Hello and welcome to today's lesson from the unit introduction to food chains.

This lesson is called roles within food chains.

By the end of today's lesson, you'll be able to create food chains and talk about different roles played by plants and animals.

Hello, my name's Mr Loudin and I can't wait to learn science with you today.

I know if you concentrate and work hard, you are going to be amazing learning superstars.

So let's get started.

Let's start off by looking at some of the keywords, animal, plants, food chain, role, research.

Do you know what any of the words mean? Can you use them in a sentence? Have a think.

This lesson is split into three parts.

The first part is called 'why are food chains important?' The second part is 'roles in a food chain'.

And the third part is 'what is research?' Let's start with the first part now.

Why are food chains important? All animals need food to stay alive, but they don't all eat the same thing, do they? What do these animals eat? We've got a picture of an iguana and you can see what it's got in its mouth.

And a picture of a robin and you can see what it's got in its mouth.

They're not eating the same thing are they? What are they eating? Have a think.

Food chains show us how animals depend on plants and other animals to stay alive.

This food chain starts with leaves on a tree and we've got an arrow going to a giraffe and another arrow going to a lion.

And we've learned that the arrows mean our food for.

So this food chain says the leaves are food for the giraffe and the giraffe is food for the lion.

A leaf is part of a plant and leaves might also be the start of some food chains.

But what animals eat leaves? They don't all eat leaves, do they? Can you think of an animal that might eat a leaf? Well, in this picture we've got a lady bird eating a leaf, and this could be the start of a food chain.

The leaf is food for the lady bird.

But I wonder if you know, can you think of anything that might eat a lady bird? How could we make this food chain longer? Have a think.

The lady bird is food for another animal and a food chain shows us the order in which this happens.

So in this food chain we've got the leaf, which is food for the lady bird, which is food for? Did you think of an animal that could eat a lady bird? Well you might have said a spider.

A spider eats a lady bird.

So in this food chain we've got a leaf is food for the lady bird, which is the food for the spider.

Let's stop and check your understanding now.

A food chain is used to show, A, the order of living things by how big they are.

B, the order of living things by how important they are.

Or C, the order that living things depend on each other for food.

Which of those answers would complete the sentence? Stop the video and have a think.

How did you get on? Should we go through the answer now? A food chain is used to show the order that living things depend on each other for food.

Did you get it? Well done scientists.

Let's look at this food chain now.

Jun has made a food chain, but I wonder, is his food chain correct? Why? So at the moment we've got mouse is food for the weasel is food for the fox.

Do you think that food chain's correct? Can you come up with a reason why? Stop the video and have a think.

Let's go through the answer now.

Jun has made a food chain.

Is his food chain correct? Why? So we've got a mouse, which is food for the weasel, which is food for the fox.

Well you might have said something like this, "Jun is not correct.

The order of food chains start with a plant.

Jun needs to add a plant that can be food for the mouse, such as corn." Well done scientists.

Let's go on to task A now.

Complete these food chains to show which living things depend on each other for food.

Leaves is food for giraffe is food for what? Can you think of something that eats a giraffe and draw it in that box? Let's have a look at the next food chain now.

An acorn is food for something which is food for a fox.

Ah, so with this food chain, we need an animal that eats an acorn that is also eaten by a fox.

That's a bit trickier, isn't it? Stop the video now.

Have a think.

Can you draw an animal that would go in those two missing boxes so that the food chains would make sense? How did you get on? Let's have a look at the answer now.

Complete these food chains to show which living things depend on each other for food.

We started the food chain with leaves and they were food for a giraffe, but you needed to think of something that would eat the giraffe.

Did you come up with something? Well you might have put a lion in there.

And Andeep says, "Giraffes are food for lots of animals.

Did you choose a different animal to complete the food chain?" I wonder if you could think of another animal that eats a giraffe.

Let's look at the second food chain now.

Complete these food chains to show which living things depend on each other for food.

We started the food chain with an acorn and then there was a gap for an animal that eats an acorn but is also eaten by a fox.

Did you think of an animal? You might have put a squirrel.

A squirrel eats acorns and foxes eat squirrels.

Andeep says, "Acorns are food for squirrels and squirrels are food for foxes.

Did you choose a different animal to complete the food chain?" I wonder whether any of you thought of something that eats an acorn that's eaten by a fox that isn't a squirrel.

Well done scientists.

Let's go onto the second part of the lesson now.

Roles in a food chain.

Food chains are made up of plants and animals and each of them has an important role.

Here's a food chain we've seen before.

The grass is food for the rabbit and the rabbit is food for the owl.

But those plants and animals have different roles and a role is a part that the plant or animal plays in the food chain.

In this food chain, the role of the caterpillar is to be food for the blackbird.

But I wonder, can you tell me what the role of the plant is? Talk to a partner or have a think.

In this food chain, the role of the plant is to be food for the rabbit.

But I wonder what's the role of the rabbit in the food chain? Can you tell a partner or have a think.

Let's stop and check your understanding now.

True or false? The role of a plant in a food chain is to be food for an animal.

Is that true or false? Stop the video and have a think.

Should we go through the answer now? The role of a plant in a food chain is to be food for an animal.

That's true.

I wonder if we can think of why that's true.

Is it A, because all animals eat plants? Or is it B, because plants can make their own food? Plants are eaten by animals.

Stop the video again and have a think.

Well you might have thought this because plants can make their own food.

Plants are eaten by animals.

Well done scientists.

Every role in a food chain is important.

Let's have a look at this food chain.

The seaweed is food for the starfish.

And the starfish is food for the seagull.

The starfish needs the seaweed in order to stay alive, it's its food.

