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CHAPTER FIVE
Classifying Living
Things
In chapter four, you learnt about the structure and organization of cells. Unicellular
organisms have only a single cell. Most organisms are multicellular because they
have many cells.
Activity 5.1: Talking about two animals
Figure 5.1 Amoeba and oxpecker are both animals.
1.
Work in groups. Talk in Kiswahili. Speak out loud the names Amoeba (you
say it as: Am-i-ba) and oxpecker.
2.
One of these animals is unicellular. Say which it is. Explain in English what
‘unicellular’ means.
3.
Amoeba and oxpeckers are both animals. Name in English the
characteristics that all animal cells have in common.
4.
Amoeba can make you very sick. Explain in English why it is not a good idea
to drink dirty water.
5.
Find out how the oxpecker feeds. Tell your teacher in English.
1
Unit One: What is classification
Glossary
classify – ainisha
identify – bainisha
characteristic – sifa
sort - tenganisha
in common – yenye sifa
sawa
In this chapter we will learn to classify living
things into groups. This helps us to think about
the characteristics that similar organisms
share. It also helps us to identify and name
organisms.
People are very good at sorting things into groups. When grouping different things
together, we use characteristics that all of the things have in common. In the next
activity, you will sort things into groups, by choosing the characteristics that they
share.
Activity 5.2: Sorting things into groups
1.
2.
Collect and bring to the class at
least five bottle tops of different
colours, sizes and shapes.
In groups of five, arrange the tops
into groups using characteristics that
they share in common.
3.
Describe in English the characteristics
that they share in common.
4.
Look at the tops in figure 5.2
and group the tops in the picture
using the four characteristics shown
5.
Copy the table below into your books.
Make sure you have a row for each of
the bottle tops. Fill in the table for each
of the bottle tops shown in Figure 5.2.
bottle top
1
2
colour
blue
Figure 5.2 Sort these bottle
tops into groups into groups
by filling in the table below.
characteristic
shape
size
round
small
3
2
6.
7.
Work in groups. Talk in Kiswahili. How many bottle tops are blue?
Write your answer in English.
Which bottle top is black, round and large? Write your answer in English.
In this activity you have sorted the bottle tops into groups using different
characteristics that they have in common. This is called classification.
Activity 5.3: Sorting organisms into groups
Figure 5.3 Look at these animals and plants. What characteristics do they share?
Work in groups. Talk in Kiswahili. Look at the animals and plants in Figure 5.3.
What characteristics do they have in common?
i. Group the organisms using characteristics that they have in common.
ii. Write down in English the characteristics you used to group them together.
iii. Use the following words to describe the characteristics you use for grouping
the animals and plants: wild, domestic, number of legs, body cover, wings.
8.
Work in groups. Talk in Kiswahili about why classification is important in
everyday life and to scientists. Why is important that a ‘lion’ has the same
name everywhere in the world?
3
Unit Two: Ways to classify organisms
Glossary
1.
poisonous – yenye sumu
system -mfumo
2.
Work in groups. Talk in Kiswahili.
Make list of plants that are good to eat
and a list of those plants that are
poisonous.
Why is it important that everyone
should be able to recognise poisonous
plants?
You have sorted plants into two groups using a single characteristic (poisonous or not
poisonous). This is called an artificial classification system because it uses only one (or a
few) characteristics to group organisms together.
Figure 5.4: Which characteristic is used to group these animals
together?
Activity 5.4: What do these animals have in common?
1. Look at the animals in Figure 5.4. Work in groups. Talk in Kiswahili.
2. Name the characteristic that is used to group these animals together.
3. Talk to one another and agree if these organisms belong to the same group and
why? Are there other ways of grouping these organisms?
All of these animals have wings, but grasshoppers and birds are very different animals.
So are bats and butterflies. Artificial classifications like this are useful for only one thing
4
(such as identifying animals with wings, or recognizing poisonous plants).
The most useful way of classifying organisms is to use a large number of characteristics
at the same time. These are called natural systems of classification. The best ones can
tell us how living organisms are related to each other. We can know a lot about the
characteristics that an organism has when we know what groups it belongs to.
