Lesson 1
Content Section - What is Algae?
Algae are organisms that are like plants
and vegetables. They are commonly
found living in the sea, rivers, lakes or
ponds. All algae make energy from the sun.
There are two different types of algae and
they are called “Macroalgae” and “Microalgae”.
Macroalgae are commonly
known as “seaweed”. The
word “macro“ means big so
you can think of a big plant
that lives in the sea. many cells that let the macroalgae function. The main parts of the macroalgae are
“the holdfast”, “the blade”, “the frond”,
Plants
and Seaweed
“the
stipe”,
“the thallus”, “the mid-rib”
and “the air-bladders”.
The holdfast has an appearance similar to
the roots of plants but it does not provide
Flower
Air Bladder
Leaf
Frond
Stem
Thallus
This is Algeena who will be giving us
information on macroalgae.
Blade
Midrib
This is Mike who will be giving us
information on microalgae.
Holdfast
Roots
Stipe
Microalgae are often called “phytoplankton”. The word “micro” means
very small so you can think of a small
plant that lives in the sea, rivers, ponds or
lakes. They are so small that you will be
unable to see them in the water with your
eyes. They are normally viewed under a
microscope.
Macroalgae (Seaweed) is a multicellular
organism. This means that they contain
Rock
any nutrients to the macroalgae. Nutrients
are absorbed by the entire macroalga from
the water. The holdfast provides support
to the macroalga.
The blade is like the leaf of a tree and the
stipe is like the stem of a flower, if
present.
BioMara gratefully acknowledges the following funders:
A project supported by the
European Union’s INTERREG
IVA Programme managed by the
Special EU Programmes Body.
Lesson One. Page
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The stipe transports nutrients to the holdfast. A collection of blades is known as a
frond. The body of the macroalgae is known
as the thallus.
Some macroalgae have air-bladders to help
them float. The air-bladders contain gas
and help lift the macroalgae to the surface
so that the organisms can get
sunlight. Other macroalgae that
do not have air-bladders have long
stipes to help them float to the surface. Some macroalgae have a midrib which are located in the centre of
the fronds.
Macroalgae are divided by their colour
into brown, green and red macroalgae. The
colour of the macroalgae are due to the
different pigments within the organisms.
There are brown, green and red pigments
within the various macroalgae. All macroalgae have green pigments so they can make
energy from the sun.
Maerl is another type of marine alga. It
has a red colour and forms a tough crust.
Maerl is small in size and you could hold it
in your hand. Unlike other macroalgae they
are not attached by a holdfast but live on
the sea bed with the sand.
Microalgae are small floating organisms
that contain one cell and so are called
“unicellular” organisms. The cell is surrounded by a cell wall. Microalgae can make
their own energy and store their energy in
the cell. Microalgae are different in their
size, shape and colour. They are very small
in size, usually one quarter of a millimetre.
The colour of the microalgae cell depends
on their pigments. They can either appear
blue-green, yellow, brown or orange.
Diatoms are a type of microalgae. They
have different shapes. Some are shaped
like spheres, elliptical (shaped like a rugby
ball), triangles and other diatoms may be
shaped like a stars.
They contain tiny amounts of oil within
their cell. The oil helps them move within
the water to find their food and nutrients.
They are weak swimmers so the water
currents help them to move.
A diatom cell is surrounded by a silica shell
which makes the cell wall. The silica looks
like glass and is used to protect the cells.
The cell wall within the diatom is like a box
with an overlapping lid. They cannot move
themselves so they float free.
The second type of microalgae are called
dinoflagellates. Most dinoflagellates have
two “flagella” which appear like short tails
that help them move through the water.
One flagellum is wrapped around the cell
and the other is visible and helps the
microalgae move. They can also use the oil
within their cell to sink or swim.
Dinoflagellates are surrounded by a tough
shell which they use for protection.
Certain types ofdinoflagellates glow in the
dark at night when disturbed.
Diatoms and dinoflagellates grow very
quickly and large amounts are called algal
bloom.
