Lesson video

Hello, scientists and welcome to this lesson.

In this lesson, we are going to be looking at what fossils can tell us about the past.

The outcome for our lesson is to describe what fossils can tell us about things that lived in the past.

There are some key words to note before we start our lesson.

The first is evidence.

The next is fossil record.

Now it's fossil.

Next up, theory.

Finally, palaeontologist.

Don't worry if you're not too sure what some of these words mean.

The definitions are coming up on the screen for you now.

Now you can have a little read and remind yourself of some of them, but if you're not too sure, you can also pause the video here and have a read of each definition.

Restart when you're ready to continue.

The first part of this lesson is called the fossil record.

Let's dig into it.

Aisha and Sophia here are talking about dinosaurs.

I love talking about dinosaurs as well.

They are fascinating creatures.

Aisha says, "Cameras hadn't been invented when dinosaurs were alive, so how do we know that they existed?" Sophia said, "Maybe stone age people did some cave paintings of them." Hmm, I'm not sure.

What do you think? I know that cameras definitely weren't around when dinosaurs roamed the earth.

So how do we know they existed? Pause the video here and discuss, restart the video when you've done that.

So what do you think? Maybe all scientists and palaeontologists have some sort of time machine that allows 'em to go back and have a look.

Hmm, I'm sure if they did, we'd probably know about it in the newspapers.

So how do we know that dinosaurs existed? Let's move on and find out more.

Humans and dinosaurs have never been alive at the same time.

We are talking about a period in the Earth's history in which humans weren't around at all.

Dinosaurs lived on earth from around 230 million years ago to around 66 million years ago.

Sophia says, "Wow, that's around 164 million years." That is an incredibly long time, isn't it? You can see there a model of a dinosaur.

At least this is a model of a dinosaur in what we think they may have looked like.

Humans like us, on the other hand, have only existed since around 200,000 years ago.

So Aisha says, "There was a gap of over 66 million years between dinosaurs becoming extinct and humans coming into existence." Sophia then says, "Well, if humans weren't there to see them and to record them and see what they were like, how do we know about them now?" Well, that's a very good question.

We still not quite answered that original question, have we? How do we know about them now? Hmm? Pause the video and discuss.

What do you think? So what do we think? How do we know about dinosaurs now? Well, the very best evidence that we have about living things that inhabited the earth millions of years ago is the fossil record.

The fossil record is a collective name for all of the fossil evidence gathered by scientists and the relative ages of these fossils.

Scientists can look at patterns in the fossil record to understand how life on earth changed over time.

So this is a great big record of all the results and investigations that scientists have done into this time period so that anybody can go and look and find out more about what they know.

Let's pause and think, what is the best evidence we have for life on earth millions of years ago? Is it cave paintings, photographs of prehistoric animals, the fossil record or diaries of ancient humans? Pause a video and discuss.

Restart when you've done that.

The answer here is the fossil record.

Unfortunately, cave paintings certainly wouldn't have depicted dinosaurs as humans have not been around for that amount of time.

Now, not all prehistoric animals lived at the same time.

The fossil record can help us to understand which animals lived and when.

For example, the Stegosaurus and the Tyrannosaurus Rex existed further apart in time than the T-Rex and the invention of smartphones.

Wow, my goodness me.

That is an incredible piece of knowledge, isn't it? Let's represent that using some sort of timeline.

Here you can see a smartphone, which was invented around 20 years ago, and the T-Rex alive around 65 million years ago.

My goodness, that is a very long time, isn't it? Now, Stegosaurus sous was alive around 155 million years ago.

So really the amount of time between the two is very vast, isn't it? Here you can see between the phone and the T-Rex is 65 million years, and between the Stegosaurus and the T-Rex is 90 million years.

I wonder if anybody was actually sitting there counting all of that.

No, of course not.

But there are ways that scientists can date these kind of things and find out more.

So life on earth has always been very diverse.

It's not just dinosaurs that we find in the fossil record.

We also have fossils belonging to fish, mammals, insects, plants, and many other types of living things as well.

Here you can see that there's a fish fossil.

It's definitely a fish.

I can see some fins and I can see the bone structure as well.

And there you can see a plant fossil.

It's where a leaf has obviously been imprinted into a plant over millions of years.