Activity 5.5: What do you have in common with monkeys?
Humans are classified with
chimpanzees and other monkeys in a
group called the primates.
1. Work in groups. Talk in Kiswahili.
What characteristics do you share
with chimpanzees and other
monkeys? What differences are there
between you and monkeys?
Figure 5.5 These animals are
primates.
The animals on the next page are all in a group called mammals. Mammals share lots of
characteristics in common:

They have hair on their bodies

They feed their babies with milk

Most mammals give birth to live young (although a few lay eggs).
Activity 5.5: What is a mammal?
1. Look at the mammals in Figure 5.6 on the next page. The mammals shown all
help humans to live. Work in groups. Talk about the animals in Kiswahili. Do you
agree that these animals all share the characteristics described above?
5
Figure 5.6: These animals are mammals that are useful to people.
2.
Glossary
cow – ng’ombe
dog - mbwa
cat - paka
goat- mbuzi
rabbit - sungura
sheep - kondoo
dog
cow
The
goat
cat
Write one sentence in English
about each of these mammals,
explaining how they are useful
to people. Use the sentences
below to help you.
is useful
for
meat
guarding
homes
milk
skins
Activity 5.7: Comparing the different ways of classifying organisms.
1.
Look again at the parts of this chapter that are about natural and artificial
systems of classification. Work in groups. Talk in Kiswahili.
2.
Write in English one advantage and one disadvantage of natural and artificial
systems of classification.
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Unit Three: Major Groups of Organisms
Figure 5.7: All of these Russian dolls fit inside the largest doll.
These toys are called Russian dolls. The smaller dolls can be put inside the larger
dolls, and all of the dolls can be put inside the largest doll.
The natural classification of living organisms is like these dolls. A kingdom is like
the largest doll in this toy because it contains the largest number of different types of
organisms.
Activity 5.6: What kingdom do you belong to?
Animals, plants and bacteria are all examples of kingdoms.
1.
Work in groups. Talk in Kiswahili. Which one of these kingdoms to you
belong to? How do you know?
7
Unicellular organisms are also very small. They can
only be seen with a microscope. For example,
Bacteria
arecauses
very small.
They
only be seen
with a
Plasmodium
malaria
andcan
Entamoeba
causes
microscope.
Some
bacteria
cause
disease.
amoebic dysentery, Scientists group these organisms in
Mycobacterium
a disease known as
a kingdom calledcauses
Protoctista.
tuberculosis (TB) and Salmonella causes typhoid fever.
Monera is the name that scientists give to the kingdom
of the bacteria.
Figure 5.9 This unicellular
organism causes malaria
There are five
Figure 5.8 Bacteria
kingdoms. Here is a list
of kingdoms:
Fungi are often large enough to be seen without a
microscope. They can make food rot and go ‘bad’.
Yeast and mushrooms are fungi. Yeast is used to
make beer.
Figure 5.10 There are fungi
growing on these fruit
Plants can make their own food. This makes them
very important organisms, because they are food for
many animals, bacteria and fungi. Plants also make
oxygen, which is in the air that we breathe.
Figure 5.11 The banana
tree is a plant
8
Animals have to feed on plants or on animals that
have fed on plants. This group includes all
animals such as insects, spiders, snakes, fishes,
frogs, toads, birds, rats, dogs, lions, goats,
monkeys, human beings, snails and worms.
Figure 5.12 A locust is an
animal
Activity 5.7: One or more than one?
Words that describe one thing are called singular words. An ‘apple’ is a singular
word, it means one apple. Words that describe more than one thing are called plural
words. ‘Apples’ is a plural word. It means more than one apple. Sometimes singular
and plural words are spelt differently.
singular word
plural word
bacterium
bacteria
fungus
fungi
animal
animals
1. Work in pairs. Talk in Kiswahili. Say each of these words out loud.
2. Read the following passage out loud in English and then say it in Kiswahili:
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The scientist took
one bacterium and
put into a tube
containing food. In
24 hours the
bacterium had
reproduced to form
many bacteria. The
scientist had to work
safely in case she
developed a bacterial
infection.
