Lesson video

Hello everyone.

How are you today?

I hope you're feeling really good.

My name is Ms. Av-sal and I'll be your teacher for this lesson.

I'm feeling very happy about that because we've got such an interesting topic today.

We are looking at, guess what?

The human skull.

I wonder how much you've ever thought about human skulls.

Hello tap.

You've got one right here.

Our lesson is called human skulls using evidence from the past and it comes from the unit of work evolution and inheritance.

So, if you are ready to dive into the topic of the human skull, if you have some energy, focus and enthusiasm, then we'll begin our lesson now.

The outcome for today's lesson is, I can describe how human skulls have changed over time and use fossil evidence to suggest reasons why.

I hope this sounds interesting to you.

We have some keywords in our lesson and I'd like to go through them one at a time saying them out loud.

My turn.

Your turn.

Are you ready?

Prehistoric.

Fossil.

Evidence.

Ancestor.

And skull.

It's good to hear these keywords out loud.

And now turn to someone nearby and tell them, have you heard of any of these keywords before?

And do you know what they mean?

Thanks for sharing.

Let's find out the definitions for these keywords.

Prehistoric times are time periods which came before written records began.

A fossil is the remains or imprint of living things that are sometimes preserved in rock.

Evidence is information which helps us to prove that something is true or not true.

Your ancestor lived in the past and is directly related to you.

The skull is the name for the bones of the head.

These are our keywords, prehistoric, fossil, evidence, ancestor, and skull.

Let's be on a lookout for them.

Let's listen out for them.

Let's think carefully about these keywords.

They'll be coming up in today's lesson.

Our lesson today is called human skulls using evidence from the past and it has two learning cycles, finding out about the past and changes to skulls over time.

Let's begin by finding out about the past.

Scientists estimate that modern humans have been living on earth for around 200,000 years.

The first written records were made by humans around 5,000 years ago by the ancient Egyptians, and here we can see some ancient Egyptian hieroglyphics.

So fascinating.

We call the time before this prehistoric because it is before we had a written record of history.

With no written records, how can scientists find out about prehistoric humans?

Pause here and share with someone, what do you think?

Thanks for sharing.

Let's hear from Aisha and Alex.

I think they could use fossils, but I think fossils are only dinosaurs and other extinct animals.

What do you think about this question of fossils?

Thanks for sharing.

Scientists who study prehistoric humans depend on evidence from fossils.

And here we can see a fossilized human skeleton.

Thousands of fossilized bones and teeth from humans have been unearthed by scientists, giving us lots of evidence about our ancestors.

Let's have a check for understanding.

What is the best source of evidence we have for learning about prehistoric humans?

Choose from these options.

A, writing done by prehistoric humans.

B, human skeleton fossils.

C, photographs of prehistoric humans.

Pause here while you decide what's the best source of evidence we have for learning about prehistoric humans.

Well done if you selected answer B.

Indeed, human skeleton fossils are the best source of evidence we have for learning about prehistoric humans.

What clues could we gather from this fossilized skeleton that tell us about the human when it was alive?

Pause here and share with someone.

What are those clues?

Thanks for sharing.

Skeletons are a frame of bones for support, protection, and movement.

We can gather clues as evidence about all of these things by looking at a skeleton.

We can get a good idea of what shape and size an animal would've been by looking at its skeleton.

Here we can see the human skeleton and body shape.

Skeletons protect our major organs.

Scientists have observed that older human skeletons have larger rib cages.

They've used this as evidence to suggest that prehistoric humans had larger lungs.

Why do you think this might have been?

Pause here and share with someone.

Why might prehistoric humans have had larger lungs?

Thanks for sharing your ideas.

Some scientists think that prehistoric human ancestors had larger lungs because they needed more oxygen to fuel their taller, stockier bodies.

Skeletons help animals to move.

Can you find clues as evidence for how each of these animals moved by observing their skeletons?

Pause here while you do this.

Thanks for having a go at that.

Let's hear some responses.

Here's Jun.

I can see this animal has four jointed legs.

I think it moved on land and could run quite fast like a horse or deer.

Here's Sofia.

It looks like this animal had fins, so I think it could swim.

I can't see legs, so I don't think it could walk.

I wonder if you had ideas similar to these.

Let's have a check for understanding.

