/green colour, which is more obvious in Eucalypts.
• Lateral roots/cluster roots (Proteoid). Plants have roots that grow out along the top of the soil. These increase the plant’s ability to obtain water and nutrients.

Activity

Activity – Down to one

Instructions

1. Gather 10–20 objects (or pictures) together in a group. The more objects you have, the longer the activity will take. The more similar the objects are, the harder this activity will be.
2. Tell students they have to divide the objects by asking one yes/no question based on observable characteristics: e.g. Does it have red on it? Does it have legs?, etc. You should now have two groups of objects.
3. Ask students to split one of the groups of objects using a yes/no question based on observable characteristics. Keep repeating this process until you have each object in a ‘group’ by itself.

Notes

• This exercise becomes more challenging if you choose similar objects.
• Students have to base the yes/no questions only on things they can observe; they have to pretend they have no prior knowledge.
• This can be done as a full class exercise and the students can be the ‘objects’ that are classified. Get one student to split the rest of the students into groups based on hair colour and clothing (especially fun and challenging if they are wearing a uniform).

Explanation
It can be very hard for students to isolate differences between objects. Getting students to define differences, especially on very similar objects, forces them to consider how and why they classify animals or objects. Taxonomers all over the world face these challenges and they are often the cause for worldwide scientific debate (e.g. the difference between moths and butterflies or frogs and toads.)