Figure 5.12 A scientist
working with bacteria
(‘Bacterial’ is an adjective word. A bacterial infection is a disease caused by
bacteria.)
10
Figure 5.13: What kingdoms do these organisms belong to?
11
Activity 5.8
Work in groups. Talk in Kiswahili.
1. Try to identify as many of the organisms as you can in figure 5.13.
2. Group the organisms into their kingdoms.
3. Talk to other groups. Do you agree with them?
4. How many groups did you get? List them.
5. How many organisms are there in each group?
12
Unit Four: Ranks of classification
Look again at the Russian dolls in Figure 5.7. We said that the largest doll contains all
of the smaller dolls. The largest doll is like the Kingdom and the smallest dolls are
called species. There are many species in a Kingdom.
Activity 5.9 How many species are there on Earth?
Glossary
discovered - vumbuliwa
extinct – toweka
sea - bahari
land - ardhi
including- pamoja na. . .
protect - kinga
rare – a-nadra
Scientists do not know how many species there are
on Earth. Many species have yet to be discovered.
Many species are becoming extinct before they can
be named.
In 2011, scientists said that they thought that 86% of
land species and 91% of sea species have not yet
been described. There may be as may as 9 million
species in the world (not including bacteria).
1. Work in pairs. Talk in Kiswahili about what these sentences mean.
2. Write down the number 9 million in numbers.
The table below shows how many species live in Tanzania.
3.
Add up the numbers
in the table to find
the total number of
species in Tanzania.
animal
number of species in Tanzania
insects
60 000
reptiles (snakes)
1 025
birds
1 000
mammals
364
Some species are only found in Tanzania and nowhere else in the world. The animals
and plants in Tanzania are very important. People travel to
Tanzania to see the animals and plants that live here.
4.
Talk in Kiswahili. This sunbird is found only in the
Udzungwa Mountains. It is found nowhere else in the
world. Why is it important to protect this rare species?
13
Figure 5.14 A
sunbird
Activity 5.10 What is your name and address?
What is your name? The name of your species is Homo sapiens. Homo means ‘human’,
sapiens means ‘wise’. Humans first appeared on Earth in East Africa. The earliest
human bones were found in near the Omo river in Ethiopia.
1.
Work in pairs. Talk in Kiswahili. Are you a wise human? Have you ever visited
Ethiopia? How far is Ethiopia from Tanzania? Did you know you are the children
of some of the oldest humans who ever lived on Earth?
Look at the diagram below. It shows all of the groups in the natural classification
system. Think of each group as a Russian doll in Figure 5.7. The largest group is the
Kingdom. It contains the most species.
Figure 5.15 The classification of Humans
2.
Work in pairs. Talk in Kiswahili. Look carefully at Figure 5.15. Use it to write
correct sentences.
Humans are
Primates
Vertebrates
Mammals
Animals
and so are
14
insects.
monkeys.
earthworms.
fish.
Humans are
grouped in the
Kingdom
Phylum
Order
Class
Primates
Vertebrates
Mammals
Animals
The full classification of the Human tells us a lot about our biology, and our position
in the living world. It is tells us both our name and our address.
The groups used to classify species are:
Kingdom, Phylum, Class, Order, Family, Genus, Species
These groups are called the ranks of classification.
3.
Work in pairs. Talk in Kiswahili. You need to remember the names of these
ranks of classification. Say the names out loud in order, until you remember
them.
This is how you say the words:
rank of classification
Kingdom
Phylum
Order
Class
Family
Genus
Species
how to say the word
King-dom
Fi-lum
Or-der
Kla-ss
Fam-il-ee
Gee-nus
Spee-sees
Some of these words change their spelling when they become plural.
one rank of classification
Kingdom
Phylum
Order
Class
Family
Genus
Species
4.
more than one rank of classification
Kingdoms
Phyla
Orders
Classes
Families
Genera
Species
Work in pairs. Talk in Kiswahili. Say out loud the singular and plural forms of
the ranks of classification.
