Hi everyone.

I'm so pleased you've come to learn some science with me today.

I'm Mrs. Horan and I'm really looking forward to learning all about a really interesting aspect of animal lifecycles with you in today's lesson.

Today's lesson is part of the unit on reproduction and lifecycles of animals.

The lesson is called "Animal Gestation Periods" and we'll be learning all about the ways some animals grow and develop at the very beginning of their lives.

The outcome for our lesson today is to use information to predict the gestation periods of different animals.

This lesson builds on what you already know about different types of animal in their life cycles, and as part of our big learning question, how do living things grow and reproduce? These are the keywords that we're going to be focusing on today, animal, offspring, gestation period, prediction and research.

Some of those are probably completely new to you, but don't worry, we're going to have a really good look at them during the lesson.

Here are some explanations of our keywords.

As I said, all the new words will be explained when we get to them during the lesson, so you don't need to look too closely at them now.

They're just here in case you need a reminder of them later on and want to have a look back for a quick check.

Our lesson today is divided into three parts.

Let's get started with the first part.

What is gestation? Jun and Laura are talking about some young animals.

We already know that an animal is a living thing which moves and eats other animals or plants.

Laura says, some animals like birds and amphibians develop and grow inside an egg until they're ready for the outside world.

Jun says, how do mammal offspring develop before birth if they do not hatch from eggs? Remember, mammals are warm-blooded, vertebrate animals like the young chimpanzee you can see there.

Offspring are the babies that animals have.

What do you think? So we know that mammals don't lay eggs, so what do you think about what Jun has said? You might want to pause the video here to have a think or a chat with a partner.

Mammal offspring grow and develop inside their mother's bodies until they're ready to be born.

The time an animal spends growing and developing inside its mother is called a gestation period.

During a gestation period, the mother is said to be pregnant.

You can see some pregnant animals in the pictures here.

Can you see how their middles are bulging more than normal? That's because they have offspring inside them taking up space.

Gestation period is part of our key words for today.

The word gestation means growing and developing inside a mother animal and period is just the word for an amount of time, so together gestation period means an amount of time that an animal offspring spends growing and developing inside its mother.

Let's have a really quick check for understanding now.

What is the name for the time an animal's offspring spends in its mother's body? Well done, it is called a gestation period.

At the beginning of the gestation period, the animal is not fully formed and needs some time to develop into its young size and form.

When we use the word form in this context we mean shape, so at the beginning of the gestation period, the animal is not yet the shape it will be when it will be born.

It might have fewer or shorter limbs, for example, you can see in the picture there a pregnant human holding a baby scan.

These scan pictures are really amazing.

They're called ultrasound scans and doctors use sound waves to build up a picture of the offspring inside his mother.

We'll take a closer look at some of these in a moment.

The offspring grows inside an organ called a womb inside the mother's body.

Sometimes people think babies grow inside a mother's stomach, which is understandable because of where the bump is on the mother.

It does kind of look like it's around the area and we often say someone has a baby in their belly, but remember the stomach has stomach acid in for digesting food, so it definitely wouldn't be a safe place for offspring to develop.

Here we have three ultrasound pictures of the same baby growing and developing.

Can you see how this baby changes over time inside her mother's womb, we have a picture where the baby is nine weeks old, another from where she's 12 weeks old and one more where she's 20 weeks old.

Pause the video here and have a really good look at these pictures and see if you can see how the baby changes over time.

Let's have a really good look at how this baby changes then.

You can see in the first picture the body and head are around the same size.

We can't see any arms because they're too small to see at this point and you can see that her legs are very short, pretty much just little stumps.

In the second picture from three weeks later, you can see that there is more definition between the baby's head and body, with her neck looking a bit thinner in comparison, her face look a little more defined and you can just about see a little nose sticking out.

You can also see that there are little arms or hands at the side.

Her legs are longer and there are the beginnings of little feet on the end of them.

In the final picture, you can tell at the baby's quite a bit bigger now because she's starting to curl around to fit into the space inside her mother.

Her legs are much longer and you can see the knees there with her calves and feet being outta the picture.

My favourite thing about this last picture is that you can see all her vertebrae and her backbone have formed, can you see those little blobs along her back? They haven't yet formed in the from 12 weeks, isn't it amazing that doctors have the technology to see animals inside their mothers in so much detail? As well as the shape of the animal and its limbs, the internal organs also develop during a gestation period, so it's brain, stomach, lungs, and all the other important organs and systems develop during this time.

While the offspring is inside its mother, it gets all the oxygen and nutrients it needs from her.

It cannot breathe inside the womb and it has not yet developed its digestive system and enough to be able to eat, but the oxygen and nutrients it needs to grow and develop healthily are passed from the mother into the baby.

