Lesson video

Hi everyone.

I'm Mrs. Horan.

I'm really pleased you've come to join me for some science learning today.

Today's lesson is part of the unit on why we group and classify things.

The lesson is called "Grouping micro-organisms".

And we are going to be looking at ways we can classify tiny living things.

The outcome for our lesson today is to group micro-organisms based on similarities and differences.

This lesson builds on what you already know about classifying living things, using their observable characteristics, and as part of our big learning question, "Why are there similarities and differences between living things?

" These are the keywords that we're going to be focusing on today.

Micro-organism.

Bacteria.

Virus.

And, fungi.

Some of these words might be new to you and you might be familiar with some of them already.

We're gonna look at each one in detail when we come to it in the lesson, so we'll have a really good understanding of them all by the time we finish.

Here are some explanations of the keywords.

We're not going to look at them closely now because each one will be explained as we come to it during the lesson here, so that you can come back to them at any point in the lesson if you need to check anything or if you want a reminder of what one of the words means.

Our lesson today comes in two parts.

Let's get started with the first part, type of micro-organism.

Can you remember the names for these groups of living things?

In the first group of living things, we have some grass, a yellow kerria flower, a blackberry bush, and some moss.

Can you remember the name for this group of living things?

Great.

These are all plants.

In our next group we have a slug, a crab, a rabbit, and a chameleon.

What group do all of these living things belong to?

Yep, this one is animals.

And finally we have a couple of types of bacteria, a virus, and some fungi.

Can you remember the name for this group of living things?

These living things are all part of the micro-organisms group.

You can see that word micro-organisms is a keyword for today.

You might remember that micro-organisms are very tiny living things.

They're so small in fact that we usually can't see them with just our eyes and need a microscope to get a good look at them.

Let's think about grouping living things even further.

Plants can be grouped into flowering and non-flowering plants.

You can see we have an example of a flowering plant here, the lovely yellow kerria flower, and a non-flowering plant, which is a type of moss.

Animals can be grouped into vertebrates and invertebrates, then further classified into groups such as reptiles, mollusks, and crustaceans.

We have an example of a reptile, a mollusk and a crustacean here.

Micro-organisms can be further classified into groups based on their observable characteristics, just like plants and animals.

These groups include bacteria, viruses and fungi.

Scientists group micro-organisms to make it easier to identify, name and learn about them.

Let's do a quick check for understanding and see how we're getting on so far.

Which of these groups are micro-organisms?

We have a, fungi, b, insects, c, arachnids, d, viruses, and e, bacteria.

Pause the video here to have a think and make your choices.

Let's see how we did.

Fungi, viruses and bacteria are all types of micro-organisms.

Insects and arachnids are invertebrate animals, not micro-organisms.

Let's find out more about each of the different types of micro-organisms starting with bacteria.

Bacteria is one of our keywords for today.

When we use the word bacteria, we're talking about the plural.

The word bacteria is for when we have more than one of them.

A singular form is bacterium, but that one doesn't get used very often because we usually talk about more than one of them at a time.

Bacteria can be found almost everywhere on earth, including in freezing Arctic snow and inside scorching volcanoes.

There are very, very few places on earth that bacteria cannot survive.

They're incredibly hardy little things.

Bacteria can be found in air, water, soil, and even in loving things.

That includes plants and animals and some of them can even live inside other micro-organisms.

Bacteria are usually rod shaped, round or spiral shaped.

Some have a flagella or tail.

You can see some examples of bacteria in the pictures here.

Of course, these are all pictures taken using microscopes because we can't see bacteria using just our eyes.

They're much too small.

Most types of bacteria have a shape, something like the ones in these pictures.

Looking at the shape of a micro-organism is one piece of evidence scientists can gather when they're classified.

Bacteria take in nutrients through their outer surface.

They don't have miles like us, so the nutrients they need are absorbed through their outer surface, a bit like how the roots of plants absorb water.

They reproduce by dividing in half.

Each of these new bacteria then divides in half again and again.

They can increase in number and grow very quickly in a short time using this process.

Our bodies are full of bacteria, most of which don't do us any harm, and many even help us.

They live inside our digestive system, our lungs, and on our skin.

Right now there are billions of bacteria living inside you.

In fact, there are more bacteria in your body than there are humans on the planet.