So it can take thousands or even millions of years for these types of fossils to form.

The one thing that all fossilised living things have in common though is that they died a very, very long time ago.

So true or false, all fossils are from dinosaurs.

The answer here is false.

Not all fossils are from dinosaurs.

So can we justify our answer here? Which of these statements is correct? Pause the video and discuss.

The answer here is that many other living things existed millions of years ago and have become fossils.

There are many different types of fossils.

One such example is a trace fossil.

Trace fossils can also tell us about prehistorical organisms, and these are sometimes known as imprint fossils.

So trace fossils or imprint fossils are evidence that living things existed, but are not preserved remains of the living thing itself.

An example of trace fossils include footprints, skin imprints, and coprolites, which are fossilised poo.

Here you can see an example of a fossilised footprint, and down there as well is a coprolite.

They look like tiny little rocks, don't they? I wonder who investigated further into that to find out that they were actually poo.

Let's pause and think.

What are trace fossils? Read the statements there and discuss.

Restart the video when you've done that.

The answer here is that a trace fossil is evidence that living things existed.

They're not remains, and they're not complete fossils of living things.

They're imprints, aren't they? So scientists can use fossils in this way to propose theories about living things from the past.

Remember, it's a theory that these things were there.

We don't actually have any hard proof like photographs to prove that they were real.

So using evidence from the fossil record, scientists have been able to estimate how long life has actually existed on earth.

Evidence of microorganisms preserved in rocks is the earliest proof of life that we have.

This suggests that life first appeared on earth around 3.

5 billion years ago.

My goodness, that is an incredibly long time ago, certainly longer than the invention of smartphones and certainly longer than I've been around.

Let's pause and think again.

Scientists have found evidence that life began on earth how long ago? Pause the video, read the statements and discuss.

The answer here is 3.

5 billion years ago.

That is an incredibly long time.

So this is the first task of your lesson.

Have a little read of these statements here.

Are these statements always true, sometimes true or never true? Number one is fossils are useful to scientists because they give us evidence about prehistoric life.

Number two is fossils are dinosaurs.

Number three is fossilised living things were alive many years ago.

And number four reads, it takes around a decade for fossils to form.

So for each one of these, explain how you know, are they true, are they always true, sometimes true or never true? Best of luck with that task.

Restart the video when you've done that.

So how did you get on? We have some statements here that could be similar to something that you wrote.

The answer to number one, about fossils being useful to scientists because they give us evidence about prehistoric life says, I know this is always true because every fossil is evidence of an organism that was alive at a time before there were humans to observe it.

Number two, fossils are dinosaurs.

Now, this is sometimes true because some fossils are dinosaurs, but there are lots of other fossils of living things, including mammals, fish and plants.

And don't forget about those imprint fossils that you find of poo.

Number three, fossilised living things were alive many years ago.

I know that this is always true because it takes a very long time for fossils to form.

Number four, it takes around a decade for fossils to form.

Well we've just proved that incorrect in the previous one, haven't we? I know this is never true because it takes thousands to millions of years for a fossil to form.

So I hope you enjoyed proving some of those statements true or not true.

Let's dig a little deeper into the next part of our lesson to discover more.

The next part of our lesson is called palaeontology.

Now, scientists who study the fossil record are called palaeontologists.

Here you can see a picture of a palaeontologist on a very large piece of rock.

They seem to be measuring and seem to be brushing away part of the surface there.

Now, this is because they use clues in the fossils that they find to propose theories about living things from the past.

That means that they need to be very careful around large rocks like this and scrape away small sections rather than knocking it in half.

So let's pause and think.

What's a name for a scientist who uses fossils to learn about prehistoric life? Read each one there and discuss which one is correct.

The answer here is a palaeontologist.

A palaeontologist is a type of scientist who will use fossils to learn about prehistoric life.

Now, very often a fossil doesn't tell us the whole story.

Palaeontologists have got to use clues within the fossils to suggest ideas about what it might have been like.

Here you can see a palaeontologist and they have got some sort of skeleton system there that they're trying to put together.

Now, a palaeontologist will also consider evidence from other fossils that they know or may have discovered, and then what they know about modern living things to make up their theories.

So have a look here.

What clues can you see within this fossil here? And what does it tell us about the type of living animal that it was and what may it have been like? Pause a video here and have a discussion.