Algal blooms can cause problems for the
environment. Both of these microalgae have
the ability to cause food poisoning. Shellfish may eat the microalgae as their food
and if humans then eat the shellfish they
may get sick. Some algal blooms are very
beneficial to the environment making huge
amounts of food for fish.
The two main types of microalgae are
“Diatoms” and “Dinoflagellates”.
Lesson One. Page
2
Activity Section – Lesson 1 – What is Algae?
Brief Summary
Aim: The overall aim of this lesson is to introduce algae and distinguish
between the different types of algae.
Algae are divided into macroalgae which are commonly known as seaweed
and microalgae which are sometimes known as phytoplankton. Both
macroalgae and microalgae produce oxygen.
Marcoalgae are large algae and they look like plants. They are multicellular as they contain many cells. They contain a “holdfast” which can be attached to sand, boats or rocks. They contain a “stipe” similar to a stem of
plants. They contain “blades” similar to leaves of a plant and a collection
of blades are called “fronds”. Some macroalgae have “air-bladders” this
helps them float to the surface to catch the sun. Other macroalgae have
no “air-bladders” just long flexible stipes.
Macroalgae are divided into brown, green and red macroalgae. The
different colours are due to the pigments brown, green and red pigments
within the macroalgae.
There is another type of marine alga which is called “Maerl”. These are
very small and are unattached to rocks so they live on the sea bed. They
have a hard calcium crust and are red or brown in colour. Whenever they
die they lose their colour and turn grey.
Microalgae are much smaller organisms. They can only be seen under a
microscope. They are unicellular which means they have only one cell. They
are like floating plants and they are unattached. There are two common
types of microalgae. Diatoms are one variety and they have oil within their
bodies. This helps them to float. Dinoflagelletes are another variety of
microalgae which have “flagella”. The flagella help the dinoflagellates to
swim. Certain varieties of dinoflagellates glow in the dark at night when
disturbed.
Lesson One. Page
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Learning Outcomes:
►► Explain briefly what algae is and to describe the structure of macroalgae and flower.
►► Describe the difference between algae and flower.
►► Describe the two different varieties of algae by providing details about the colours of
macroalgae and the two different varieties of microalgae.
Introduction:
Recall the structure of plants/ flowers. (Use an example of a real plant or flower).
Teacher will explain by the use of an image the difference between macroalgae (seaweed)
and microalgae (phytoplankton).
Pupils will observe that macroalgae and microalgae have different features.
Older pupils may discuss in their own words features of macroalgae (seaweed) and
microalgae.
Activities:
Activity 1- Label the different parts of macroalgae (seaweeds) and a flower.
Activity 2. Select the key words in the box associated with macroalgae, microalgae
and flower.
Activity 3. Show the different varieties of macroalgae and microalgae.
Activity 4. Crossword
Activity 5. Compare the length of different varieties of macroalgae. Draw a graph
of the different lengths.
Final Activity
This will depend on the age of the class and the activity
chosen and focus of the lesson.
Teacher briefly revises the main learning objectives.
►► Teacher will test the knowledge of pupils by getting them draw their own diagram of a flower and macroalgae and label it.
►► Teacher and class discuss the differences between plants and algae. Teacher
will write on the board the answers from the pupils. If required the teacher
will show the class the images of macroalgae and microalgae as a visual aid.
►► Pupils will discuss the different varieties of macroalgae and microalgae and also
the sizes of macroalgae (if Activity- 5 is completed).
Vocabulary: macroalgae, microalgae, holdfast, frond, air-bladder, thallus, stipe, pigments
and flagella.
Lesson One. Page
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Curriculum Links
Scotland
Curriculum for Excellence
Level 1
Literacy and English
Listening and Talking Finding and using information
Reading
Finding and using information
Numeracy and Mathematics
Number, Money, Measure
Measurement
Information Handling
Data Analysis
Sciences
Planet Earth
Biodiversity and
Interdependence
I can identify and discuss the purpose, key words and main ideas
of the text. LIT 1-04a
I can find, select, sort and use information for a specific
purpose. LIT 1-14a
I can estimate how long an object is. MNU 1-11a
I have explored a variety of ways in which data is presented and
can ask and answer questions about the information it contains.
