Lesson video

So in this unit, we have been studying evolution, and today we're going to focus on the evolution of humans, and then we're going to see what effect us humans and our evolution has had on other organisms. You will need a piece of paper, a pencil, a colouring pencil so you can mark your work like Summer and a ruler.

We will also need these star words for the lesson.

So our star words today are evolution.

I'm going to say it and you're going to say it: evolution, variation, adaptation, gradually, and impact.

Now lots of these words we'll already be familiar with because we've learned about them so far throughout our lessons.

So evolution we know is the gradual change of organisms over time.

Variation is the same as differences.

So when we talk about variations, we mean the differences between organisms. An adaptation is something that helps an organism to survive.

Can you think of an adaptation? It can be of any animal.

What's an adaptation that a shark has? What's an adaptation that an elephant has? Can you think of one? Great.

So for example, a shark, an adaptation that a shark has is really sharp teeth to help it rip into its prey.

Gradually means really slowly.

We've spoken about this word before, but it's going to be really important in this lesson, okay? Gradually means really slowly.

Say that with me 'cause it's really fun to say.

Gradually means really slowly.

Good job.

And our last word is impact.

A impact means the effect something has.

Okay, so I'm trying to think of an example for you.

If I walked into my mom's bedroom with a cup of tea, that would have an impact on her, that would have an effect on her.

It would probably make her smile, okay? So impact means the effect that something has.

This is the structure we are going to follow in today's lesson.

We're going to start with our recap like we always do.

Then we're going to look at the evolution of humans.

Then we're going to look at some human innovations, and I'll explain what that means and we get to it.

We're going to look at the impact of humans on plants.

And then we're going to look at the impact of humans on animals.

So let's start with our recap.

So we've just gone through evolution in our star words, so I want you to try and remember and say it to your screen.

Evolution is the process by which things gradually change over time, or I should have said living things.

Well done if you got that correct.

Okay, and so far in our lessons, we've looked mostly at the example of evolution in finches.

Those lovely birds that Darwin found on his island that are our picture on this screen.

Okay, and we looked at how the shape of finches' beaks has changed gradually over time.

Now, the reason for that is evolution.

And we can explain why that happens if we think about the different types of food that finches are eating.

The shaped beaks that are best adapted to the food on the island are the ones that you see most in the finches.

And over time those will become the only ones that are there in the finches.

Okay, we need to think about that today when we're thinking about our humans.

So our main adaptation in finches was beaks.

In humans, it's going to be different because we don't have beaks, but we're going to think about which parts of our anatomy, of our body have helped us to become well adapted to the environments we've lived in.

Okay.

There's our definition.

We've also looked at the fossil record.

So the fossil record is a collection of fossils found at different ages in rock, and that's used as evidence for evolution.

So what we're learning about in this unit, all of it has come from fossil evidence.

If we didn't have those fossils, then I wouldn't be able to sit here and teach you about evolution because we wouldn't know how humans have changed over time.

We wouldn't be able to see it in the fossils.

We've also learned about the animal kingdom, which is split into invertebrates and vertebrates.

Okay, so we then zoomed in on vertebrates, which are organisms with backbones like us, just having a little feel of my backbone.

And then we looked at the five main groups of vertebrates, which are, I was about to tell you, but actually this is the chance to test your memories.

Can you please write down the five main groups of vertebrates on your pieces of paper, please? You can see they're labelled: one, two, three, four five.

Pause the video and have a go at doing that now please.

Let's see if you were correct.

Number one is fish.

Number two is amphibians.

Remember that "ph" sound is spelled with a P-H.

Number three is reptiles.

Number four is birds.

And number five is mammals.

Which group are we in? 'Cause we're looking at humans today.

Which group are humans in? We are mammals.

Good job.

We also looked at geological eras of time.

And we saw a lovely example in the work from last week of a timeline, which is what you can see.

We looked at the four main geological eras, which were the paleo.

Oops, I just made a mistake there.

That's okay because we all make mistakes.