Most of them are just minding their own business and many of them are actually quite useful.

There are bacteria in your intestines that can kill any harmful micro-organisms that make their way into your body and some that help us to digest food.

Not all bacteria are helpful or harmless, though.

Some of them are harmful.

When these harmful bacteria enter our bodies, they can cause damage or make us unwell.

Food poisoning, tooth decay and pneumonia can be caused by bacteria.

Have you ever felt that fuzzy stuff on your teeth when you haven't been brushed for a few hours or you've eaten something sugary?

That's made by the bacteria that are living in your mouth?

That stuff can cause tooth decay, which is why it's important that we brush our teeth regularly to remove it.

Our immune system can fight off many bacterial illnesses.

That means that we can get better from them without needing to see a doctor or take medicine.

Some more serious illnesses caused by bacteria can be treated with antibiotics.

Have you ever had antibiotics before?

You can only get 'em from the doctor and they're commonly used to treat things like ear, throat and chest infections.

Time for another quick check for understanding to see how we're doing.

Which of these statements about bacteria are not true?

A, all bacteria make us ill, b, bacteria live almost everywhere, including inside living things, c, bacteria only live in dirty places, d, bacteria are living things and e, bacteria can be different shapes?

Pause the video here to have a think about this and come back when you've decided which of those statements are not true.

Okay, let's see how we did.

The statements that are not true are a and c.

We know that not all bacteria make us ill because there are lots of them in our bodies and the air around us right now and we're not all ill.

We know that bacteria don't only live in dirty places because in fact, they live almost everywhere.

You're surrounded by them right now.

They do of course, live in dirty places too, but they don't only live in dirty places.

Let's find out more about viruses next.

Virus is another keyword, and this one has a much more simple singular and plural form than bacteria.

We say one virus or many viruses.

Viruses are even smaller than bacteria.

Around 500 million of the virus that causes a cold could fit onto the head of a pig.

Because they're so much smaller, there are many types of virus that can live inside bacteria.

There can be many different shapes including spiky and round and insect like shapes.

Just like our pictures of bacteria, these are extreme closeups of viruses as they would look under a powerful microscope 'cause they're much too small for us to see them with the naked eye.

That one in the middle that looks a bit like a spider wearing a space helmet is a type of virus called a bacteriophage, and those are the ones that can get inside bacteria.

Viruses can only survive inside other living things.

They can be found inside plants, animals, and even bacteria.

Often viruses are harmful to living things.

Chicken pox, the flu and measles are all caused by viruses.

We have vaccinations to protect us from a lot of the illnesses caused by viruses because they can be quite harmful.

You might have had vaccinations yourself to protect you from the flu, COVID-19 or mumps.

Viruses have been tricky for scientists to classify because they only have some of the characteristics of living things.

The natural world is weird and wonderful and we often find things that can't be neatly grouped because their characteristics don't quite fit in with the other living things in that group.

Viruses are one of those things.

So we know all living things can reproduce.

Animals have babies, plants use seeds or spores to reproduce and as we've just learned, bacteria can reproduce by dividing themselves in half.

What about viruses then?

Viruses can reproduce, but only when they are inside another living thing.

They cannot reproduce on their own.

Because of this, many scientists do not consider viruses to be living things.

What do you think?

It's a very tricky question to think about.

Let's have another check for understanding.

Read this statement and decide whether you think it's true or false.

Scientists all agree that viruses are living things.

What do you think?

True or false?

We know that statement is false.

Not all scientists agree that viruses are living things.

Now, can you justify why it is false?

Is it because a, viruses cannot reproduce on their own like all other living things, or is it b, because viruses are too small to be living things?

So that one is false because viruses cannot reproduce on their own like all of the living things.

This makes them very tricky to classify because they have some of the characteristics of living things, but not all of them.

The final type of micro-organisms we're going to be looking at today is fungi.

This is another keyword with tricky plural and singular forms.

So if we're talking about just one, it's called a fungus.

More than one are fungi.

A bit like we say one cactus, and two cacti, one fungus, two fungi.

Fungi have a more complicated structure than bacteria and viruses.

Under a microscope, they're usually long and thin with branches.

You can see some fungi under a microscope in the first picture there.

They can go large enough for us to see with the naked eye.

There are some types of fungi that we don't need a microscope to see.

Mushrooms and mold that forms on food are examples of fungi.

