Microorganisms
Microorganisms, or microbes for short, are tiny living organisms that can only be seen through a microscope. They are not animals or plants, but are their own separate group.
Microorganisms come in different shapes and sizes and there are three main types:
- Bacteria – These are single-celled organisms. Some bacteria can help us, like the ones in our gut that help us digest food. Others can make us sick.
- Viruses – Even smaller than bacteria, viruses can only live inside the cells of other organisms. They can cause illnesses like flu or colds.
- Fungi – This group includes things like mould and yeast. Yeast is used to make bread rise, while some types of mould can spoil food.
Watch: What is a microorganism?
Fran: Plants, animals and humans are individual living creatures or organisms.
Now some organisms are so tiny, that we need one of these to see them.
These are microorganisms.
There are a few different types of microorganism.
Bacteria are single celled microorganisms and they are found almost everywhere on earth, even inside our bodies.
They can be helpful in digesting food but sometimes harmful and they can make us sick.
Here I have a fungus and a fungus is a microorganism that can be single-celled or multi-celled.
Let's have a look at this one.
It's like a tiny blue bird's nest.
Let's see what our investigator has found out about microorganisms.
Child: I'm hunting for fungi.
Over here!
You have to be careful.
We do eat some fungi, like mushrooms from the shop.
Lots of them can make you sick or even kill you.
So it's best not to touch them.
Fungi feed on dead organic matter, like these leaves.
Then nutrients from the fungi seep back into the soil and the air, creating healthy soil.
It's a natural recycler.
Fran: That is right!
Fungi gets rid of dead matter and turns it into something useful, like compost.
We call this process decomposition.
And it's also what happens to our food when it goes off.
Light and moisture can have a big effect on how quickly microorganisms grow and how quickly our food decomposes.
Three days ago, I put two pieces of bread each in two sealable bags.
I sprayed one with water and left it in a dark place. And the other I left dry and put it in a sunny place.
Let's see what happened.
You can see the one in moist conditions has started to grow mould and that's because fungi love dark, damp conditions.
So, , microorganisms are everywhere, so make sure you wash your hands regularly and keep your food in the right conditions.
I know I will!
Yuck.
Fascinating facts
Microorganisms can also be called microbes.
There are more species of bacteria than any other life form on Earth. Scientist believe that over three quarters of all species of life on Earth may be bacteria!
There are over 100,000 recognised species of mould on our planet.
We have bacteria living inside our stomachs and intestines, it helps us to digest and process food.
Penicillium mould is the source of antibiotic penicillin, which has saved millions of lives since it was discovered.
Some species of fungus can glow in the dark.
If we lined up all of the bacteria on Earth, it would stretch to around 10 billion light years across, that's as far as here to the edge of the known Universe.
Watch: Different types of microorganism
Find out about the different kinds of microorganisms.
Narrator: It wasn’t until someone invented the microscope in the 18th century, that people could start looking at very very tiny things known as microorganisms.
They discovered that there is a whole world of tiny creatures… called viruses and bacteria. Often we call them germs.
Sometimes germs can make us unwell, but we do need some germs to keep us healthy. Without them we wouldn’t be able to digest food.
They are inside us… and all around us. In fact, if they weren’t in the soil, food wouldn’t be able to grow.
Microorganisms may be tiny, but they play a very big role on planet earth.
Slideshow: What are microorganisms?
Image caption, Bacteria
Bacteria are a microorganism which can break down plants to release nutrients into the soil. They can also make animals ill.
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Did you know?
Bacteria are the earliest known life forms on Earth, they have been around for at least 3.5 billion years.
The earliest land plants on Earth only appeared around 500 million years ago, with the first dinosaurs appearing around 240 million years ago.
Sir Alexander Fleming and the discovery of penicillin
Sir Alexander Fleming (1881-1955) was a Scottish physician and microbiologist.
The British scientist Sir Alexander Fleming developed the drug penicillin by accident, while studying bacteria in 1928.
He had left plates of bacteria growing in his laboratory in St Mary's Hospital, London while he was on holiday, and when he returned various types of mould had grown on them. On one of those plates a mould had killed the bacteria.
Now known as the antibiotic drug penicillin, Fleming's discovery is used to fight lots of illnesses and has saved millions of lives.
Fleming was knighted for his scientific achievements in 1944, and won the Nobel Prize in Physiology or Medicine in 1945.
Important words
Antibiotic – A type of medicine that can kill bacteria and stop it from spreading.
Bacteria – Bacteria are made up of just one cell and bacteria are everywhere, they live in soil, on your skin and even in your gut.
Fungi – Fungi take in dead matter and help turn it back into nutrients for the soil.
Microorganisms – Tiny living things that are so small that they cannot be seen without a microscope. Microorganisms include bacteria, viruses, algae and fungi.
Viruses – Tiny germs that are much smaller than bacteria. Unlike most living things, viruses cannot survive on their own and need to invade a host cell to grow and multiply.
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