MNU 1-20a
I can sort living things into groups and explain my decisions.
SCN 1-01a
Level 2
Literacy and English
Listening and Talking
Finding and using information
Reading
Finding and using information
Numeracy and Mathematics
Number, Money, Measure
Measurement
I can identify and discuss the purpose, main ideas and
supporting detail contained within the text. LIT 2-04a
I can find, select and sort information from a variety of sources
and use this for different purposes. LIT 2-14a
I can use my knowledge of the sizes of familiar objects or
places to assist me when making an estimate of measure.
MNU 2-11a
Information Handling
Data Analysis
I can interpret and draw conclusions from the information
displayed. MNU 2-20a
Sciences
Planet Earth
Biodiversity and
Interdependence
I can relate physical and behavioural characteristics to their
survival or extinction SCN 2-01a
Skills: Observe, record, present findings, report and classify.
Lesson One. Page
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Ireland
National Council for Curriculum Assessment (NCCA)
First Class, Second Class
English
Oral Language
Reading
Writing
Mathematics
Measures – Length
Data- Representing and
interpreting data
Social Environmental and
Scientific Education
(SESE)
Science
Living things –
Plants and Animals
Geography
Environmental awareness
and care Caring for my locality
Ask questions that will satisfy his/her curiosity and
wonder. Develop comprehension strategies.
Spell correctly a range of familiar, important and regularly
occurring words.
Estimate, measure and record length using metre and
centimetre.
Represent, read and interpret simple tables and interpret
charts.
Recognise and describe the parts of some living things.
Observe similarities and differences among plants and
animals in different local habitats.
Third class, Fourth class, Fifth class
English
Become aware of new words.
Oral LanguageConfidence in using language
Understand the relationship between text and illustration.
ReadingReceptiveness to language
Mathematics
MeasuresLength
Representing and
interpreting data
Measure length using appropriate metric units.
Organise, represent and interpret data.
Social Environmental and
Scientific Education (SESE)
Become familiar with the characteristics of some major
Science- Environmental
groups of living things.
Awareness
Geography
Investigate the influence of various features on plants.
Skills: Record, present findings, sort and group features.thinking, problem solving,
working with others and managing information.
Lesson One. Page
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Northern Ireland
Council for Curriculum Examination and Assessment (CCEA)
Key Stage 1
Language and Literacy
Talking and listening
Participate in talking and listening in learning.
Reading
Read, explore, understand and make use of traditional text
explore and interpret a range of visual text.
Writing
Use a variety of skills to spell words.
Mathematics and
Numeracy
Measures
Understand and use the language associated with length.
Handling Data
The World Around Us
Interdependence
Place
Discuss and interpret the data extract information from
charts.
How plants rely on each other within the natural world.
Identify ways in which living things depend on and adapt to
their environment.
Key Stage 2
Language and Literacy
Talking and listening
Reading
Writing
Mathematics and
Numeracy
Measures
Handling Data
The World Around Us
Interdependence
Place
Identify and ask appropriate questions to seek
information.
Represent their understanding of text in a range
ways including visual and oral.
Use a variety of skills to spell words correctly.
Understand the relationship between units and convert one
metric unit to another.
Classify, record and present data
explain their work orally and draw conclusions.
How living things rely on each other within the natural
world.
Identify ways in which plants and animals depend on
features and materials in places.
Skills: Thinking, problem solving, working with others and managing information.
Lesson One. Page
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Activity 1.
Name
Label the different parts of macroalgae
(seaweeds) and a flower.
THALLUS
FLOWER
Ask the pupils to label the appropriate parts
of the macroalgae and flower by using the key
words in the table.
FROND
STEM
BLADE
ROOTS
AIR
BLADDER
LEAF
STIPE
HOLDFAST
Lesson One. Page
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Activity 2.
Name
Select the key words in the box associated with macroalgae, microalgae and flower.