You probably have seen both of these before without using the microscope.

Most fungi take in nutrients through microscopic threads called hyphae.

Can you see that word there?

It's pronounced hyphae.

You can see some hyphae under a microscope in the picture there.

Fungi feed on almost anything organic.

This means anything that is or was once alive.

That includes plants and animals as well as products we can make from living things such as wooden furniture, paper made from trees or clothing made from wool.

Many fungi reproduce using spores.

Fungi release these very tiny spores into the environment and if the spores land in a damp place, the right conditions, they can grow into a new fungus.

There's a really cool way you can see this for yourself actually.

If you leave mushrooms on white paper for a day or two, you can observe the clusters of spores that have been released.

If you're going to try this yourself, make sure you use mushrooms that you bought in a supermarket or grocers so we know they're safe to handle.

We should never pick wild mushrooms 'cause there are lots of really harmful, poisonous ones.

When you've got your safe mushrooms, slice off the stem so the tops sit down flat on the paper and leave them for about a day or so.

It's a good idea to cover them with a box so the tiny spores don't get blown away when they're released.

After a day or so has passed, you'll be able to remove your mushrooms and see the spores.

Fungi can also reproduce by breaking into pieces, which can then become new organisms or by growing buds on their surface.

Jun has been learning about fungi just like you, and he says, "Mushrooms grow out of the ground like plants and they reproduce with spores like non-flowering plants do.

I think mushrooms are plants.

" Do you agree?

You might want to pause the video here for a bit of thinking time or to talk about your ideas with a partner.

And what did you think?

In this case, Jun is not correct, but this is a really common mistake that lots of people make because mushrooms do look a bit like plants and some of them reproduce in a similar way.

However, plants make their own food using a process called photosynthesis.

Fungi including mushrooms cannot do this.

Unlike plants, mushrooms get their nutrition from their surroundings so they're not plants.

A bit like bacteria, some types of fungi live in our bodies without causing us any harm.

But some types can make us ill if they get into our body.

They can cause fungal infections on our skin or make us very unwell if we breathe them in or eat them.

This is why we should never eat moldy food because the fungi that cause mold are harmful to humans.

Time for a couple more check-ins on our understanding.

Now first, you have to decide whether each of these statements is true sometimes, always, or never.

So we have a, fungi can be safely eaten by humans, b, fungi are plants, c, fungi reproduces spores and d, fungi feed on organic matter.

Pause the video here to decide whether you think each of these statements is sometimes, always or never true, and come back when you're ready.

Let's see how we did.

So a, fungi can be safely eaten by humans.

That is sometimes true.

We can eat sometimes in mushrooms like chestnut and butter mushrooms which are fungi, but we can't eat mold and some types of mushrooms are very poisonous.

B, fungi or plants.

This one is never true.

Plants make their own food by photosynthesis, whereas fungi get their nutrients from organic matter around them.

C, fungi reproduce using spores.

This is sometimes true, some types of fungi do and some types reproduced by breaking into pieces or by growing buds on their surface.

And finally, d, fungi feed on organic matter.

This one is always true.

That's how they get their nutrients.

And for this one, you need to make some observations of the micro-organisms in the pictures and decide whether they are bacteria, viruses, or fungi.

Use the shape of the micro-organisms to help you decide.

So you want to look back at the slides with pictures of the different types if you are not sure.

We have three to classify.

We have a, candida, b, chickenpox and c, E.

coli.

Pause the video now to have a go.

So we had candida, which is fungi.

We can tell because it has thin branches.

B, which was chickenpox, which is a virus.

We can tell this is a virus because it looks like a spiky ball.

And c, E.

coli is a type of bacteria.

We can tell they are bacteria because of their long, thin shape.

Now it's time for you to imply this knowledge to a practice task.

Sort the micro-organisms into the table.

The table is on the next slide for you.

Use the shape of each micro-organisms to help you decide.

The micro-organisms we have to classify are candida, mucor mold, influenza, staphylococcus, shingles, and salmonella.

Just like before, you can take a look back at the slides with pictures of the different types to help you if you need to.

Let's take a quick look at the table before you get started.

Here's your table.

It's nice and simple with a column each for the bacteria, viruses, and fungi.

Pause the video now to make your observations in the micro-organisms and complete the table.

Welcome back.

Here we have the completed table.