And the seagull needs the starfish to stay alive, it's its food.

There must be enough seaweed for the starfish to eat.

Without enough seaweed some of the starfish might die.

And there must be enough starfish for the seagulls to eat.

What do you think would happen if there weren't enough starfish? What would happen to the seagulls? Have a think or talk to a partner.

Let's look at the next question now.

Which animal is missing in this food chain? Who do you agree with and why? So here's the food chain.

We've got seeds, which is food for something, and that's food for the fox.

Sam says, "It is a squirrel because the role of squirrels in a food chain is to be food for foxes." Jun says, "It is a mouse because the role of mice in a food chain is to be food for foxes." Who do you agree with? Have a think.

Pause the video and we'll come back in a minute.

How did you get on? Let's go through the answer now.

Which animal is missing in this food chain? Who do you agree with and why? Sam says it's a squirrel because the role of squirrels in a food chain is to be food for foxes.

Jun says it is a mouse because the role of mice in a food chain is to be food for foxes.

Well, Sam and Jun are both right because squirrels and mice are both animals that can be food for a fox.

They both also eat sunflower seeds.

Did you get that? Well done scientists.

Let's look at task B now.

Sam and Jen talk about the role of plants in this food chain.

So here's the food chain.

We've got plants which are food for the mouse, which is food for the owl.

Sam says, "If there were not enough plants for the mice to eat, then the mice would die, but not the owls." Jun says, "If there were not enough plants for the mice to eat, then the mice would die and the owls would die too." Who do you agree with? Talk with a partner and give reasons for your answer.

And you've got space at the bottom of your worksheet to write an answer as well.

So stop the video now and have a think.

Who do you agree with and why? Did you get it? Let's go through some answers now.

You had to think about whether you agreed with Sam or Jun, and here's what you might have said, "Jun is correct.

Plants play an important role in this food chain.

If there aren't enough plants for the mice to eat, then less mice will survive.

This means less food for the owls, so the number of owls is also likely to fall as they won't have enough to eat." Let's go on to the final part of the lesson now.

What is research? Laura wants to create a food chain.

She starts with a plant called a lettuce.

And here's a picture of a lettuce on the board.

She knows that rabbits eat lettuces, but she doesn't know what eats rabbits.

How could she find out? What could she do? Who could she ask? Have a think or talk to a partner.

Scientists often do research to find answers to their questions.

They might look in books for information.

Or they might go on the internet to find out the information they need.

They also might ask other experts or scientists to get the right information they need.

Laura does her research by looking in her favourite book.

It tells her all about what animals eat.

She finds out that rabbits are eaten by badgers or by foxes.

And now she can make her food chain by using her research.

She has the lettuce at the start and that's eaten by the rabbit and the rabbit is eaten by the fox.

Now she's got a complete food chain.

Let's stop and check your understanding now.

What does it mean when scientists do research? A, they find more out about something.

B, they measure the temperature of something.

C, they predict what might happen.

What do you think? What does it mean when scientists do research? Stop the video now.

Talk to a partner and have a think.

Shall we go through the answer? What does it mean when scientists do research? When scientists do research, they find more out about something.

Did you get it? Well done scientists.

Which would you use to research the role of animals in food chains? A, a tape measure.

B, a torch.

Or C, the internet.

Stop the video and have a think.

What would be the best thing to find out about animals in food chains? Let's look at the answer now.

Which would you use to research the role of animals in food chains? Well I don't think a tape measurer would be very good and the torch might not be very helpful either.

But going on the internet using an iPad or a tablet, that might be really useful.

Did you get it? Well done scientists.

Let's go on to task C now.

Research these animals and create a food chain for each one.

Your first food chain is going to have a crab in it.

And your second food chain is going to have a barn owl in it.

You'll need to research the role of each animal.

Find out what it eats and whether it is food for another animal.

And remember we talked about how to carry out research in an earlier part of the lesson.

You could use books that you might have at home or in the library or at school.

You might be able to use the internet to do some research, but remember to have an adult help you with that.

And you might be able to ask an expert or a scientist.

Maybe you know one or maybe you know somebody that knows lots about food chains and animals.

You could ask them to help you.

Using your worksheet, I want you to draw the food chain for the crab and the food chain for the barn owl.

I'm going to stop the video now and I want you to have a go.

Good luck.

How did you get on? Should we look at some possible answers? Research these animals and create a food chain for each one.

So your first animal was a crab.

Did you find out lots about the crab, what it eats and what eats it? Let's have a look at this example.

A crab might eat seaweed.

The seaweed is food for the crab and it might get eaten by a shark.

So we've got our first food chain here.

The seaweed is food for the crab, which is food for the shark.

Andeep says, "Is your food chain the same or different to mine?" Using research you might have found something else that crabs eats or something else that eats crabs.

Well done if you did.

Let's look at the second food chain now.

Research these animals and create a food chain for each one.

So we've got a barn owl here at the top of the food chain.

You might have said a barn owl eats a vole.

And you might have said that that vole eats berries.

And here's our completed food chain.

The berries are food for the vole, which is food for the barn owl.

Andeep says, "Is your food chain the same or different to mine?" You might have done some extra research and found something else that eats barn owls or something else that barn owls eat and made a different food chain.

Well done if you did scientists.

Let's review what you've learned this lesson.

Food chains show us the order in which living things depend on each other for food.

Each plant and animal in a food chain plays an important role.

And here's an example of a food chain.

The grass is eaten by the cow and the cow is eaten by the human.

Scientists use research to find out about what animals eat in the food chain.

Now would be a great time to go back to the start of the lesson and look at those keywords again.

Do you think you can use them in a sentence?.