15
Unit Five: Unicellular organisms
The world contains many odd and unusual organisms and many of them are found in
kingdom of the Protoctista. Members of the Protoctista are called protoctists. Many of
members of this group are unicellular. but some, like seaweeds, are multicellular.
Protoctists are not animals or plants, but often have characteristics of both.
Activity 5.11 What is Euglena like?
Euglena is small unicellular organism that lives in lakes and rivers. Euglena is about
0.06 mm in length. It is food for fish like Tilapia. This makes it useful. Figure 5.16
shows a photograph of Euglena.
Figure 5.16 Euglena is a protoctist
Euglena is like all members of the Protoctist Kingdom because it has a cell membrane
and a nucleus surrounded by a membrane. Euglena can make its own food in
photosynthesis.
1.
Work in pairs. Talk in Kiswahili. Say out loud the word Euglena. (‘You-glee-na’).
Euglena has chloroplasts. Name the kingdom that also contains organisms that
have cells with chloroplasts. What are chloroplasts for?
Euglena has a flagellum that is like a tail that moves from side to side. This helps it to
move. It has an eye spot that can see light so that Euglena can move towards or away
from things.
16
2.
Work in pairs. Talk in Kiswahili. Name the kingdom that also contains organisms
that can swim. Answer in English.
Sometimes, when there is not much light, Euglena can feed like an animal. Then
Euglena eats bacteria. This makes Euglena useful for treating sewage, which contains a
lot of bacteria.
3.
Work in pairs. Talk in Kiswahili. Write some sentences about Euglena.
a plant
Euglena is like
because it
an animal
can feed on
bacteria
has chloroplasts
Activity 5.12 What is Amoeba like?
Figure 5.17 Amoeba is a protoctist
Amoeba is small unicellular organism that lives in lakes and rivers. Amoeba is about 0.3
mm in length. Amoeba is like all members of the Protoctist Kingdom because it has a cell
membrane and a nucleus surrounded by a membrane.
Glossary
flow - jongea
liquid – kimiminika
particles chembechembe
The cytoplasm of Amoeba flows like a liquid,
allowing Amoeba to change its shape. It is
moving forward by growing pseudopodia.
17
Pseudopodia grow bigger and change shape. They can flow around bacteria and food
particles, drawing these particles into the body. You can see food particles in Figure 5.16.
When Amoeba feeds it takes water into its body. This water is removed from the body
by contractile vacuoles.
1.
Work in pairs. Talk in Kiswahili. Say out loud the word Amoeba. (‘Am-ee-ba’).
Write three sentences about how Amoeba moves, feeds and removes water.
moves
feeds
because it has
Amoeba
removes pseudopodia that
water
grow and move forwards.
draw food into the body.
have contractile vacuoles
to remove water
Activity 5.13 What is Paramecium like?
Paramecium is small unicellular organism that lives in lakes and rivers. Paramecium is
about 0.25 mm in length. Paramecium is like all members of the Protoctist Kingdom
because it has a cell membrane and a nucleus surrounded by a membrane.
Figure 5.18 Paramecium is a protoctist
Like Amoeba, it has many vacuoles, which are small spaces surrounded by membranes.
These sometimes contain food. Food enters Paramecium through its oral groove.
18
Paramecium has many small hairs on its surface called cilia. Cilia move from side to
side very quickly. This helps Paramecium move through the water.
1.
Work in pairs. Talk in Kiswahili. Say out loud the word Paramecium. (‘Para-meecee-um’).
Write three sentences about how Paramecium moves, feeds and removes water.
moves
feeds
Paramecium
because it has
removes
water
an oral groove .
cilia.
has contractile vacuoles.
Activity 5.14 What is Plasmodium like?
Plasmodium is small unicellular organism that lives inside anopheles mosquitoes,
sandflies and humans. Plasmodium is like all members of the Protoctist Kingdom
because it has a cell membrane and a nucleus surrounded by a membrane. Plasmodium is
0.01mm in length.
Figure 5.19 Plasmodium is a protoctist
Plasmodium spreads to humans when infected mosquitoes bite people. In humans,
Plasmodium lives inside the liver and red blood cells. It causes malaria. Malaria is a very
19
serious disease, which is difficult to treat with medicines.