Let's see how you did.

In the bacteria column, we should have staphylococcus and salmonella.

In the viruses column, we need shingles and influenza, which is often called flu.

And in the fungi column, we have candida and Mucor mold.

Time for the second part of our lesson now.

Helpful and harmful micro-organisms.

Our Izzy is not having a very good day today.

She says, "The flu virus made me ill.

Bacteria in my mouth can damage my teeth and I couldn't have toast for breakfast today because there was mold on my bread.

I think micro-organisms are all bad.

" Do you agree with her?

What do you think?

So many micro-organisms are harmful to living things, but there are also many that are helpful.

Some of the bacteria that live inside our intestines help us to digest food and others kill harmful micro-organisms that enter our digestive system.

Those are both really useful to us.

Micro-organisms living in soil break down or decompose organic matter such as dead plants and animals.

This releases nutrients into the soil and makes them available to other plants growing in the ground nearby.

Bacteria and fungi can both be decomposers.

Decomposers are useful for agriculture or farming.

Some farmers even add helpful microbes directly to the soil to encourage healthy plant growth.

Scientists have even recently identified the type of bacteria that can decompose plastic.

That's amazing because normally micro-organisms can only decompose things that are organic, mainly things that have come from living things.

Plastic is human made and so it doesn't break down or decompose, which is really causing problems for the environment and the plants and animals living in it.

Micro-organisms like this could be very useful in future to help break down the large amounts of plastic waste that have been created.

Let's have another check for understanding.

Which types of micro-organisms are useful for decomposing organic matter?

Your choices are a, bacteria, b, viruses, and c, fungi.

Pause the video here to have a think and decide which ones are decomposers.

So the micro-organisms that are useful for breaking down or decomposing organic matter are a, bacteria and c, fungi.

There are many kinds of foods we have, thanks to micro-organisms.

There are some types of fungi that we can eat like Portobello mushrooms and truffles.

You can see some truffles in the pictures there.

Truffles are considered to be a delicacy in many places and they can be very expensive to get hold of.

It's important to remember though that even though we can eat some types of fungi, many types of fungi are harmful and some are even deadly.

You must never eat mushrooms found in the wild in case they're poisonous.

A type of fungi called yeast can be used for fermentation, which is used in the production of lots of foods.

Fermentation is when yeast breaks down sugars and creates other substances.

Bread, cheese, yogurt, and soy sauce are some of the foods that are made with fermentation.

Time for another question.

Which of these foods are produced with fermentation by micro-organisms?

A, cheese, b, bananas, c, bread, and d, pasta.

What do you think?

Both cheese and bread are produced with fermentation done by micro-organisms.

Micro-organisms may sometimes cause disease, but there are many types that help to treat or prevent disease.

Micro-organisms are used in the production of many antibiotics which can be used to treat bacterial illnesses.

They're also used to create vaccines which can help prevent us from catching and spreading diseases.

If you've ever had a vaccination before, perhaps the flu, COVID, measles or mumps, you have micro-organisms to thank for that.

It's important for scientists to classify micro-organisms because it can help 'em to understand more about how they can be used.

It can also help us to learn more about how to prevent harm from micro-organisms.

For example, if a new micro-organisms is discovered, scientists can get some idea of how it might be helpful or harmful by classifying it and seeing which other micro-organisms it's similar to.

COVID-19 is a disease caused by a type of virus called a coronavirus.

We often refer to COVID-19 as the coronavirus, but it was in fact just a new type of a virus that already existed.

Coronaviruses have existed for many years, so scientists already had lots of data about the structure and lifecycle of this type of virus.

When the COVID-19 pandemic spread across the world in 2020, scientists were able to use what they knew about other viruses in the coronavirus family to quickly give advice on slowing the spread of this new type and develop a vaccine.

One more check for understanding now before our final practice task.

Why do scientists classify micro-organisms?

Is it a, to help them invent new micro-organisms, b, to find out what they're called, or c, to understand how they can be helpful or harmful?

The correct answer is c, to help understand how they could be helpful or harmful.

Now we have two practice tasks to round off the lesson.

In the first one, you need to take a good look at this photo of Sam's lunch.

How might micro-organisms have been involved in the production of Sam's cheese and tomato sandwich?

List as many as you can think of.

Think about all the different ingredients and how micro-organisms might have been involved in their creation.

