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- 1. Lesson 18/20 Moreabout classifying plants 1 Plant groups In this lesson on plant groups, you will be investigating a system of classifying plants that is used today. What are the main plant groups? There are five groups of plants in the modern classification system. They are: • algae • bryophytes • pteridophytes • gymnosperms • angiosperms. What features are used in plant classification? What features are used to classify plants? The key below shows you some of the main groups of plants.
- 2. 2 Living things Arethere roots and stems? Are there seeds? Are there flowers? bryophytes angiosperms plants no yes no yes no yes pteridophytes gymnosperms Are there leaves? algae no yes Plant group key Activity: What features are used in plant classification? Make a list of the features used to classify plants. __________________________________________________________ __________________________________________________________ __________________________________________________________ Plants are classified using structural features including roots, stems, leaves, seeds and flowers. A quick look at each plant group The table on the next page contains a drawing and description of an example from each plant group.
- 3. Lesson 18/20 Moreabout classifying plants 3 Activity: A quick look at each plant group Use the key above to identify the group that matches each example. Drawing Description Plant group Lives in damp places, often in water; simple leaves but no roots, stems or flowers 1 _________________ Lives in many environments; leaves in many shapes, roots to absorb water and minerals, seeds and flowers for reproduction 2 _________________ Usually lives in damp, shaded places; roots, stems and leaves in fronds but no flowers or seeds 3 _________________ © State of New South Wales, Department of Education and Training, 2004
- 4. 4 Living things Usuallylives in water, either floating or attached to the bottom; does not have roots, stems or leaves 4 _________________ Lives in many environments; needle- shaped leaves, extensive roots and stems but no flowers 5 _________________ © State of New South Wales, Department of Education and Training, 2004 Check your response by going to the suggested answers section. You have classified the major groups of plants now take a more detailed look at the plant groups. A more detailed look at plant group features In this section, you will read about each of the main plant groups. Then, there is a summary for you to complete at the end of this section. Algae Have you ever been to the seaside? All around the rock pools and even in the water there are plants. These plants are called seaweeds. There are a large number of different seaweeds. Seaweeds are plants that belong in the group, algae.
- 5. Lesson 18/20 Moreabout classifying plants 5 Algae © State of New South Wales, Department of Education and Training, 2004 Algae can be green, red or brown. Ulva is an example of a green algae. It is sometimes called sea lettuce. Corallina is an example of a red seaweed. Look at the photograph and diagram of another type of algae in the following pictures. Hormosira sp © State of New South Wales, Department of Education and Training, 2004
- 6. 6 Living things Hormosirais an example of brown algae. This plant is sometimes called Neptune’s necklace. It lives in rock pools on the seashore. Here is a drawing of Hormosira. It gives a more detailed view of this plant. Diagram of Hormosira © State of New South Wales, Department of Education and Training, 2004 So far, you know that algae live in seawater. There are other types of algae that live in freshwater ponds, rivers or just very wet places. What makes algae different from other plants? Algae are different because of what they do not have, rather than what they do have. Algae do not have roots, stems or leaves. Activity: Algae Think back. Why are algae classified as plants? __________________________________________________________ __________________________________________________________ Algae can make their own food. All the organisms that make their own food are called plants. However, algae are very simple. And there are animals that are very similar to algae, except that they cannot make food. In the most recent classification systems, algae and these animals that are similar to algae are put into a kingdom of their own called the protists. Protistos is a Greek word that means the very first. So protist is the kingdom for the simplest organisms, including algae.
- 7. Lesson 18/20 Moreabout classifying plants 7 Bryophytes Have you ever been in a damp dark forest? Did you notice the green flat plants covering the forest floor? Have you noticed a bright green plant that looks and feels like velvet growing in a dark and damp corner of your garden? If you have, then you‘ve seen some examples of the group of plants called bryophytes. Mosses and liverworts are bryophytes. Bryo- means moss in Greek and -phyte means plant, so bryophytes are plants that are like mosses. So far you have learned that bryophytes are small plants that grow in damp places on land. But what are the other features of mosses and liverworts? Mosses The 'carpet' in the background of the photograph ‘Mosses on the forest floor’ below is a moss. Compare the photograph with the diagram ‘Moss plant’. This will give you a better idea of some features of mosses. Mosses on the forest floor Source: © Jane West spore capsule simple leaves attachment © State of New South Wales, Department of Education and Training, 2004 The attachments on a moss are not roots. They do not absorb water and minerals in the way that true roots do.
