Life's Hidden Order
Divided up
How to organise life
Carl Linnaeus was a brilliant botanist. He and his students explored many countries and discovered thousands of new types of plants. However, he is most famous for finding a way of organising these discoveries and naming them; a system that every biologist still uses today.
Complicated flowers
Download a pdf of the instructions here.
You will need...
A flower (preferably still growing) - anything from a garden
weed to tree blossom will do!
A pencil
Paper
How long will it take?
You may like to spread this over two lessons. In the first lesson you can get the students to draw and categorise their plants, in the second you can have a class discussion. Alternatively the students can draw their plants at home and you will need only one lesson for the discussion.
What to do...
Students can work on their own or in small groups if they are more likely to contribute this way. They can provide their own plants or you can supply each group with one - if you use plants from the table below you can see which ones are most closely related to each other, choose two or three from each group.
1. Draw a picture of your flower. In Linnaeus' time there was no photography and part of a botanist's job was to draw very accurate pictures of the plants they were studying. Don't forget to include the leaves; you may even want to carefully look at the shape and type of roots.
You may want to guide the students by posing some questions like...
How tall is the flower?
What colour it is?
Does it have a smell?
What shape are the leaves?
How many petals are on each flower?
Not all the questions you ask need to be helpful in the classification. Classification is made ever easier if you have yes or no answers.
2. Write out the key features of your plant. Look at the overall shape and height before looking at it in more detail.
3. As a class have a look at the different features you have picked out as being important. First make a list of all the key characteristics or questions they asked themselves. Make a note of how many times the same question came up. For example, every group might ask 'What colour is the flower?' but only a few may ask 'How many stamen does the flower have?'.
4. Ask the class to decide which the most important questions are. Is the shape of the leaves more important than the colour of the flower? Choose a few of the most important questions to help you classify the class's plants.
5. Using these questions try to group together the plants with similar characteristics. It doesn't really matter if they have grouped all the white flowers together or all the plants of the same height, as long as they are putting them in some kind of order!
6. They may want to do this by someone saying, 'My plant's flower have 6 petals and the leaves are drak green and shiny', and see if anyone else matches those characteristics. The class can mingle, joining together into groups with people with similar plants.
7. Were they right? You can use the chart below to help you decide which plants are most closely related.
The following plant classification chart for some common types of
flowering plant in the UK has many omissions. Yet it
illustrates some of the ways plants can be classified into the
larger groups (the columns do not follow class, order or
family).
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Plants |
Don't produce seeds |
(mosses, algae, ferns) |
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Plants that produce seeds |
plants that don't flower |
(conifers) |
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Plants that flower |
Leaves with branched veins Flowers with 4 or 5 petals (or multiples of 4 or 5) |
There are usually a large number of stamens. Can clearly tell which are petals and which are sepals (rosids) |
Raspberries, strawberries, apples, apricots, roses |
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Plants produce long pods containing seeds (rosids / fabaceae) |
Peas and beans |
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Each flower head is often made up lots of much smaller flowers (asterids / asterales) |
Sunflowers, daisies, dandelions |
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Leaves with parallel veins and 3 or 6 petalled flowers (or multiples of 3) (monocots) |
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Orchids, lilies, daffodils, tulip, grass, bamboo, pineapple, reeds and rushes |
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Branched veins on leaves but flowers with a multiple of three petals. (magnoliids) |
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Magnolia, laurel |
Many plants are now categorised genetically, not necessarily by how they look. But the key characteristics to look for are the number of petals, how the petals are arranged in the flower, and the leaves.
A series of questions like these would be best for categorising these plants...
What is the vein structure on the
leaf?
How many petals does the flower have?
How many stamens does the flower have?
Is the 'flower' a collection of many flowers?
What kind of seeds does the plant have?
Curriculum Links
Science
QCA Unit:
7A Variation and
Classification
Key Concepts
1.1 Scientific thinking
b) Critically analysing and evaluating evidence from
observations and experiments.
Key Processes
2.2 Critical understanding of evidence
a) obtain, record and analyse data from a wide range of
primary and secondary sources, including ICT sources, and use their
findings to provide evidence for scientific explanations
Curriculum Opportunities
c) use real-life examples as a basis for finding out about
science
h) explore contemporary and historical scientific developments and
how they have been communicated
APP Links
AF2 Understanding the applications and implications
of science
Scottish Curriculum Links
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Science
|
SCN 2-01a |
Planet Earth - Biodiversity and interdependence I can identify and classify examples of living things, past and present, to help me appreciate their diversity. I can relate physical and behavioural characteristics to their survival or extinction. [Note: level 2] |
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SCN 3-01a |
Planet Earth - Biodiversity and interdependence I can sample and identify living things from different habitats to compare their biodiversity and can suggest reasons for their distribution. |
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SCN 4-01a |
Planet Earth - Biodiversity and interdependence I understand how animal and plant species depend on each other and how living things are adapted for survival. I can predict the impact of population growth and natural hazards on biodiversity. |
Divided up
If you enter the school office you may find
lots of paper information on each student. This is very
likely to be ordered, perhaps by year group and then
alphabetically. Organising information like this makes it
easier to find what we are looking for and also understand how it
fits together.
Carl Linnaeus looked at nature in a similar way and spent his life putting it in order, at least on paper.
The image shows Linnaea borealis, a plant that was named after him.
To begin with he divided everything living into plants or animals; pretty obvious so far. He then divided animals further into groups like mammals, reptiles or birds, and he divided plants into smaller groups as well. He continued dividing the groups again and again, the members of each smaller group having something in common, until there was only one type of living thing in a group; this was a single species.
Working out how to group similar plants or animals together is not simple. First Linnaeus had to decide what the most important characteristics were. For animals, this could mean having feathers or scales. In plants, he was famous for dividing them by the number of stamen or stigma the flowers had.
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Key fact: Dividing plants and animals up into groups makes it easier to understand which species are most closely related - it also allows biologists to look at differences between animals of the same species. |
Download a pdf of the instructions here.
You will need...
A flower (preferably still growing) - anything from a garden
weed to tree blossom will do!
A pencil
Paper
What to do...
You will find out just how hard it is to pick the important features for classifying plants.
1. Draw a picture of your flower. In Linnaeus' time there was no photography and part of a botanist's job was to draw very accurate pictures of the plants they were studying. Don't forget to include the leaves; you may even want to carefully look at the shape and type of roots.
2. Write out the key features of your plant. Look at the overall shape and height before looking at it in more detail. You can do this by asking yourself a question and then answering it... 'What shape are the leaves?' - 'They have five small leaves attached to a single point'. Take a look at this picture of a flower to help you decide which the important parts to look at are.
Here are a few questions you may want to ask...
How tall is the flower?
What colour it is?
Does it have a smell?
What shape are the leaves?
Are their veins visible on the leaves and what shape are
they?
How many petals are on each flower?
3. As a class, have a look at the different features you have picked out as being important.