Pause the video here to think of as many as you can.

Here are the ideas Sam had.

"The bread and cheese have been made using fermentation, which is done by micro-organisms.

The farmer who grew the lettuce and tomatoes might have added micro-organisms to the soil to help them grow well.

" Did you get all of those?

Do you have any other ideas?

For our last task that we have table to complete with some information.

Aisha has carried out some research into micro-organisms.

Your job is to read the information she has found and complete the table.

The first column is for the name of each micro-organisms.

The second is for the type, so is it the bacteria, virus or fungi.

The third column is for the appearance of the micro-organisms.

so what does it look like.

You can either write a really short description here, for example, round with a tail, or you could draw a small diagram if you prefer.

And the fourth column is for putting information about whether it is helpful or harmful.

Let's take a look at Aisha's research.

I'll read it through now so you can listen and read along if you want to.

And then you'll probably need to go back and pause the video on each one so you can check over each one for any details you might have missed.

Let's have a look at the first article Aisha found.

"Varicella-zoster.

Pretty much everyone has heard of chickenpox and most people have even had it themselves, but do you know what causes it?

Chickenpox is caused by a type of virus called varicella-zoster.

This same virus can also cause shingles, but usually only just so in adults.

These tiny microbes which look like spiky balls are spread from person to person through the saliva, mucus, or blisters of an infected person.

Most people only suffer with chickenpox caused by this virus once though as their immune systems learn how to fight it and are able to prevent it reproducing and spreading if it enters the body again.

" Our next article is about a micro-organism called Lactococci.

Lactococci might sound like an exotic and unusual word, but they can be found in a certain part of most supermarkets in the dairy section.

These bacteria play a really important role in the production of cheese and yogurt.

You may even have eaten them yourself.

Many of the bacteria you use for cheese making die off in the earliest stages of the process, but there are some types that survive and contribute to the flavor of cheeses like Parmesan and Gruyère.

Under a microscope, they look like tiny round blobs with a line around their middle and have a relatively simple structure.

As you probably guessed, these micro-organisms are not harmful to humans as well as most animals.

And our third and final article is about penicillium, and this one's a little longer than the other two.

Let's take a look.

"Penicillin is a common antibiotic used to treat all sorts of different bacterial infections with a really surprising origin story.

In 1928, a scientist called Dr. Alexander Fleming had been working with different bacteria and took a break to go on holiday.

When he returned, he found mold growing in one of his Petri dishes and that this mold seemed to be stopping the bacteria around it from growing.

He investigated this fungus and found that it produced a self-defense chemical that could kill bacteria.

This was the beginning of a long journey to produce something using this harmful penicillium mold that could kill unwanted bacteria in humans and treat disease.

It was many years before they were successful and able to extract pure penicillin.

In modern times, penicillin is often used to treat bacterial infections and save countless lives, all as a result of Dr. Fleming leaving out his dirty dishes.

" And there's an image there of what penicillium fungus looks like under a microscope.

So pause the video here to have a go at completing your table.

All the information you need is here, so you should be able to fill every section and then come back when you're finished.

How did you find that?

I dunno about you, but I've learned a lot of micro-organisms here.

Isn't it amazing that penicillin and antibiotic that we use all the time was discovered by accident?

Let's take a look at what we should have in the table.

So the first row, we have the varicella-zoster virus.

The type of micro-organisms is virus, its appearance is spiky balls and it is harmful.

It causes chickenpox and shingles in humans.

The second row we have Lactococci, which is a type of bacteria.

Its appearance is round with a line around the middle and it is helpful.

It's used to make cheese and yogurt.

And the third row we have Penicillium.

It's a fungus and it's long and thin with finger-like branches.

That one is both helpful and harmful.

So it's harmful in general, but helpful penicillin can be extracted from it.

We've come to the end of today's lesson, so let's take a look at our key learning from today.

Scientists group micro-organisms to make it easier to identify, name and learn about them.

Bacteria, viruses and fungi are groups of micro-organisms.

Micro-organisms can be harmful or helpful.

Classifying micro-organisms into groups helps us to understand their uses and treatments.

Thank you for coming to join me today to learn about different types of micro-organisms.

We've learned so much and got to grips with some really complicated stuff today.

So you should be proud of all your hard work.

I look forward to seeing you again next time.