Year 6 Science: Micro-organisms
Part of the Year 6 Science classifying living things chapter. Chapter overview · whole chapter on one page
Micro-organisms
Micro-organisms are living things that are too small to see clearly without a microscope. Many micro-organisms are single-celled, which means each one is made of one cell.
Bacteria are single-celled micro-organisms. An amoeba is another single-celled micro-organism, found in pond water. Both move, grow and reproduce, which shows they are alive.
Pictures of micro-organisms are drawn much bigger than they really are, so that we can see their shapes.
Key ideas
- Micro-organisms are living things too small to see clearly without a microscope.
- Many micro-organisms are single-celled, made of one cell.
- Bacteria and amoebas are examples of micro-organisms.
- Micro-organisms are a broad group of their own.
Method. Use the definition of micro-organisms.
- Read the definition. Micro-organisms are living things too small to see clearly without a microscope.too small
- Decide. So micro-organisms are too small to see clearly with the eye alone.yes
- Write the answer. yes
Check. A microscope is needed to see them clearly. ✓
Method. Think about what makes very small things bigger.
- Read the idea. We need an instrument that makes very small things look larger.larger
- Name the instrument. That instrument is a microscope.microscope
- Write the answer. microscope
Check. A magnifying glass is not strong enough for most micro-organisms. ✓
Method. Think about a single-celled micro-organism.
- Read the description. An amoeba is a single-celled micro-organism.single-celled
- Decide. So an amoeba is made of one cell, and the answer is yes.yes
- Write the answer. yes
Check. Bacteria and amoebas are both single-celled. ✓
Watch out
Watch out: micro-organisms are not plants. Many are not plants or animals, and they form a broad group of their own.
Exam tip
Exam tip. Use the word single-celled when you describe micro-organisms, and say that a microscope is needed to see them clearly.
Try it (with your teacher, or a grown-up at home). With a grown-up, look at a few drops of pond water or tap water under a classroom microscope, if one is available. Draw what you see, and count how many moving things you can see in one drop. Wash your hands afterwards. Do not taste or drink pond water.
Exercise 2D Micro-organisms
Method. Read the definition.
- Read the definition. Micro-organisms are too small to see clearly without a microscope.too small
- Decide. So the answer is yes.yes
- Write the answer. yes
Check. That is why they need a microscope. ✓
Method. Think about the instrument that makes very small things look larger.
- Name the instrument. A microscope makes very small things look larger.larger
- Write the answer. So we use a microscope.microscope
- Write the answer. microscope
Check. A microscope lets us see tiny living things. ✓
Method. Look at the picture in section 2.4.
- Read the labels. The labels show a bacterium and an amoeba.bacterium, amoeba
- Write one name. So the answer is bacterium or amoeba.bacterium
- Write the answer. Accept bacterium or amoeba.
Check. Both are micro-organisms. ✓
Method. Read the description of an amoeba.
- Read the description. An amoeba is a single-celled micro-organism.single-celled
- Decide. So the answer is yes.yes
- Write the answer. yes
Check. Single-celled means made of one cell. ✓
Method. Read the description of bacteria.
- Read the description. Bacteria are single-celled micro-organisms.single-celled
- Decide. So bacteria are not made of many cells; the answer is no.no
- Write the answer. no
Check. Many cells would make an organism bigger. ✓
Method. Read the note under the picture.
- Read the note. The note says both are shown much bigger than they really are.much bigger
- Decide. So they are not drawn at their real size.no
- Write the answer. no
Check. Scientists draw micro-organisms bigger so we can see their shapes. ✓
Method. Use the broad groups.
- Read the groups. Micro-organisms form their own broad group, separate from plants and animals.own group
- Decide. So micro-organisms are not all plants, and Ali is not right.no
- Write the answer. no
Check. Micro-organisms are a separate group. ✓
Method. Use the definition of micro-organisms.
- Read the definition. Micro-organisms are too small to see clearly without a microscope.microscope
- Decide. So Ruby is not right.no
- Write the answer. no
Check. Without a microscope, most micro-organisms cannot be seen clearly. ✓
Method. Look at what both have in common.
- Compare. Both are single-celled and too small to see clearly without a microscope.both
- Write the group. So both belong to the micro-organisms group.micro-organisms
- Write the answer. micro-organisms
Check. They share the same broad group. ✓
Method. Think about what living things do.
- Think about living things. Living things move, grow and reproduce.move, grow, reproduce
- Pick one. A micro-organism can move, grow or reproduce.move
- Write the answer. Accept any one of: move, grow, reproduce.
Check. These actions show a micro-organism is alive. ✓
Method. Think about how scientists study small things.
- Think about the microscope. A microscope shows the shape and features of micro-organisms.shape
- Think about the sorting. Features seen under the microscope can be compared and used to group micro-organisms.compare
- Write the answer. Accept any sentence that says micro-organisms can be studied under a microscope, and their features can be compared.
Check. Observable features under a microscope can be used like any other characteristic. ✓
Method. Use the features of living things.
- Think about size. Size does not decide whether something is alive.size
- Think about features. A micro-organism can move, grow and reproduce, which are features of living things.features
- Write the answer. Accept any sentence that says it can move, grow or reproduce, which are features of living things, whatever its size.
Check. Living things share features whatever their size. ✓
Method. Think about what the drop contains.
- Think about the drop. A drop of pond water can contain many small living things.many
- Think about the microscope. A microscope makes them large enough to see their shapes.microscope
- Write the answer. Accept any sentence that says a drop of pond water can contain many micro-organisms that are too small to see clearly by eye.
Check. Looking closely is how many micro-organisms are studied. ✓