The best way to reduce the risk of being infected is to avoid being bitten by infected
mosquitoes. Sleeping under mosquito netting can help this, because the mosquitoes tend
to fly in the evening and in the morning.
1.
Work in pairs. Talk in Kiswahili. Say out loud the word Plasmodium. (‘Plasmode-ee-um’).
Choose the three correct answers from the table below. Write three sentences that
correctly say where Plasmodium can live.
Plasmodium
2.
lives inside
human
human red
blood cells
tetse flies
human
kidney cells
mosquitoes
human liver
cells
Work in pairs. Talk in Kiswahili. Choose the correct answer from the table below.
Write one sentence that correctly says what causes malaria.
malaria
bad water
mosquitoes
testse flies
is caused by
infected
meat
bad luck
20
Activity 5.15 What are the advantages and
Glossary
advantages - faida
disadvantages – hasara
better – bora
harm - hatarisha
What are the advantages of the Protoctista?
This means ‘how do the Protoctista help us
to live better lives?’
disad
vanta
ges of
What are the disadvantages of the
Protoctista? This means ‘how do the
Protoctista harm our lives?’
the
Proto
ctista?
1.
Work in pairs. Talk in Kiswahili. Read through the pages about the Protoctista.
Think about advantages and disadvantages of the Protoctista. Choose the three
correct answers from the table below. Write six sentences that correctly say the
advantages and disadvantages of the Protoctista.
Euglena
causes malaria
and this is an
advantage.
makes oxygen
in
Paramecium photosynthesis
and this is a
is food for fish
disadvantage.
like Tilapia
eats bacteria in
Plasmodium
sewage
21
22
Unit Six: Bacteria
Activity 5.15 What are bacteria like?
Glossary
microscope - darubini
soil – udongo
air – hewa
water – maji
slimy - teleza
1.
Bacteria are found in the Monera kingdom. Bacteria are
the smallest living organisms and can only be seen with a
microscope. They are about 0.005 mm in length. They are
unicellular organisms, because they only have one cell.
Bacteria are found everywhere. They are found in the
air, water and soil.
Work in pairs. Talk in Kiswahili. Write sentences about bacteria.
unicellular
seen with a
microscope
Bacteria are
because
found
everywhere
not animals or
plants
they are in
the kingdom
Monera.
they are
0.005 mm in
length.
found in the
air, water
and soil.
are single
cells.
Bacteria have a simpler kind of cell than animals, plants or fungi.
Figure 5.20 Bacteria have simple cells
23
Bacteria have a cell wall and cytoplasm. The cell wall gives the bacteria a shape and
protects the cytoplasm from damage.
Inside the cytoplasm is one large circular chromosome that contains genetic material that
controls the growth of the cell. Plasmids are small circular loops of genetic material that
are found in the cytoplasm.
Some bacteria have one flagellum (or more than one flagella). Flagella help bacteria to
move. In some bacteria the cell walls are covered with a slimy layer called the capsule.
Look at Figure 5.21. Bacteria have several different shapes.
Figure 5.21 Bacteria have different shapes
2.
Work in pairs. Talk in Kiswahili. Write sentences about bacteria.
move
Bacteria
are protected
from damage
control their
growth
can be slimy
they have
capsids.
using flagella.
because
24
they have cell
walls.
with their
large circular
chromosomes.
Activity 5.15 What are the advantages and disadvantages of bacteria?
Glossary
advantages - faida
disadvantages – hasara
infections - maambukizi
diarrhea – kuharisha
What are the advantages of bacteria? This
means ‘how do bacteria help us to live
better lives?’
What are the disadvantages of bacteria?
This means ‘how do bacteria harm our
lives?’
Some bacteria can cause diseases. If we eat fruits without washing them first, or drink
water that is not treated, bacteria might infect us. Also, bacteria can get into our body
through the skin or the air that we breathe.
The diseases caused by bacteria include: typhoid, pneumonia, gonorrhea, tetanus, urinary
tract infections (UTI), cholera, diarrhea, tuberculosis, syphilis.