- 8. 8 Living things Liverworts Belowis a photograph of some liverworts growing with some moss. Source: © Barbara Gurney Liverworts are often found on the forest floor. Compare the photograph and diagram of the Liverworts to get a better idea of some features of liverworts. spore capsule simple flat leaves Diagram of a liverwort © State of New South Wales, Department of Education and Training, 2004
- 9. Lesson 18/20 Moreabout classifying plants 9 Did you notice tiny structures sticking out of the mosses and liverworts in the photographs and drawings? These structures are spore capsules. They contain tiny spores for reproduction. Activity: Liverworts Now answer these questions. 1 Do liverworts have roots? _________________________________ 2 Do liverworts have flowers? _______________________________ 3 Why are liverworts called bryophytes? _______________________________________________________ _______________________________________________________ Check your response by going to the suggested answers section. Pteridophytes (ferns) Do you have any indoor plants? Many plants sold as house plants are ferns. Common ferns include tree ferns, maidenhair ferns, fishbone ferns and bracken. Pteridophyte comes from two Greek words. Pteris means a fern and - phyte means a plant. Activity: Pteridophytes (ferns) What is a pteridophyte? ___________________________________________________________ ___________________________________________________________ A pteridophyte is a plant that is like a fern. The leaves of pteridophytes often have a lacy appearance. This can be seen in plants like the maidenhair fern. Fern leaves are called fronds.
- 10. 10 Living things Fern ©State of New South Wales, Department of Education and Training, 2004 And have you ever noticed the back of fern fronds? If you look closely, you may see some little brown spots. These are spores. Ferns reproduce by spores. Look at the following photograph and find the spores. Then look back at the photograph above. Can you identify spores in the photograph? Spores on the back of a fern leaf Source: © Jane West
- 11. Lesson 18/20 Moreabout classifying plants 11 The following diagram also shows some other features of pteridophytes. spores for reproduction roots absorb water and minerals stems joining roots and leaves frond (fern leaf) A fishbone fern © State of New South Wales, Department of Education and Training, 2004 Pteridophytes, or ferns, are found in many different locations or environments. They need to be in places where there is a fair amount of moisture so you will not find them in a desert! They have roots to absorb water but they need moisture so that spores can move around for reproduction. Pteridophytes, or ferns, can be a pest in some areas. Ferns such as bracken are sometimes called weeds. If you’ve ever had to dig out ferns where they are a problem, then you will have noticed that the stems are underground. One exception to this is the tree fern that is a very tall fern.
- 12. 12 Living things Treefern © State of New South Wales, Department of Education and Training, 2004 Gymnosperms Have you ever noticed the features of a traditional real Christmas tree? If you have, then you already know a lot about the group of plants called gymnosperms. Gymnosperms include cycads, fir trees, pine trees, cypress, spruce, ginkgo and redwoods. In Greek, gymnosperm means “a plant with naked seeds". This is because the seeds of a gymnosperm are not inside a fruit. Instead, a gymnosperm has its seeds inside cones. When the cones open, the seeds fall out. You can see some of the main features of a gymnosperm in the following drawing. It is a drawing of the most familiar gymnosperm – a pine tree.
- 13. Lesson 18/20 Moreabout classifying plants 13 needle-like leaves cone containing seeds for reproduction root system underground stems A pine tree A pine cone © State of New South Wales, Department of Education and Training, 2004 Did you notice the leaves? They are like needles. As well, the other most obvious feature is the cones. Can you identify the leaves and cones in the photograph below? A pine branch © State of New South Wales, Department of Education and Training, 2004
- 14. 14 Living things Angiosperms(flowering plants) The last plant group we'll look at is the one that you are probably most familiar with – angiosperms, or flowering plants. What is the most obvious feature of a flowering plant? The flowers, of course! But, there are some flowering plants that don’t have obvious flowers. See if you can pick the angiosperms (flowering plants). yes no • Is wheat a flowering plant? • Is a tomato a flowering plant? • Is a coconut palm a flowering plant? • Is grass a flowering plant? • Is a gum tree a flowering plant? • Is a peach tree a flowering plant? • Is an apple tree a flowering plant? • Is a lettuce plant a flowering plant? • Is barley a flowering plant? • Is a banana palm a flowering plant? They are all angiosperms, or flowering plants! It may have been harder than you thought to identify flowering plants. It would have been easier for you if you knew that flowering plants produce fruits and seeds. So if the flowers weren’t obvious, then the fruits or the seeds may have been. The drawings below show you some of the different types of fruit produced by flowering plants.