When the heart, lungs, stomach and other organs are ready for life on the outside world, the offspring is born.

It comes out of its mother able to breathe, digest milk from its mother and move its limbs.

Let's have another quick check for understanding.

What two things can you name that the offspring gets from its mother during the gestation period, we have A, milk, B, oxygen, and C nutrients.

Which of these did the offspring get while it is developing inside its mother? So the correct answers were B, oxygen and C nutrients.

The offspring doesn't get milk from its mother until after it's born.

Time to apply some of our new learning to a practise task, your job is to use the words in the box on the right to fill the gaps.

You won't need to use all of the words, so think carefully about the ones you do want to use.

The text says "The time a young animal spends inside its mother's body is called a period.

During this time, it gets everything it needs from its, including and nutrients.

When it's body and are fully formed, it is born." Pause the video here and have a go at completing the sentences.

Welcome back, let's see how you did.

The time a young animal spends inside its mother's body is called a gestation period.

During this time, it gets everything it needs from its mother including oxygen and nutrients.

When it's body and organs are fully formed, it is born.

Let's move on to the second part of our lesson now, finding patterns.

Different animals have gestation periods of different lengths.

Scientists look for patterns in the gestation periods of different animals.

This can be useful because if they know when an animal is likely to give birth, they can be ready to give it all the support both it and the new baby animal need.

They might look at the size or mass of the animals to consider if this has an effect on the length of the gestation period.

Alex has been researching animal gestation periods.

Research is another of our keywords for today and it means to find out about something or to investigate it carefully.

Here is what Alex has found out.

He has completed a table showing the mass and gestation period of three different animals.

We can see from the table that a mouse has a mass of 0.

02 kilogrammes and a gestation period of just 20 days.

A cheetah has an average mass of 55 kilogrammes and a gestation period of 95 days, and the rhinoceros has a mass of around 2,900 kilogrammes and a gestation period of 520 days.

What do you notice about this data? Can you see any patterns? You might want to pause the video here to discuss this with a partner.

Did you notice any patterns? Let's see what Alex spotted.

He looked at the data he had collected through research.

He found a pattern in the gestation periods of different animals.

He says, "I noticed that for the animals I researched, the larger the mass of the animal, the longer the gestation period." Did you notice the same thing? You think this is true for all animals, whether you do or don't, why do you think so? Take a minute here to think about your ideas and maybe tell a partner.

We know that larger animals tend to have longer gestation periods.

You'll notice that it says tend to have longer gestation periods there, not always, because it is not an exactly equal pattern for all animals with a direct link between mass and gestation time, but it does follow a pattern for most animals.

This is because larger animals have larger offspring which need longer to grow and develop.

Let's have another quick check for understanding now.

Take a look at these three statements and decide which one you think is correct.

Is it A, larger animals tend to have shorter gestation periods? Is it B, larger animals tend to have similar gestation periods to smaller animals or is it C? Larger animals tend to have longer gestation periods.

Correct Statement of these three is C.

Larger animals tend to have longer gestation periods.

Animal scientists use patterns in their results to make predictions about animal gestation periods.

You can see another of our keywords for today there a prediction.

What is a prediction? A prediction is a carefully thought out statement about what you think will happen or what will be found out from inquiry.

Scientists use information they've gathered from inquiries to help them make predictions about what they might find out from further inquiries.

So a prediction is very different from a guess.

To make a prediction, you need to think carefully about what you have already learned and what you already know.

This information helps you to make a prediction that is more likely to be accurate.

We are going to use what we have learned about patterns in animal gestation periods to help us out with some predictions.

Before we do that, let's check in on how you're doing.

Predict which of these three animals will have the shortest gestation period.

We have A, a mouse, B, a squirrel, and C, a dog to choose from.

Use what you've just learned to help you predict which of these animals will have the shortest gestation period.

Did you think it was the mouse? The mouse will have the shortest gestation period because it's the smallest of these three animals.

Now time for a task, there's a reminder about what we have learned here.

Animals with a larger mass tend to have a longer gestation period.

We have six animals and their masses here in the table.

You need to use what you already know to predict the gestation period of each animal in the table, we have a hamster with an average mass of 0.

125 kilogrammes, a fox with an average mass of six kilogrammes, a red kangaroo with an average mass of 47 kilogrammes reindeer with an average mass of 101 kilogrammes giraffe with an average mass of 800 kilogrammes and an elephant with an average mass of around 6,000 kilogrammes.

Pause the video here to make your predictions about the gestation period of each of these animals and come back when you are ready.

How did you do, did you find it easy or quite challenging to make your predictions? Here are some predictions made by Sophia using what she knows about larger animals tending to have longer gestation periods.

She thought the hamster would have a gestation period of 10 days.