Cooked food or meat can spoil and make a bad smell. This is due to bacteria. So bacteria
are very small but they are very destructive.
Some bacteria are harmful. Bacteria are used to make butter and cheese. Other bacteria
make vinegar.
Bacteria in the soil help to break down dead plants and animals to release nutrients into
the soil. Some bacteria in the soil can turn nitrogen gas in the air into nitrate fertilizer to
help plants to grow.
There are many bacteria in human intestines that help in breaking down the food we eat.
They can also make important vitamins that we need to stay healthy.
1.
Work in pairs. Talk in Kiswahili. Think about advantages and disadvantages of
bacteria. Choose the three correct answers from the table below. Write six
sentences that correctly say the advantages and disadvantages of the Protoctista.
25
cause diseases
Bacteria
help to make
butter and
cheese
help to make
vinegar
help to break
down dead
plants and
animals
26
and this is an
advantage.
and this is a
disadvantage.
Unit Seven: Viruses
Glossary
Viruses are not alive. Viruses do not feed, breathe or
grow like living organisms do. Viruses reproduce by
infecting and entering the cells of a living organism. The
new viruses kill the living cells when they escape. The
viruses then infect new cells. The number of viruses can
increase very quickly. This is reproduction.
infect alive feed –
breathe grow –
escape –
type –
We talk of having one virus, but many viruses.
Viruses are very small. They are about 0.0005mm in length. They can only be seen
with a powerful microscope known as electron microscope. However, we can feel
the effects of viruses. Most viruses cause diseases such as flu, measles, mumps,
small pox, chicken pox, polio and AIDS.
1.
Work in pairs. Talk in Kiswahili. Answer in English. Have you ever been ill with
a disease caused by a virus? How did it make you feel?
Write sentences about viruses.
are seen with
an electron
microscope
unicellular
cause diseases
Viruses
because
are not alive
infect living
cells
27
because they
do not feed,
breathe or
grow.
they are
0.0005 mm
in length.
they
reproduce
inside living
cells.
kill cells.
Activity 5.16 What are viruses like?
Glossary
inject coat material -
Each species of virus infects only one type of host cells.
The virus HIV infects one type of white blood cell in
humans. It does not infect any other type of human cell.
Figure 5.22 This virus infects cells of bacteria
Figure 5.22 shows a virus that infects cells of bacteria. It has an outer coat made of
protein called a capsid. Inside the virus is genetic material.
The virus attaches itself to the bacterial cell. It injects the genetic material into the bacterial
cell. The genetic material makes the bacterial cell reproduce millions of new viruses.
1.
Work in pairs. Talk in Kiswahili. Write two sentences about viruses.
has a protein
coat
A virus
that
has genetic
material
28
makes the
cell reproduce
millions of
new viruses.
is called a
capsid.
Activity 5.17 What are the advantages and disadvantages of viruses?
Glossary
advantages - faida
disadvantages – hasara
better – bora
harm – hatarisha
controversial –
epidemic -
What are the advantages of viruses? This
means ‘how do viruses help us to live
better lives?’
What are the disadvantages of viruses?
This means ‘how do viruses harm our
lives?’
Viruses that kill bacteria are useful, because they can sometimes help people to control
diseases caused by bacteria. This is a very controversial use of viruses, and many
countries do not allow it to take place.
Scientists use viruses a lot in their work. Viruses can be used to carry useful genetic
material into cells. This is called genetic engineering.
Some viruses that cause disease are used to make vaccines to protect people from those
diseases.
Viruses are often harmful. Because they reproduce very fast, they can cause epidemics
that can affect whole countries. Their diseases can be difficult to cure. Antibiotic
medicines cannot be used to cure infections caused by viruses.
29
1.
Work in pairs. Talk in Kiswahili. Write two sentences about viruses.
cause diseases
Viruses
help scientists
to make
vaccines
help scientists
to carry useful
genetic
material into
cells.
reproduce
quickly and
can cause
epidemics
30
and this is an
advantage.
and this is a
disadvantage.