See, I've been saying that for weeks, and now you have to believe me because even I make mistakes.

we looked at the Proterozoic era And what was my special way of remembering that proto goes first? If I'd remembered that, then I might not have made that mistake because pro is someone who's really good at something, and pros come first.

So Proterozoic era is the first one.

Our next one, which was 530 million years ago was the Paleozoic era.

Then we learned about the Mesozoic era.

Which group of animals first evolved in the Mesozoic era.

I have a trick, a sticky way of remembering.

It began with M.

Mesozoic begins with M, so it's the mammals.

Great.

And then we have the Cenozoic era, which is the era we'll be looking at today.

Okay, so we learned that geological areas are the space of time between two mass extinction events, and a mass extinction occurs when most of the organisms on planet earth die out.

So the Cenozoic era, 66.

4 million years ago, started when the dinosaurs became extinct.

Okay, so we're going to zoom in on that era now because that's when humans evolved.

So here we go.

Here's our zoom in on the Cenozoic era.

So first up we have dinosaurs becoming extinct.

Then 2.

5 million years ago, that's when we had our first human-like animals.

Okay, so they're not the same as humans today, modern humans, which evolved 0.

2 million years ago like you and me.

I just did that the wrong way back, like you and me.

I'm making lots of mistakes today.

I hope that it's giving you a giggle and not making you roll your eyes at home.

Now I forgot what I was saying.

Human-like animals, 2.

5 million years ago were not the same as modern humans.

We're going to learn a little bit about the differences between human-like animals and modern humans today.

In fact, that's what we're going to do first.

So we're going to talk about the evolution of human beings, how humans gradually changed over time.

Got two pictures here.

The first one is a picture of our first kind of human-like animals.

You can actually see the species name for each at the bottom, but we're not going to worry too much about that, okay? And the second picture is an example of what a modern human would look like.

Okay, so can you please write a list for me on your piece of paper of all the differences you can spot between these two organisms? So for example, I can see straight away that there's a difference in size.

Okay, you're going to make a list of all the differences you can spot.

Can you please pause the video and complete that task for me now? In fact, I'm going to make the screen full so you can see it nice and clearly.

Great.

Now I've got four differences on the next screen.

I think that you would have found many more than me, okay, and that's great.

So these are some of the differences that I spotted: longer legs.

So I'm talking about the modern human.

It has longer legs.

It's taller.

It's got better tools.

Did you notice the difference between the tools? One of them is carrying a bone.

It looks like an animal bone, and the other one's got a spear.

Okay, and there's also less hair in modern humans.

Now, like I said, you probably got many more differences than me, so you can give yourself a tick for all of the differences that you found.

If you missed out any of these four differences, so longer legs, taller, better tools or less hair, could you just pause the video and add them in for me now? Now, there's a reason that I've chosen these four.

I chose them because they were the most obvious I think, but we're going to focus in actually on the first three, so longer legs, taller, and better tools.

These are differences.

And that's the word I keep using, but actually there's a star word that would be better.

Think back to our star words.

What do we actually call, in science and when we're studying evolution, the differences between organisms? What was that star word? If you know, say it to your screen.

Variation, good job.

Okay, so we can see that there's variation between these two organisms. Now my next question is, is any of this variation an adaptation? What do I mean by that? Well, let's think back to our star words.

An adaptation is a characteristic that helps an organism to survive.

So would any of these things help our homo sapiens, so that's the species name for modern humans.

Would any of these adaptations helped our homo sapiens to survive? How would longer legs help our homo sapiens to survive? How would being taller? How would better tools? How would less hair? Well, longer legs would help humans to run faster? So that would be good if you're running away from a predator or if you're hunting prey.

Being taller might help homo sapiens to survive because again it might mean that they are more, they're bigger in comparison to their predators, which means they have a better chance of fighting or scaring them off.

Better tools might help them to survive because it means that they can get more food.

They might be using their tools for hunting, which means that they can more effectively hunt their prey.