The fox would have a gestation period of 60 days, 90 days for the red kangaroo and 180 days for the reindeer.

She thought the giraffe would have a gestation period of around 300 days and the elephant 500 days, were your predictions similar? It might be interesting to compare your predictions with a friend and seeing if there are any similarities.

Now for the final part of a lesson finding out about gestation periods, now that we know what they are, how can we find out about animal gestation periods? Scientists find out about animal gestation periods by observing animals over time.

Gestation takes time, so scientists need to make observations over the period of time that the animal is gestating.

We can can also find out about animal gestation periods by carrying out research using secondary sources.

Since we already know quite a lot about animal gestation periods and can learn from secondary sources that have already been made, you might be wondering why scientists continue to make observations of wild animals gestation periods.

Well, it's still important that scientists work to find out about animal reproduction and gestation periods.

Thanks to the work of conservation scientists, some endangered animals such as the giant panda are becoming less at risk of extinction.

Scientists have been able to identify problems that reduce the rate at which these animals reproduce and put measures into place to support them.

Without this help, many animals may become extinct already.

Do you think you would like to become a conservation scientist and help animals to survive and thrive? Before our final practise task of the lesson, let's have another quick check for understanding.

Which of these is not a way to find out about animal gestation periods? Is it A, taking photographs of baby animals.

B, carrying out research using secondary sources or C, observing animals over time.

The answer is A, we cannot learn about animal gestation periods by taking photographs of baby animals because they have already been through the process of gestation.

For our final practise task of the lesson, we are going to see how accurate our predictions from earlier on in the lesson were.

Carry out some research or use Jacob's research on the next few slides to find out about the gestation periods of these animals.

Then compare your findings with your predictions from task B.

I can't wait to see how accurate we were with our predictions.

Pause the video here if you're going to do your own research or keep watching to see Jacob's research on the next few slides.

Here's Jacob's research.

Let's see what he found out.

Hamsters, these popular pets have babies called pups After a gestation period of around 16 days, hamsters give birth to about eight pups at once.

Red kangaroos, these marsupials have unusual birthing cycles.

The young kangaroo only has a gestation period of around 30 days.

It's still not fully formed after this time so it crawls up into its mother's pouch to continue growing for around eight months.

Fox can be found in many places from the countryside to cities.

They're pregnant for around 50 days.

Then their offsprings spend around 100 days with their mother before leaving to live on their own.

Fox cubs are blind and deaf when they're born.

Reindeer have a gestation period of around 220 days until their offspring are born.

They usually only have one calf to type will be able to stand upon their own only an hour after being born.

Giraffes usually only have one baby at a time, thought scientists do have some evidence of twins being born.

Whether they have one or two babies on the way, A giraffe's gestation period is around 460 days.

Elephant young are called calves and they stay with their mothers for an average of 16 years.

Clocking in at 680 days, elephants have the longest gestation period of any animal.

Now we have all the information we need.

Pause the video and complete your tables.

You might need to look back through the slides to find all of the data that you need.

When you're done and your table is complete, come back and we'll see how you did.

Welcome back.

Did you enjoy comparing the facts with your predictions? Here are the numbers you should have in your table.

We'll leave the column with predictions in because yours are probably different to Sophia's and we'll just take a look at the gestation period column at the end.

So for hamsters, the gestation period is around 16 days.

For foxes, it's around 50 days.

For red kangaroos, it's 30 days.

For reindeer, the gestation period is around 220 days.

For giraffes, it is 460 days, and finally, for elephants it's 680 days.

Did your finding surprise you? I know I was surprised by the gestation period for red kangaroos because it was so short compared to its mass.

I decided to find out more about kangaroos after this research and I found out some really interesting stuff.

When the baby kangaroo was born, it's only about the size of a paperclip, but still it manages to climb its way all the way up.

Its mother's belly into her pouch where it carries on growing for another eight months.

I can't imagine what that journey must be like for a teeny, tiny kangaroo.

Kangaroos are not the only animals that don't fit the pattern of larger animals having longer gestation periods.

Some others that don't fit the pattern well are lions that have a pretty short gestation period for their size and humans whose gestation period is very long compared to their mass.

Maybe if you're interested, you could find out more about these animals just like I did about the kangaroos.

That brings us to the end of our lesson.

We've learned such a lot today.

Let's recap on the key learning points from this lesson.

Mammals spend a gestation period growing and developing inside their mothers before they're born.

Generally, larger animals have longer gestation periods as they tend to produce larger offspring.

Scientists can find out about animal gestation periods by observing them or carrying out research.

We can make predictions using patterns in our results and test these by carrying out further inquiries.

Thank you so much for joining me today to learn about animal gestation period.

I hope you found this lesson as interesting as I did and that you learned some great new facts to share with others.

See you again next time.