Plant groups - NSW Department of Education

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.
Lesson 18/20 More about classifying plants
1
plants
Are there roots and stems?
no
yes
Are there leaves?
no
algae
yes
bryophytes
Are there seeds?
no
yes
pteridophytes
Are there flowers?
no
gymnosperms
yes
angiosperms
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.
2
Living things
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 _________________
2 _________________
Lives in many
environments; leaves in
many shapes, roots to
absorb water and
minerals, seeds and
flowers for reproduction
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
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Usually lives in water,
either floating or
attached to the bottom;
does not have roots,
stems or leaves
4 _________________
5 _________________
Lives in many
environments; needleshaped leaves, extensive
roots and stems but no
flowers
© 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.
4
Living things
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
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Hormosira is 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.
6
Living things
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.
spore capsule
simple leaves
attachment
© State of New South Wales, Department
of Education and Training, 2004
Mosses on the forest floor
Source:
© Jane West
The attachments on a moss are not roots. They do not absorb water and
minerals in the way that true roots do.
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Liverworts
Below is 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
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Living things
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.
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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:
10
© Jane West
Living things
The following diagram also shows some other features of pteridophytes.
frond (fern leaf)
spores for reproduction
stems joining roots and leaves
roots absorb water and minerals
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.
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Tree fern
© 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.
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Living things
needle-like leaves
cone containing
seeds for reproduction
stems
root system underground
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
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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
•
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?
no
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.
14
Living things
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.
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Plant groups
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 _______________
_______________
•
have leaves but ________ roots
bryophytes
or ________.
pteridophytes
gymnosperms
16
_______________
•
___________ plants
•
live in __________ places
•
reproduce by ___________
•
have leaves
_______________
•
underground _______________
_______________
•
reproduce by _______________
•
roots, stems and leaves
_______________
•
produce seeds in
_______________
_______________
_______________
Living things
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.
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You should 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.
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Living things
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.
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What have 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)
•
have leaves but no roots or stems
moss, liverwort
•
small plants
•
live in moist places
•
reproduce by spores
•
have leaves
•
underground stems
•
reproduce by spores
•
roots, stems and leaves
•
produce seeds in cones
•
have roots, stems and leaves
•
flowers produce seeds which are
protected inside fruit.
bryophytes
pteridophytes
gymnosperms
angiosperm
20
treefern, bracken,
fishbone fern, maidenhair
fern
cycad, fir tree, pine tree,
cypress, spruce, ginkgo,
redwood
wheat, tomato, coconut
palm, grass, gum tree,
peach tree, apple tree,
lettuce, barley, banana
palm, blackberry, plum,
pea, dandelion,
oak (makes acorns),
sycamore, broadbean
Living things
Exercise
Living things
Name
___________________________
Teacher
___________________________
Exercise: Plant groups
plants
Are there roots and stems?
no
yes
Are there seeds?
Are there leaves?
no
algae
no
yes
bryophytes
yes
pteridophytes
Are there flowers?
no
gymnosperms
1
yes
angiosperms
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
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b
pine tree
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)?
___________________________________________________
___________________________________________________
___________________________________________________
___________________________________________________
___________________________________________________
___________________________________________________
22
Living things
b
Why? (What extra information did you need to make
a decision?)
___________________________________________________
___________________________________________________
___________________________________________________
___________________________________________________
___________________________________________________
___________________________________________________
___________________________________________________
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