I think a big spear like that is probably more effective than a bone, and less hair is a bit of a weird one, but we will talk about this.

Less hair is definitely a difference, but scientists are not a hundred percent sure yet if less hair is an adaptation or I should say why less hair is a good adaptation, why having less hair would have helped humans to survive.

There are a couple of theories.

So one of the theories or suggestions is that maybe it helped humans to control their body temperature, having less hair, so the were less hot.

Another theory, which is kind of gross is that it might have helped to reduce the number of parasites on their body.

So a parasite is a kind of organism that lives off another organism.

So examples of parasites that we might be familiar with are mosquitoes.

They live off other organisms cause they suck their blood or maybe nits.

Nits or lice live off other organisms because again, they live in people's hair or fur, and they suck their blood.

So one of the suggestions is that if humans had less hair then they would have had less parasites to worry about, but we're not a hundred percent sure of that.

So, we know then, we can see that homo sapiens, modern humans are better adapted to survive.

If you were to put both that early human-like organism and a modern human in the same environment, which one do you think would survive? Which would last longer? Which would be able to outrun its run its predators? Which would be able to hunt its prey? Which would win in a fight? And the answer we can see is homo sapiens, modern humans.

But modern humans came from those early human-like animals.

They evolved.

So the ancestors of modern humans looked that organism on the left.

This happened very, very gradually.

Remember that was our key word.

What does that mean? It means it happened slowly.

We're not talking about, you know, a couple of generations here.

We're not saying that anybody's grandparents looked like that organism on the left.

We're talking millions of years, okay? Now you might remember from our timeline that 2.

5 million years ago was when we saw those first human-like animals evolving.

So it took 2.

5 million years for those human-like animals to gradually change and adapt into modern humans with longer legs and better tools and less hair, okay? And actually it's been another 0.

2 million years since modern humans first evolved, and we're still changing today, okay? Now there are lots of organisms in between these two organisms I've just shown you.

I'm going to show you an idea of what we think those might have looked like.

So I should say at this point that these are drawings.

They've been drawn by scientists as a good estimate, or guess of what these organisms used to look like.

Now, the reason that we're able to make these estimates is because of the fossil record.

So because of the fossils and the preserved remains of these organisms, we're able to see how they might have looked and how they might have changed over time.

So here are some ideas.

So you can see gradually over time, height is increasing.

Length of legs is increasing.

Hair is reducing.

Humans are becoming more upright, and you can see they have different tools in each picture.

And those tools are becoming more complicated and harder to make every time.

I've got some questions for you now.

If you want to pause this video and study this picture a little bit longer, then you can do that now.

Otherwise I'm going to move on to the questions.

These, this is your question.

I said questions, but there's just one.

I would like you to answer this question using more than one sentence, okay? It doesn't need to be a big long paragraph, but this explanation should be more than one sentence please.

So the question is why are modern humans different to their ancestors? So I'm just going to flip back.

Why is our homo sapien different to its ancestors? So you might want to use some of the differences you've written down already as examples in your answer.

Your challenge is to try and use the key words below in your answer, so those key words are evolved, adaptations, survive, and gradually.

We'd like you now to pause the video and have a go at answering the question above.

We're not going to be doing much writing today.

Okay, so I want you to make sure that the writing that you are doing, you are thinking really hard about trying to use all four of those keywords.

You might want to write an answer.

Check if you've got the keywords, and then maybe go back and add them in or edit your answer if you've missed one out.

Pause the video and have a go now.

Great, good job.

Now I'm going to show you my answer.

Yours might not be exactly the same as mine, and that's okay.

We'll all have written something slightly different, but let's see if we got the same key points.

So this was my answer.

I'm going to read it to you.

"Modern humans are different to their ancestors." And then I put in an example, "For example, "they have longer legs and learned to make tools.

"These adaptations make them more likely to survive "in their environment and would have evolved gradually "over millions of years." So that's my answer.

I've included an example of an adaptation.

So I've included longer legs and tools, and I've included all four of my key words.

