How do animals grow?
MADDIE MOATE: This is Fluffy. She’s five weeks old.
CHILD: Aw, she’s cute. She’s so small!
MADDIE: Fluffy is growing up fast. Like all animals, she will go through many changes as she develops and grows.
CHILD: What kind of changes?
MADDIE: Great question! Let’s have a closer look. Puppies like this one are mammals. Like most mammals, puppies grow inside their mummies before they are born. And when they’re born, they are very small and rely on their mummies’ milk for food. As they get bigger, they learn to do new things like go exploring - and they start to eat solid food. They keep on developing until they are fully-grown dogs. And then they can have puppies of their own. We call this process of birth, growing up and then new birth a ‘life cycle’.
CHILD: Do all animals have the same life cycle?
MADDIE: Hmm, I wonder? Let’s ask our expert!
YUSSEF: Hi, I’m Yussef. I’m an animal expert, and this is Cookie. He’s a crested gecko, and he’s going to help us to understand how animals grow. Lizards have a bit of a different life cycle to us mammals. Instead of the babies growing inside their mothers, most lizards lay eggs. Cookie’s mum laid two eggs, which she buried in soil to keep them nice and warm, and after about two months it was time for those eggs to hatch. They have a little egg tooth that they use to break out of the eggs, and eventually when the babies grow up, they have eggs of their own and the cycle continues.
MADDIE: All chickens start their life as one of these. It’s a chicken egg. The egg provides everything the chick needs to grow inside it, and the mother - called a hen - will sit on the egg to keep it warm for about twenty-one days. When the chick is ready it will peck and kick its way out of the egg. It has small, soft, fluffy baby feathers. The chick is fed by its mother until it grows big enough to find its own food. Then it’s able to lay its own eggs and the life cycle starts again. Depending on the type of animal, a baby may look like their parent… Or look very different! This is a caterpillar. Caterpillars are baby butterflies.
CHILD: So how does this…
CHILD: …turn into this?
MADDIE: Well, butterflies have a different kind of life cycle. Some butterflies lay lots of eggs at once. But many others - like this one, called a Speckled Wood butterfly - lay one egg at a time. Normally somewhere that her baby can eat as soon as it hatches, like on a leaf. The egg hatches as a caterpillar. And now it has to eat… and eat… and eat! Eventually it stops eating and becomes still and it forms a protective layer like a shell around it. At this stage the caterpillar has become something called a pupa. It might look like not much is happening from the outside, but inside there are all sorts of changes taking place. And when it finally comes out again it’s completely different. The caterpillar has become a butterfly! Now it’s ready to lay its own eggs and the life cycle starts again.
These are tadpoles. They have to go through a big change to become frogs. Let’s have a closer look at the life cycle of a frog…
A mother frog lays her eggs in water. When they’re ready the tadpoles break their way out of the eggs and hatch into the water, where they swim, breathe with gills and eat plants. As it grows, the tadpole develops a strong tail. Then back legs grow and lungs. The tadpole grows front legs and then it can leap out of the water. Now it eats insects and its tail disappears. It takes two to four years for it to become a fully-grown adult, and then the life cycle can begin again. What are you lot up to?
CHILD: We’re drawing pictures…
CHILD: …of what we’re going to look like…
CHILD: …whenever we’re older.
MADDIE: Those look great! Good job! All animals are different but one thing we have in common is that we all go through changes as we grow and develop.
Video summary
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In this video we explore the life cycles of mammals, amphibians, birds, reptiles and invertebrates, including how a caterpillar changes into a butterfly and a tadpole into a frog.
These animals have an exciting journey as they grow from infant to adult and change as they grow.
With narration from Maddie Moate and expert advice from zoologist, Yussef Rafik, this video demonstrates the life cycle of various animals, showing they change as they develop and grow.
Teacher notes
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Discussion Points:
1. Life cycles:
- Discuss what a life cycle is and how all living things have one.
- Do all life cycles look the same? Do some living things change more than others as part of their life cycle?
- Discuss what the human life cycle looks like, how is ours different to that on the video?
2. Butterflies:
- Discuss where the life cycle of a butterfly starts?
- How does a butterfly change, grow and develop as it moves through the life cycle.
- What do pupils think is the biggest visible change as part of the life cycle of a butterfly?
3. Frogs:
- Discuss where the life cycle of a frog starts?
- How does a frog change, grow and develop as it moves through the life cycle.
- What do pupils think is the biggest visible change as part of the life cycle of a frog?
Suggested Activities:
1. Life cycles - visual:
- Provide a selection of pictures of different animals for children to view and discuss.
- Can children sort these into the animal families and give reasons for their choices?
2. Frog life cycle:
- Create a simple hanging decoration to show the phases of the life cycle of a frog.
- With the pupils, consider each phase and create a small picture, title and text to go with this, creating a cyclical display to showcase the life cycle.
3. Butterfly life cycle:
- Using a paper plate and piece of card, create a life cycle diagram of a butterfly.
- Cut a slit into the card and split pin this over the top fo the plate to create a spinning dial to show the varying stages of a butterfly life cycle.
4. Younger to older or older to younger:
- Provide photographs to show either a younger or older animal, can pupils draw what they think the opposite would look like.
- For example, if a photograph of a butterfly, pupils would draw a picture of a caterpillar to show the younger stage of the animal.
Curriculum notes:
- This video aligns with Science in the National Curriculum in England, Northern Ireland, and 1st Level in Scotland. It also supports the Science and Technology Area of Learning and Experience within the Curriculum for Wales.
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