Welcome to the unit Biodiversity.

My name is Mr. Jarvis and I'm gonna be teaching you today.

Today's first lesson in this unit is all about interdependence within ecosystems. By the end of today's lesson, you should be able to describe ways in which organisms are interdependent within ecosystems. There are five key words to today's lesson.

They're ecosystem, interdependent, producer, cellular respiration, and decomposer.

Here are the definitions of those words coming up on the screen now.

You can always pause the video if you want a little bit of time to read through them, but don't worry because we will go through the definitions as we go through the lesson.

There are three parts to today's lesson.

They are ecosystems, when we're going to remind ourselves what an ecosystem is, and then the next two sections are all about examples of interdependence.

First of all, we're going to look at examples that relate to food and feeding, and then we're gonna look at recycling.

So if you're ready, let's start with our first section, which is all about ecosystems. So an ecosystem is made up of all of the living things in a place and the interactions that they have with each other, but also the interactions that they have with their non-living surroundings.

If we look at the meaning of the word ecosystems, eco relates to the environment and a system is a group of things that are working together.

So it's how all of the things in the environment work together, both living and non-living things.

Ecosystems can vary in size.

The largest ecosystem is the planet earth.

However, they can be much smaller.

For example, a bottle garden can also be described as an ecosystem.

The living or biotic parts of an ecosystem are made up of communities.

Now remember that a community is all the interacting populations of different organisms in a specific area.

Here's some examples.

A rainforest community, all of the plants, all of the animals within the rainforest that interact with each other.

An African grassland community.

Here we have some bushes, some giraffe, some bush buck, some ostriches, some bison and some lion.

Or a coral reef community, the interactions between the coral, plants, the fish, and all the invertebrates that live within that community.

Some examples of non-living or abiotic parts of an ecosystem include the following, the soil, the different types of soil, the different types of rocks.

Some rocks can be really hard, some rocks are really soft.

Water, how much there is, what type of water it is, whether it's sea water or fresh water.

The air and the cleanliness of the air and how much oxygen is in the air, the light, how much light there is at different times of day and in different ecosystems, the levels of light vary.

The levels of light vary from season to season.

And then the human impacts of aortic factors, the non-living factors, things like litter and how that interacts with the communities, but also pollution.

So here's a check on that first part of learning that we've done today.

Which class member is providing the best description of what an ecosystem is? Is it Andeep, who says, an ecosystem is large and contains all of the living things in an area, for example, an ocean? Is it Sophia, who says, ecosystems are the non-living things, for example, the soil, where communities live? Or is it Jacob who says an ecosystem is made up of living things interacting with each other and the non-living things in a place? I'll pause for five seconds while you think about your answer and then we'll check to see if you're right.

How did you do? Let's check who got the right answer.

So the correct answer was Jacob, an ecosystem is made up of living things interacting with each other and the non-living things in the place.

Well done if you got that.

So now we're going to do a task.

Look at the bottle garden.

We've already seen a bottle garden can be an example of a small ecosystem.

I'd like you to describe the living, that's the biotic parts, and the non-living, the abiotic parts, of this ecosystem.

So you'll need to write those down.

So that means that you're going to need to pause the video at this point, and then when you've got your answers down on paper, you can come back to the video and we can check your answers, good luck.

How did you get on? I hope you didn't find it too tricky.

You were asked to describe the living or the biotic and the non-living or the abiotic parts of this small ecosystem, a bottle garden.

So how did you do? the bottle garden ecosystem is made up of the following.

Let's start with the living or the biotic parts.

The parts consist of different species of plants that we can see growing within the ecosystem and possibly other organisms that are living in the soil or on the plants.

Well done if you've got those living things correct.

There's also some non-living or abiotic parts in this ecosystem, and they include the different types of soil and rocks in the bottle.

You can see that the soil and rocks are different.

There are different layers of soil within the bottle garden.

The amount of water or moisture in the bottle is also an abiotic factor.

The light, you can see at different parts of this bottle garden, there's different levels of light.

It's shaded at the the rear of the bottle garden and it's bright at the front.

That's gonna have an impact on the ecosystem.

And the air in the bottle garden is also an abiotic part of this ecosystem.

Well done if you've got those right.

We're now gonna move on to our second part of the lesson where we're gonna start looking at examples of interdependence.

And first of all, we're going to look at examples relating to food and feeding.

So if you're ready, let's move on.

All living organisms within an ecosystem are interdependent.

You can see there are nine different organisms on the screen at the moment, and all of them link in some way or other to each other.

This means that they depend on each other for the things that they need to survive.

And one of the things that they need is to feed.

So needing food is one example of this interdependence.

All organisms need food to survive.

And all of the food that organisms eat is made by producers.

Producers make their own food.