Restart when you've done that.

In the picture here, you can see a very long bone that's going from what looks like a head, all the way down to the bottom.

And at the bottom there, there's another long bone coming out, going up behind it.

There are also, it looks like two legs and two arms coming out to the top.

Now, whatever this creature is, it looks like it could have had a very long neck as well.

And then some sort of ice cream cone type of head.

Hmm, I wonder if this particular animal had a beak or maybe even those long arm things at the top there.

Maybe they're not arms and they're actually wings.

Well, let's delve into it a little bit further now.

Andeep says, "Well, I can see sharp teeth, so I think that it was a predator." Oh, looking a little bit closer there, it looks like there are some sharp teeth that skull.

The shape of the bones make it look like it had wings, so I think it could fly.

Hmm, I suppose those arms there go down to some sort of hand and there's not just two fingers there, so I wonder what it could have been.

It also has legs, so it could probably walk too.

Hmm, I definitely thought those were legs as well.

In fact, they almost look a lot like human legs, don't they? Andeep also says, "I don't think it was a bird because the skull looks like it had a long nose and not a beak." Oh, I don't know.

I disagree there.

It kind of looks like it does have a beak, doesn't it? It also had a long bony tail, which birds do not have.

So it might have been a flying mammal like a bat.

Oh, okay, that's a very good point.

Now, we're not too sure on the size of this fossil here are we? So maybe this fossil is actually very, very small, and this is a really zoomed in image of it.

It's quite hard to tell from this perspective, isn't it? So what did you notice and what theories did you have about this fossil? Pause the video here and discuss with a partner.

What did you think? Excellent discussing, everybody.

I wonder what kind of theories that you had.

And remember, the context is really important here.

We're not too sure if this is a very large type of animal or if this is a very small type of animal.

Now, a palaeontologist who is looking at this type of fossil will need to take everything into consideration, even the type of size, and then compare it to the modern animals that they know as well.

How do palaeontologists make theories about prehistoric life? Do they look for clues in photographs? Do they look for evidence in fossils? Or do they study cave paintings? The answer here is they look for evidence in fossils.

So we actually have very little evidence about what colour the dinosaurs were because their soft skin decayed really long before it could become fossilised.

Dinosaurs are often drawn with some brown, grey or green scaly skin.

But I wonder why you think this is.

Pause a video here and discuss.

Why do you think they're drawn it with this type of colour scaly skin? So wonder why you thought that.

Let's find out more.

We know that dinosaurs were reptiles.

I wonder why? Now many reptiles alive today have green or brown scaly skin.

So using this evidence, we can decide that perhaps the dinosaurs did as well.

Remember, this is all a theory, isn't it? We don't actually know there were no photographs, but we can take guesses looking at the modern day creatures alive now.

We also know that prey animals need to blend into their surroundings so they don't get eaten.

Predators also need to be able to hide in their environment so that prey doesn't see them coming and then run away.

Just like you can see this example of a camouflage reptile there.

Colours like green, brown, and grey would be the best colours for this.

And of course, it would completely depend on the type of environment that the reptile is growing up in as well.

It would be more likely to be grey if it was at the mountain side.

Maybe it would be green if it lived in the grassland, and maybe it would be brown if it lived more in the woods where the forest floor is usually very brown and muddy.

Now because new fossils are being found all the time.

Palaeontologists ideas and theories about the past are always changing and improving as they gather more evidence.

For example, for a long time it was thought that the T-Rex had scaly skin like the reptiles that we have alive today.

So you've probably seen lots of drawings or models of them that look a little bit like this.

You can see those ferocious teeth there, those tiny eyes, and then all that scaly skin running all the way down them.

However, scientists have recently uncovered fossil evidence that shows that these dinosaurs had black, grey and rust coloured feathers, meaning that they looked very different to how we thought for years.

Now, I don't know if that will make the T-Rex as ferocious or scary if it came running at you all covered up in feathers like some kind of giant chicken.

So true or false, palaeontologist theories about prehistoric life often change over time.

The answer here is true.

Their theories do change over time.

So can we justify our answer here? Read the statements and decide.

The answer here is that theories change as new fossil evidence is discovered.

It's not just because palaeontologists have better ideas.