MacroalgaeMicroalgae
Flowers
1._________________1.______________1._____________
2._________________2._______________2______________
3.__________________
3.________________
3._____________
4.__________________
4.________________
4._____________
Microscope
Stem
Flower
Holdfast
Phytoplankton Seaweed Multicellular Blade
Roots
Leaf
Diatoms
Flagella
Describe by writing one sentence the differences between macroalgae and microalgae.
Macroalgae
Microalgae
Lesson One. Page
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Activity 3.
Show the different varieties of macroalgae and microalgae.
Draw two headings on the board or a large page.
Label the first heading as “macroalgae” and label the other heading as “microalgae”.
The teacher will cut out the images on page 11 and provide the pupils with various
photographs of either macroalgae or microalgae labelled a-l.
Stick blu tak or sellotape to the back of each photograph.
Ask the pupils to locate them underneath the correct heading.
Ask the pupils why they located certain images under the macroalgae/ microalgae section.
Ask the pupils to name the three different colours of macroalgae.
Ask the pupils to name the two different types of microalgae.
Lesson One. Page
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a
b
c
d
e
f
i
h
Lesson One. Page
11
g
j
k
Lesson One. Page
11
l
Activity 4-Crossword
Name
1.
2.
O
M
10.
E
13.
H
8.
C
G
16.
15.
A
R
9.
E
11.
14.
6.
B
4.
12.
7.
O
3.
E
F
A
E
N
T
18.
19.
5.
17.
P
E
20.
P
1. What is the name of the small red macroalgae
that develop a hard crust?
(5 letters)
2. What is the name of the part of the
macroagae that attaches itself to a rock or
boat? (8 letters)
3. What is the name used to describe the body
of the macroalgae? (7 letters)
4. What helps dinoflagellates swim and moves towards
their food? (8 letters)
5. Name a type of microalgae? (6 letters)
6. Where do both macroalgae and microalgae live?
(3 letters)
7. Give the scientific word for seaweed? (10 letters)
8. What is the name of the structure on some mac
roalgae that help them float? (10 lettters)
9. Name the environmental condition which arises
when there is an excessive growth of
dinoflagellates? (11 letters)
10.What is the structure on a flower similar that
resembles the blade on macroalgae? (4 letters)
O
S
11. What is the name of the substances that gives
both plants and algae their colour? (7 letters)
12. What is the name of the instrument that you look
through to view microalgae? (10 letters)
13. What is the name of the structure of the
macroalgae that resembles the leaf?
(5 letters)
14. How many cells do each microalgae have?
(3 letters)
15. What do microalgae have inside their bodies to
help them float? ( 3 letters)
16. What is the name of the structure of a flower
that is similar to the stipe of a macroalgae?
(4 letters)
17. What is another name often used to describe
the body of the macroalgae? (5 letters)
18. What is the name of the part of the macroalgae
that consists of many blades? (5 letters)
19. What is the common name of macroalgae?
(7 letters)
20. Name another place that algae is also found?
(5 letters)
Lesson One. Page
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Activity 5: Name
Compare the length of different varieties of macroalgae.
Draw a graph of the different lengths.
To measure the length of various macroalgae.
Materials: ruler in centimetres and millimetres
Method:
The length of the macroalgae are given in the table below.
1 metre = 100 centimetres.
Graph the different lengths of the macroalgae on graph paper.
Draw a bar chart to show the different lengths of the macroalgae.
This will show the tallest and the smallest of the macroalgae.
(Labelled diagram of bar chart y-axis length, x-axis name of macroalgae)
Teacher can show the real images of each species to the pupils.
(The length shown in the table below is an estimated length)
Recording Sheet for the lengths of Macroalgae
Macroalgae
Laminaria digitata/ Oarweed
Saccharina latissima/ Seabelt
Length
1 metre (m)
4 metres (m)
Ascophyllum nodosum/ Knotted Wrack 1 metre (m)
Fucus vesiculosus/ Bladderwrack
1 metre (m)
Chondrus crispus/ Irish Moss
20 centimetres (cm)
Palmaria palmata/ Dulse
40 centimetres (cm)
Ulva lactuca/ Sea lettuce
18 centimetres (cm)
Lesson One. Page
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Answer sheet -Lesson 1 – What is Algae?