- 15. Lesson 18/20 Moreabout classifying plants 15 blackberry plum pea acorn Fruits of some angiosperms © State of New South Wales, Department of Education and Training, 2004 The following drawings show you some of the different types of seeds produced by flowering plants. dandelion sycamore broad bean Seeds of some angiosperms © State of New South Wales, Department of Education and Training, 2004 Angiosperms can look very different from each other because there are many shapes and arrangements of leaves and stems. Even the roots on angiosperms can have different forms and patterns. But angiosperms have one main similarity. In Greek, angio- means container and sperm means seed. Use this information to carry out the activity below. Activity: Angiosperms What do you think angiosperm means? ___________________________________________________________ ___________________________________________________________ An angiosperm is a plant with its seeds inside a container, or fruit.
- 16. 16 Living things Plantgroups You have read a lot of information about the different plant groups. Now it’s time to summarise what you have learned so far. Activity: What have you learned about plant groups? Complete the following using information from this lesson. Plant group Features Examples algae • no roots, stems and leaves Hormosira • live in _______________ _______________ bryophytes • have leaves but ________ roots or ________. _______________ • ___________ plants • live in __________ places • reproduce by ___________ pteridophytes • have leaves _______________ • underground _______________ _______________ • reproduce by _______________ gymnosperms • roots, stems and leaves _______________ • produce seeds in _______________ _______________ _______________
- 17. Lesson 18/20 Moreabout classifying plants 17 angiosperm • have ______________ _______________ _______________ and _______________ _______________ _______________ • Flowers produce _______________ ______________ that are protected inside _____________ Check your response by going to the suggested answers section. You can now use this information to carry out the exercise below. Go to the exercises section and complete Exercise: – Plant groups. What's next? Have you enjoyed learning about plants and using keys? Would you like to try to draw your own key? Remember, a key uses the structural features of living things to enable you to classify them into smaller and smaller groups. Here's an activity you can try. You might even like to do it as your student research project. Activity: A plant search Go on an excursion to a garden or native bush area. Observe at least five different plants than construct a key that could be used to identify them.
- 18. 18 Living things Youshould show your key to someone else to try in your garden or bush area. How successful were they? Do you need to change your key? Write a few sentences to describe how the key was used. You might like to include drawings or pressed, dried plant cuttings with your key and report for your teacher. If you are overseas, then do not send plants to Australia. They may have diseases that plants in Australia do not have. What did you achieve? Tick what you can do. use a key to classify plants into the main plant groups compare photographs with drawings of plants complete a table summarising the features of the five main plant groups.
- 19. Lesson 18/20 Moreabout classifying plants 19 Suggested answers Check your responses against these suggested answers. A quick look at each plant group 1 bryophyte 2 angiosperm 3 pteridophyte 4 algae 5 gymnosperm Note: alga is one plant; algae is more than one plant of that kind. Liverworts 1 No, liverworts don’t have roots 2 No, liverworts don’t have flowers. 3 Liverworts are called bryophytes because they are similar to mosses. They do not have stems or roots but they do have simple leaves.
- 20. 20 Living things Whathave you learned about plant groups? Plant group Features Examples algae • no roots, stems and leaves • live in water Hormosira (Neptune’s necklace), corallina, ulva (sea lettuce) bryophytes • have leaves but no roots or stems • small plants • live in moist places • reproduce by spores moss, liverwort pteridophytes • have leaves • underground stems • reproduce by spores treefern, bracken, fishbone fern, maidenhair fern gymnosperms • roots, stems and leaves • produce seeds in cones cycad, fir tree, pine tree, cypress, spruce, ginkgo, redwood angiosperm • have roots, stems and leaves • flowers produce seeds which are protected inside fruit. wheat, tomato, coconut palm, grass, gum tree, peach tree, apple tree, lettuce, barley, banana palm, blackberry, plum, pea, dandelion, oak (makes acorns), sycamore, broadbean
- 21. Lesson 18/20 Moreabout classifying plants 21 Exercise Living things Name ___________________________ Teacher ___________________________ Exercise: Plant groups Are there roots and stems? Are there seeds? Are there flowers? bryophytes angiosperms plants no yes no yes no yes pteridophytes gymnosperms Are there leaves? algae no yes 1 Use the key to identify the group to which each of the plants below belongs. Write the group on the line beside the photograph. a callistemon (bottlebrush) © State of New South Wales, Department of Education and Training, 2004
- 22. 22 Living things b pinetree c fern © State of New South Wales, Department of Education and Training, 2004. 2 Did you find it difficult to classify any of the plants in Question 1? a Which one(s)? ___________________________________________________ ___________________________________________________ ___________________________________________________ ___________________________________________________ ___________________________________________________ ___________________________________________________
- 23. Lesson 18/20 Moreabout classifying plants 23 b Why? (What extra information did you need to make a decision?) ___________________________________________________ ___________________________________________________ ___________________________________________________ ___________________________________________________ ___________________________________________________ ___________________________________________________ ___________________________________________________