Use the evidence from the fossil to suggest how this animal might have moved.

Select from these options.

A, it moved mostly through water.

B, it mostly walked on two legs.

C, it mostly walked on four legs.

D, it mostly flew through the air.

So pause here while you take a good look at this fossilized animal skeleton, and then select how this animal might have moved from the options given.

Well done if you selected option A.

Indeed, the evidence from this fossil suggests that it mostly swam through the water with its fins that we can see there.

We can also use fossilized teeth to tell us about what the animal's diet may have been like.

What kind of foods you think these animals ate?

Pause here while you take a look at their teeth and decide what kind of foods you think they ate.

Thanks for sharing.

Let's hear some responses.

Here's Sam.

This animal doesn't have any sharp canines at the front of its mouth, so I don't think it caught prey.

I think it used its teeth at the sides to grind down plants.

And here's Alex.

This animal has lots of sharp teeth.

I think it was a carnivore who used its teeth to catch and tear apart prey.

Wonder if you had ideas similar to these.

We can even gather evidence to suggest how the animal caught or found its food.

Here's Andeep.

This skeleton has long legs, short front legs, and a big jaw with lots of sharp teeth.

I think it ran after its prey and caught it in its mouth.

I wonder if you'd agree, and also I wonder if you've ever seen a fossilized skeleton like this before?

And here's another fossilized skeleton.

How do you think this animal found or caught its food?

Pause here and share with someone.

Thanks for sharing.

Let's hear from Laura.

This animal has a tail and no arms or legs.

I think it swam through water and found food.

I wonder if you had an answer like this.

Let's have a check for understanding, true or false.

The only thing we can learn from a fossilized skeleton is the shape of the animal.

Pause here while you decide, is this statement true or false?

Well done if you selected false.

And now I'd like you to justify your answer by selecting from one of these statements.

A, we can't learn what shape it was because it doesn't have any soft body parts left.

Or B, we can gather lots more evidence such as how it moved and what it ate.

Pause here while you choose from one of these statements to justify your answer.

Well done if you selected statement B.

Indeed, we can gather lots more evidence such as how it moved and what it ate.

And now it's time for your first task.

I would like you to explain how we could use a human skeleton fossil to answer the questions.

One, what shape was the human?

Two, what was it's height?

Three, how did it move?

Four, how did it get its food?

And five, what did it eat?

So pause here while you explain how we could use a human skeleton fossil to answer these questions.

I'll see you when you're finished.

It's good to be back with you.

So how did you get on with explaining how we could use a human skeleton fossil to answer these questions?

Here's question one.

What shape was the human?

Perhaps you said, we could arrange the bones and use their shape to give us an idea of the overall shape of the human.

Great answer.

Number two, what was its height?

We could measure the bones and estimate the height.

Three, how did it move?

We could look at the shape of its body and the type of limbs it had.

Number four, how did it get its food?

We could look at its limbs, how it moved and what its teeth were like.

And five, what did it eat?

We could look at the teeth and shape of its jaw.

Well done if you came up with explanations like these, and now we're onto our next learning cycle.

Changes to skulls over time.

Scientists can use fossils from different time periods to see how living things changed over time.

They use evidence from fossils to make theories about prehistoric humans.

Do you think humans have changed over time or have we always been the same?

Pause here and share with someone what you think.

Thanks for sharing.

Evidence from the skeletons of modern humans.

And our ancestors shows that we have changed over millions of years.

Scientists have observed changes in the skull shape of humans over millions of years.

Here are some drawings of fossilized skulls.

Pause here while you take a good look at these, and tell someone nearby any differences that you notice between them.

Thanks for sharing.

So on the left we have a fossil skull that's around 3.

5 million years old.

Oh my.

In the middle we have a fossil skull that's around 1 million years old, and on the right we have a modern human skull.

Do you have any theories about why they are different?

Pause here and share with someone your theories.

Thanks for sharing your theories.

Let's have a check for understanding.

Which of these statements about human skulls is correct.

Choose from the following.

A, human skulls have changed shape over a very long time.

B, human skulls have changed shape over a short time.

C, human skulls have always been the same shape.

Pause here while you decide which of these statements about human skulls is correct.

Well done if you selected statement A.

Indeed, human skulls have changed shape over a very long time.

The round part at the back of the skull looks quite different across the different fossils.

