1. Science - Year 3/4B Summer 1
Animals including humans
The Circle of Life
Session 1
Teaching PowerPoint
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2. The Circle of Life

3. Wherever you look on Planet Earth there is life
From the highest mountains
to the depths of the oceans.
Wherever you look on Planet Earth there is life
From the wettest forests and jungles
to the driest deserts.
And every living thing depends on other living things for its survival

4. Seaweed is a type of algae that makes its own food like plants, but it also needs seawater rich in nutrients
Here’s an example
The seaweed is eaten by a shellfish called a limpet
The limpet is eaten by a dog whelk
And so the cycle continues
The dog whelk is eaten by a crab
All the creatures make waste (poo) which provides nutrients for the seawater
The crab is eaten by the seagull

5. Energy transfers from one living thing to another in the form of food.

6. We will learn all about this amazing cycle of nature and tell the story to others in a creative way – gradually putting together a wonderful, inspiring presentation.
You could use dance, drama, puppets or masks,
together with narration,
to tell your audience this incredible scientific Circle of Life!

7. To begin the story, we will find out what happens when we eat our food
Why do we need food?
To give us energy
Share ideas and make a list of everything you can think of
To keep us healthy
So we can grow
Here are some reasons you may have thought of
To repair and renew the cells of our bodies

8. Your mouth is where it all begins
Your mouth is where it all begins. Your teeth break up the food into small pieces and your mouth adds juice called saliva. The tongue moves the food around your mouth.
When animals eat, their bodies need to break down the food so it can be used. This process is called digestion
When you swallow the food, it travels down the food pipe (the oesophagus)
There are lots of different organs inside you that help to break down food and absorb the goodness from it that you need. Together these organs are called The Digestive System
The tube opens up to form a stretchy bag called the stomach. Here the food is churned up with some acid that the stomach makes. This breaks down the food into a thick liquid
After the stomach, the food enters the intestines. First a very long wiggly tube called the small intestine. Here the body absorbs the nutrients from your food. Then it enters a shorter wider tube called the large intestine where water is absorbed
The digestive system is a long tube that begins at the mouth and finishes at the bottom.
The tube changes along the way as each part of it has a different job to do. Each part is called an organ. Let’s find out more about them
After your body has absorbed all the nutrients and water it needs, the rest is waste (we often call it poo). The scientific word for poo is faeces.

9. How does food move along the digestive system?
Lots of animals like this rabbit, have digestive tubes that run horizontally, and sometimes even up hill! So how does the food keep moving along?
Challenge
Put a small fruit (some food) in one leg of a pair of tights (a tube of the digestive system). Work with one or two friends to discover how you can move the fruit all the way to the toe end without using gravity; in other words, without raising either end of the tube!
Extra Challenge: Now work as a team to try moving the food up hill. Start with the fruit in the toe on the table. Hold the other end of the tube vertically above it. Try to move the fruit to the top of the tights.
How did you do it? Try to describe why it worked

10. Food is squeezed along the tubes of the digestive system by rings of muscle that contract.
Here a ring of muscle in the tube is contracting to squeeze the food along.
Peristalsis means you can swallow food even if you are standing on your head!
Then the next ring of muscle contracts to push it on even further
This continues with rings of muscle all the way along. It is called Peristalsis.