They make their own food using water and carbon dioxide from their surroundings.

That process requires light, it's called photosynthesis.

Food chain diagrams show how food is passed from one organism to another, and food chains and food webs always begin with a producer.

So here's an example of a food chain.

Grass is food for a snail, snail is food for a thrush, and thrush is food for a buzzard.

The grass is the producer.

It makes the food for the rest of the food chain, and the snail, the thrush and the buzzard are all consumers.

All organisms need food to provide energy to carry out life processes.

And cellular respiration is the chemical process that takes place within cells that helps to provide that energy.

Food and oxygen is made into water and carbon dioxide and the energy that's produced during that chemical process is used by organisms to carry out life processes such as growth, movement and reproduction.

There are seven life processes that living things carry out.

Can you remember them? I'll give you a few seconds to think.

Maybe you've thought of some of them, here's a clue.

I'm going to pause for five seconds and then we're gonna come back to see how many of the seven you've remembered.

So how many have you got do you think? Let's check them.

The seven life processes that living things carry out are movement, respiration, sensitivity, that's responding to the environment, growth, reproduction, excretion, getting rid of waste, and nutrition.

Without food, living organisms will not be able to carry out these life processes, and that means that without food organisms will die.

We've already seen that cellular respiration happens in all living organisms and that it takes place within cells.

And we've also seen that food and oxygen is made into water and carbon dioxide during the process of cellular respiration.

But let's look at those different chemicals, the food and the oxygen and the water and the carbon dioxide, and see how they get into the process of cellular respiration.

Well, the food, producers make their own food.

Consumers get food by either eating producers or by eating other consumers.

But remember, in a food chain, all of the organisms within the food chain rely on the producer for food.

The oxygen is taken in from the air or water within an organism's surroundings, and producers release oxygen into their surroundings when they make their own food by that process that I called photosynthesis.

In terms of the water, water is released into an organism's surroundings, and producers take that in and use it during photosynthesis to make their own food.

Carbon dioxide is released and that's released into the air or the water that the organism's surroundings.

Producers take in this carbon dioxide and make it into their own food, again via that process of photosynthesis.

As organisms make or eat food, they grow.

We can see some different organisms in the pictures on this slide.

We have an adult and a baby elephant.

As the baby elephant eats more, it's going to grow into an adult.

And we've also got different sized cacti growing in the desert.

Consumers also excrete waste from the food that they eat.

Here's an example of that, some cow dung in a field.

And eventually all organisms will die.

Dead organisms and the waste of organisms are actually a source of food for some organisms. And those organisms are called decomposers.

Decomposers are organisms that feed on the remains of other living organisms. Here's a check.

I'd like you to match the descriptions with the words on the screen.

So the descriptions we have are an organism that eats other organisms for food, this is needed to provide energy for life processes, the process that provides energy from food, an organism that can make its own food, and these feed on the remains of other living organisms. They're the descriptions.

We've then got the words food, consumer, producer, respiration and decomposer.

You'll need to pause the video while you just match those descriptions with the words.

And then when you're ready, press play and we'll check to see whether you got them right.

So here are the answers.

An organism that eats other organisms for food is a consumer.

This is needed to provide energy for life processes, it's food.

The process that provides energy from food is respiration.

An organism that can make its own food is called a producer.

And these feed on the remains of other living organisms, they're decomposers.

Well done if you've got them all right.

Here's now a practise task.

Lucas has written some notes about why food is important, but he's made some mistakes.

Each line of his notes contains one mistake.

Can you identify the mistakes and help him by rewriting his notes? So here is what Lucas has written.

He said that some living organisms need food.

All organisms rely on consumers for food.

Excretion is the life process that uses food to provide energy.

This is a physical process.

The energy is used for other life processes such as growth, reproduction and walking.

And organisms that feed on dead organisms or waste materials are called producers.

You'll need to pause the video, rewrite Lucas's notes, and then when you're ready, press play and we'll see whether you corrected them well, good luck.

How did you get on? Well, let's check to see whether you managed to correct Lucas's mistakes.

Remember, each line contained one mistake, let's see.

So first of all, it's all living organisms need food.

All organisms rely on producers for food.

Remember, producers make their own food.

And respiration is the life process that uses food to provide energy.

That's a chemical process.

And that energy is used for other life processes such as growth, reproduction and movement.

And finally, organisms that feed on dead organisms or waste materials are called decomposers.

Well done if you've got all six of those answers correct.

That brings us to the third part of the lesson.

We're gonna look at some more examples of interdependence and we're gonna focus on recycling.

So in particular, we're gonna be looking at those decomposers.

So if you're ready, let's move on.

We've seen that all organisms eventually die.

Plants and the bodies of animals are food for some organisms, and there are a variety of organisms that feed on dead animals.