Do you have any idea?

Do you have any ideas why this might be?

Pause here and share with someone.

Thanks for sharing your ideas.

The first skull is from a species called a Australopithecus, which lived around 3.

5 million years ago, and we can see a drawing of the Australopithecus skull.

Scientists believe it is an ancestor of modern humans.

It only had space for a brain a third of the size of ours today.

The second skull is from a species called Homo erectus, which lived around 1 million years ago, and was another ancestor of modern humans.

It looked larger on the outside, but had a similarly sized space for a brain to the modern human skull on the inside.

The shape of the jaw is also different for each fossil.

Do you have any theories about why this is?

Pause here and share with someone.

Thanks for sharing.

Scientists think that a human jaw has become smaller due to changes in our diet.

In modern times, human eat softer, more processed foods so our jaws don't need to be as long and strong to rip and tear food.

Do you notice any other changes in the human skulls over time?

Pause here and share with someone.

Thanks for sharing.

Let's hear some responses.

Here's Jun.

I noticed the face looks flatter in the most recent skull.

And Sam, I noticed the teeth are wider in the older skulls.

I wonder if you notice these changes as well.

Let's have a check for understanding.

Which of these statements is incorrect?

Choose from the following.

A, human skulls have changed shape over time.

B, human brains have changed in size over time.

C, human teeth have become smaller over time.

D, human jawbones have become larger over time.

Pause here while you decide which of these statements is incorrect.

Well done if you selected statement D, this statement is incorrect, and statements A, B, and C are all correct.

Let's have another check for understanding.

Why do scientists think human jawbones may have become smaller over time?

Choose from these options.

A, because modern humans eat tougher, more chewy food.

B, because modern humans eat more processed foods that are soft.

C, because modern humans brush their teeth.

Pause here while you decide.

Well done if you went for option B.

Indeed, scientists think human jawbones may have become smaller over time because modern humans eat more processed foods that are soft.

And now it's time for your next task.

First of all, I'd like you to closely observe the three skulls from different time periods and explain the differences you can see.

So we've got skull A, which is around 3.

5 million years old.

Skull B, which is around 1 million years old, and skull C, a modern human skull.

So pause here while you have a go at this task of closely observing the three skulls and explaining the differences you can see.

I'll see you when you're finished.

That's good to be back with you.

How did you get on with that task of closely observing the three skulls from different time periods and explaining the differences you can see?

Perhaps, you said something like this.

I noticed that the older skulls had larger and longer jaws, which became smaller over time.

The teeth were also wider on the older skulls and they looked like they stuck out a bit more than they do now.

I noticed the round part at the back of the skull was much smaller on skull A than it was on the other two.

The eye sockets looked a little larger on skull B than they did on the others.

I noticed a large brow ridge over the eyes on skull A, but wasn't there on the other two.

Great observations.

And for the next part of your task, I'd like you to choose one of the differences you observed and suggest a theory for why this change might have happened.

Pause here while you share your theory.

It's good to be back with you.

How did you get on with choosing one of the differences you observed and suggesting a theory for why this change might have happened?

Let's hear from Lucas.

I noticed that the eye sockets are smaller on the modern skull C than they were on the older skull B.

I think this might be because modern humans do not have to look out for predators like prehistoric humans have to.

It might also have been to allow more light to enter their eyes in the dark since they wouldn't have had easy access to light at nighttime like we do now.

Great theory, Lucas.

And I wonder if your theory is similar to Lucas's?

Pause here while you compare your theories.

Thanks for doing that and for joining in with this lesson.

In our lesson, human skulls using evidence from the past we've covered the following.

Scientists use fossil evidence to help them learn about how our ancestors have changed over time.

Human skulls from different time periods show changes in characteristics such as skull, shape, brain and jaw size.

Modern day skulls show differences suggested by scientists linked to humans chewing softer, processed food.

Well done everyone for taking part in this lesson.

It was great to explore human skulls with you to dive into the fossilized evidence to find out about changes over time.

It was so interesting to compare human skulls, see what the similarities were, and crucially the differences.

I hope you enjoyed exploring this topic and sharing some of your theories as well.

I really enjoyed teaching you and I hope you enjoyed this lesson too.

I look forward to seeing you at another lesson soon.

Until then, stay curious.