Activity 1 - Label the different parts of macroalgae (seaweeds) and a flower.
Flower
Air Bladder
Leaf
Frond
Stem
Thallus
Blade
Holdfast
Roots
Stipe
Lesson One. Page
15
Activity 2 –
Select the key words in the box associated with macroalgae, microalgae and flower.
Macroalgae- Holdfast, Seaweed, Blade, Multicellular
Microalgae- Microscope, Phytoplankton, Flagella, Diatom
Flower – Stem, Flower, Leaf, Roots
List the differences between macroalgae, microalgae and a flower.
Answer:
Macroalgae (seaweed) have blades, holdfast, stipe, air bladders, fronds, thallus. They
have no root system and they do not get their nutrients from the soil.
Microalgae have just one cell and they are able to float in the water. Some microalgae
have flagella to help them swim towards their food. They absorb their nutrients through
their cell wall.
Flowers have stems, leaves, roots, root system that provides them with nutrients from
the soil.
Flowers, macroalgae and microalgae all provide oxygen for the environment.
Lesson One. Page
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Activity 3 - Show the different varieties of macroalgae and microalgae.
a
Dinoflagellate- microalgaeKarenia mikimotoi
d
b
c
macroalgae - Ulva intestinalis
macroalgae- Palmaria palmata
e
f
Diatom - microalgae Chaeroceros
macroalgae - Fucus vesiculosus
g
i
h
macroalgaeSaccharina latissima
j
Dinoflagellate - microalgae
Ceratium cf lineatum
k
Diatom - microalgae Asterionellopsis
macroalgae- Maerl
macroalgae - Chondrus crispus
l
macroalgae Ascophyllum nodosum
macroalgae -Ulva lactuca
The colours of macroalgae are red, green and brown
The two different varieties of microalgae are diatoms and dinoflagellates.
Diatom cells can be joined together or can have spines to provide protection. They come
in a variety of shapes spheres, triangle, elliptical, or like star. They are very pretty and
have a silica wall which appears like glass.
Dinoflagellates can swim with the help of the flagella. Look carefully for the flagella. It
appears like a small tail. They appear as individual cells swimming alone.
Lesson One. Page
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Activity 4 - Crossword
1.
5.
M
D I
H O L D F A S T
E
E
H
10.
2.
13.
B
L
3.
A
R
F
L
11.
8.
A I
4.
A T O M
R B L
L
12.
D
E
14.
G
M
N
E
15.
I
L
S T E M
N
S T I
17.
P E
M
S E A
9.
A
L
G
A
L
16.
18.
6.
C
A D D E R
F L A G E L L
U
P
M I C R O S C O P E
A
7.
O
A
L
G
A
E
B
L
F R O N D
O
S E A W E E D
19.
20.
M
P O N D S
Lesson One. Page
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Plants and Seaweed
(image 1)
Flower
Air Bladder
Leaf
Frond
Stem
Thallus
Blade
Midrib
Holdfast
Roots
Stipe
Rock
Microalgae
· are very small in size and can usually be seen using
a microscope
· are found floating and swimming in the water
· have oil inside their cell to help them float, some microalgae
have flagella to help them swim
· are unicellular organisms as they only have one cell
· live in both freshwater ponds and lakes and also in the sea
The Algae Family
Macroalgae
· are big in size and can found on rocks, sand or in the water
· are attached to rocks or sand using their holdfast
· contain stipe, air-bladders and fronds to
help them float
· are multicellular organisms as they have
many cells
· live in freshwater or the sea and they can be
found washed up on the rocks or the shore
(image 2)
Microalgae - Diatom
(image 3)
Cell Wall
Spines for protection
Oil within the cell
Microalgae - Dinoflagellate
Cell Wall
Oil within the cell
Flagellum