So here is the last task for the lesson.

Observe the photograph of fossils and read the palaeontologist notes very carefully here.

You need to use all the evidence you can to write a report about what the living thing may have been like.

Now, you could try and deduce what type of animal it was? How big it was? Was it a predator or a prey? What did it eat? How did it move? Using those bullet points there, construct your evidence and answer.

So pause the video here and take some notes if you need to about each of those bullet points.

I'm going to show you the different slides and then you are going to need to use all the evidence you have to see if you can write a report about the living thing and what it may have been like.

Here's the first fossil.

The palaeontologist notes, oh, it's very thin.

It has delicate bones.

It's length from head to tip of tailbone is 25 centimetres.

You can pause the video here and have a further look.

Here's the second fossil.

Palaeontologist notes are this; it has two longer horns each around one metre long.

Pause the video here and have a think.

Fossil three is here.

There are nine footprints found near the bones.

Each are 46 centimetres long and around four metres apart from each other.

Pause the video here and construct your answer.

The final fossil here is that this is around 30 centimetres long.

The museum staff found traces of fish bones and scales embedded in this coprolite.

Pause the video here and have a think about your answer.

Excellent work, let's go through each of these fossils and see if some of your notes compare to some of these.

You had to use all the evidence that you could to write a report about each living thing and what it may have been like.

Here's Izzy's reports.

Now, fossil one, it looks like it had wings, so she thought that this animal could fly.

She says, "Its legs look quite short, so I don't think it could move very fast on land.

Judging by the shape of its skull, I think it had a pointed nose instead of a beak.

I don't think it was a bird.

I think it was a predator because it looks like it had sharp teeth and it probably ate smaller flying and walking animals." The second fossil here, she says, "This animal had long horns, which I think we use to protect it from predators.

The skull looks very thick and heavy, so I don't think it could move very fast.

It's not a very streamlined shape like a fish or bird, so I don't think it could swim or fly.

It probably walked on land.

It looks like it had lots of molars for grinding down plants.

It has no canines for catching and tearing away at other animals flesh, so I think it was probably a herbivore.

I think it was lightly brown or green to blend into its surroundings and hide from predators.

Based on the size of its horn, I think it would've been taller than me, but not too big to fit in my school hall." The third fossil here, she says, "I think this animal is probably a predator because it has sharp claws at the end of its toes.

It definitely walked and ran on land, and I don't think it lived in the sea.

I think it was a carnivore that ate other animals on land.

It was very big, so it probably ate quite big animals too.

I think it would be very big because its foot is so large, maybe even taller than my school.

It must have been a vertebrate animal because it had an internal skeleton.

I think it could have been a mammal or a reptile.

And fossil four, "I think this animal is probably quite big because it's poo is 30 centimetres long." Oh, yes, of course, this is a coprolite, isn't it? It's an example of some poo.

"Larger animals have larger poo.

It was definitely a predator because there are remains of fish in its poo.

It could have been a carnivore or an omnivore.

Since it ate fish, I think it might have lived in water, or possibly very near to water.

I think it may in a very large fish, but it could also have been a mammal or reptile that lived near the ocean or a river." So now that we've broken down each of the bits of evidence about these fossils, you can have a little think too.

Did your answers go into enough detail here.

Where you were able to answer you each bullet point when you were discussing each fossil? Now, if you're not too sure, you can always go back here and use some of Izzy's notes to improve your own.

You can continue the video when you're ready.

So let's summarise our lesson.

Fossils are our best form of evidence about the Earth's history, including the history of life.

They can give us clues about living things that inhabited the earth millions of years ago.

Scientists can use the fossil record to tell them how long life has existed on earth and palaeontologists use evidence from the fossils that they find to propose theories about living things from the past.

Now, I hope that you found some elements of this lesson particularly interesting, especially the part about how the T-Rex could have actually been covered in feathers.

There's lots of evidence to suggest that all of the dinosaurs were reptiles, but there were also many different feathered examples in each of the family trees as well.

Who knows, maybe using some of this evidence, you might want to go forward and discuss and dig up things even further, maybe becoming a palaeontologist of the future.

Well, I hope that you go digging and searching for more clues and data, especially in fascinating fossils.

I've been Mr. Wilshire.

Thank you very much for listening.