Albert Teen
powered by
Albert logo

YOU ARE LEARNING:

pointer
Food Chains
lessonMenuButton

Food Chains

lesson introduction

Food Chains

Food chains show the transfer of energy, which happens when one organism becomes food for another. All food chains begin with organisms that photosynthesise.

All energy from life on Earth originates from just one enormous source. Which one?

hint button

So there are organisms on Earth that can take sunlight and essentially turn it into food. Which organisms are those?

hint button

So plants can turn sunlight into food or energy stores. What do we call that process?

hint button
1

To recap! All energy on Earth originates from the Sun

Without the Sun there would be no energy (no food) on Earth!

block image
2

Plants take sunlight and turn it into energy (food)

We call that photosynthesis.

block image
3

Photosynthesis

Plants take sunlight, carbon dioxide and water and turn it into oxygen and glucose.

block image
4

Plants use the glucose to grow

When plants grow, that produces more biomass. That means there is more energy (food) for plant eaters to consume.

block image

So when plants grow, that produces more biomass. What do you think biomass really means?

hint button
1

This is a food chain

It shows how biomass is transferred from one level of the food chain to the next.

block image
2

Plants can produce biomass via photosynthesis. What are plants called in a food chain?

hint button
block image
3

Now, rabbits consume plants, for example grass. What are they called in this food chain?

hint button
block image
4

Foxes eat other animals that have already taken their food from plants. What are foxes called in a food chain?

hint button
block image
5

The next level would be called the tertiary consumers

Most food chains only have up to tertiary consumers, because the amount of biomass reduces for every level. For example, there is a lot less rabbit mass for foxes to eat than there is grass mass for rabbits to eat.

block image

What do we also call secondary consumers, for example foxes?

hint button

What do we also call primary consumers, for example rabbits?

hint button
1

This rabbit weighs 1,000 g1,000 \space g. After it has eaten 1,000 g1,000 \space g of grass, it weighs 1,100 g1,100 \space g. How much of the grass' biomass got transferred to the rabbit? Give your answer as a percentage.

hint button
block image
2

This fox weighs 5,000 g5,000 \space g. After it has eaten the rabbit, it weighs 5,110 g5, 110 \space g. How much of the rabbit's biomass got transferred to the fox? Give your answer as a percentage.

hint button
block image
3

So for every level up in the food chain, only about 10%10\% of biomass gets transferred. How much does that mean is lost from the food chain in %\% between every step?

hint button
block image
1

This graph shows the population of foxes and rabbits over time

The populations fluctuate in relation to each other.

block image
2

If there are few foxes, there are _________ rabbits.

A) also few B) lots of

hint button
block image
3

When the fox population is high and the rabbit population is low, the fox population starts to ___________.

A) go down B) go up

hint button
block image
4

When the rabbit population is lower, there is less food for the foxes, so the fox population ____________.

A) decreases B) increases

hint button
block image
5

On the other hand, when the fox population is down, the rabbit population has fewer predators, so it can __________.

A) decrease B) increase

hint button
block image
6

When the rabbit population increases that can again support more foxes

And so these two populations continue to balance each other out.

block image
1

Summary! There are different levels in a food chain

Each level in the food chain lives off the level before it.

block image
2

The first level are the producers

They are plants that can produce biomass form sunlight.

block image
3

The second level are the primary consumers

They eat plants.

block image
4

The third level are the secondary consumers

They are predators that eat primary consumers (their prey).

block image
5

The fourth level is the tertiary consumers

Food chains don't normally have levels beyond tertiary consumers, because the amount of biomass that gets transferred from level to level very quickly reduces!

block image
6

Only about 10%10\% of biomass gets transferred from level to level in a food chain

That means that around 90%90\% of biomass disappears out of the food chain.

block image