The animals that feed on other dead animals are called scavengers.

They go around, they find dead organisms and they eat them.

We've got two examples here, some vultures feeding on a dead giraffe and some hyenas that go around picking up scraps of meat from kills, mainly from things like lions.

After scavengers have eaten most of the bodies of other animals, anything that's left over is eaten and broken down by decomposers.

And decomposers are organisms that feed on the remains of living organisms. Some examples of decomposers include fungi, mushrooms, toadstools, but also moulds, bacteria and invertebrates such as insects, worms, woodlice and millipedes.

Decomposers are essential for all living things, and that's because they're essential in helping to return essential chemicals that are used by producers.

Just think what would happen to the essential chemicals in bodies of dead organisms if there were no decomposers? Think about it for a moment.

Well, if there were no decomposers, then nothing would get broken down, and anything that died would just stay on the surface of the habitat.

So over time, dead organisms, dead bodies would build up and build up and build up.

But more importantly, if those essential chemicals are not returned to the soil, then plants and producers wouldn't be able to grow in a healthy way because they need some of those essential chemicals, for example, nitrates to help them to grow and help them to remain healthy.

So which of the following is not a decomposer? Is it a field mushroom, a hedgehog, an earthworm or soil bacteria? I'll give you five seconds.

The correct answer is hedgehogs.

Well done if you've got that.

Decomposers also recycle dead producers and some of the parts of the producer that are lost, for example, leaves and fruits.

Here are three pictures.

We've got a tree that's dead, and you can see that decomposers have started to eat the inside of that tree and break it down.

We've got some windfall apples in the middle picture.

Those apples have been lost by the tree and they're being broken down by decomposers.

And the chemicals that are essential are in the soil for plants to grow are being returned.

And the final picture is a common one in this country in the autumn, where some of the trees lose their leaves.

Those leaves get broken down by decomposers and any of the chemicals that are essential, that are needed by producers in the soil are returned.

Some organisms also make use of other organisms' waste.

For example, dung beetles are insects that feed on dung.

And we've got a picture here of two dung beetles rolling a ball of dung along the ground.

The dung beetles will eventually bury this dung, and that helps other organisms that are within the soil to decompose it, that returns the nutrients to the soil for producers to use.

Decomposers are part of the food chain.

All organisms are eventually eaten by decomposers.

So here's some grass, it's eaten by an elephant and the elephant is eaten by bacteria.

So we've got a small organism with the grass, a huge organism with the elephant that's eating it, and then a really tiny organism in the bacteria that breaks down the elephant.

Why are decomposers such an important part of the ecosystem? Is it A, they produce their own food to help them survive, they break down dead organisms and return chemicals to the soil for producers to use, or they break down dead organisms and provide food for consumers? I'll pause for five seconds and then we'll check your answer.

The answer is B.

Decomposers are important in an ecosystem because they break down dead organisms and return chemicals to the soil for the producers to use.

Well done if you got that right.

Let's move on to our final practise task today.

Jacob is confused.

His teacher has told him that a cow has died and been broken down by decomposers.

And the skeleton in the picture is all that remains at the moment of this dead cow.

Jacob says, "I know "that producers always start a food chain diagram, "but the decomposers are eating an animal.

"Surely this food chain begins with a consumer." I'd like you to explain to Jacob how he's wrong and draw a food chain diagram which includes the decomposer.

You'll need to pause the video, write down your answer, and then when you're ready, press play and we'll check to see how well you've done, good luck.

So let's start with the food chain diagram.

The food chain diagram for this food chain is grass is food for the cow is food for the decomposer.

So grass, cow, decomposer.

So why is Jacob wrong? Well, the food chain still begins with a producer.

The producer makes the food, it passes that food onto the cow, and the cow is then food for the decomposer.

So the cow got its food from the grass, and the decomposer is also a consumer because it feeds on another consumer, the dead cow.

The decomposer is returning some of the chemicals in the body of the cow back to the soil for other producers to use.

Well done if you got that right answer.

So that brings us to the summary of the lesson today and what we've covered.

We've seen that ecosystems are made up of communities of organisms that interact with each other and the non-living parts of the environment.

We've seen that all organisms within an ecosystem are interdependent because they depend on each other for the things that they need to survive.

We know that all organisms need food to survive, and that all of the food is made by producers.

Food is used in cellular respiration to provide the energy that organisms need for other life processes.

And finally, we've seen that when whole parts of organisms die, a number of organisms use this material as food.

The organisms that live on the remains of other organisms are called decomposers, and the decomposers help to return nutrients back to the soil for producers to use.

Thanks for learning with me today.

It's been great teaching you and I'm looking forward to seeing you again in the future.

Bye for now.