Well done if you managed to do that too.

This would now be a really good chance for everybody to pause the video and redraft their answer.

Okay, so if we redraft something, it doesn't mean that our first answer wasn't really good, but we can always make our answer even better, okay? And in our lessons and in our lives, we always want to go from good to great, okay? My answer is good.

I could make my answer even better too, okay? So we're all now going to pause the video and have a chance to make our answers even better.

You can use mine on the screen to help you make yours even better.

Maybe you could add in one more key word.

Maybe you can add in an example.

Maybe you can just read it through carefully and see if you can reword it, so it's even clearer.

Pause the video and redraft your answer now.

Great, good job.

Next we're going to look at human innovations.

Okay, I'm going to explain what I mean by that.

Now I was saying something in the last section of the lesson that isn't a hundred percent accurate.

So I'm going to apologise.

I'm going to be really accurate now, okay? So a tool is not actually an adaptation because a tool is not a part of the organism, right? And our definition for an adaptation is a characteristic of an organism that helps it to survive.

However, a tool is an example of an innovation, which is a bit like an invention.

It's like a new thing.

And the actual adaptation that we should have been talking about, but we didn't because it was quite hard to see from our pictures, is brain size.

Something that we couldn't see in those pictures is that humans' brain sizes have evolved to be bigger over millions of years.

And because our brains have evolved to be bigger, it means that we've become more intelligent and that increased intelligence is the adaptation, okay? So bigger brains and increased intelligence, that's the adaptation.

And that adaptation has allowed us to make tools.

Okay, we're smarter than our ancestors.

So we can figure out and learn how to make better tools.

And it wasn't just tools that were the only things that humans learned how to do.

We learned how to do lots of different things, which helped us to survive.

So here are some of the things we learned to do.

We've already spoken about tools.

So tools helped us to gather food and to hunt.

Okay, this meant we could get more food.

And so we were more likely to survive.

Another innovation was that we learned how to make and use fire.

Why do you think this might have been useful? Why would fire have helped us to survive? So fire was useful for a number of things.

It meant that we could keep warm in environments that were cold.

It meant we could scare away bigger animals.

So bigger predators that we might not have been able to actually fight.

We could scare away with fire.

And it also meant we could cook food, and that's important because when you cook food, you get more nutrition out of it, so you're more likely to survive.

Okay, so that's two things: tools and fire.

We also learned how to make clothing and shelter.

And that meant that we could protect ourselves from the weather.

And lastly, one of the most important things we learned how to do was to speak our own language.

Okay, now this is important because humans being able to make sounds to make a language, which they could then pass on to their children meant that we could teach our children things so that they could also survive.

If just one human figured out how to use fire for example, it wouldn't be very useful unless that human could use their language to explain and pass on that innovation to other generations and to other humans.

So having knowledge of each of these things helped humans to become able to survive and grow in numbers, which meant they could spread out all over the earth.

Humans are the only organism that you find in every single corner of the earth.

We have been so successful because of these innovations that we've been able to spread out all over the earth and move across the globe.

Okay, I have some questions for you.

Take a mental picture of those four innovations before I ask your questions.

So, what four things did our ancestors learn to help them to survive? And then I'd like you to write a sentence please about how each of those things helped humans to survive.

So I've written a sentence down at the bottom of the page for you.

You can use it if you like.

So for example, you could write, humans learned to mmmm.

This helped them to survive because.

Pause the video and complete that now for me, please.

Great, good job.

Let's check your answers.

So our four innovations were to make tools, language, to make fire and to make clothes and shelter.

Give yourself a tick if you've got each of those.

Well done, and no problem if you missed one.

Just correct it with your different colour.

Now, I haven't written the exact answer for the next bit because you all might have written different sentences.

Okay, but we can talk about some of those now.

So answers that you could have put were humans learned to make tools.

This helped them to survive because they could, you could have written, they could get more food.

They could hunt larger predators.

They could, they were more successful at hunting or maybe it helped them to do lots of different things.

Okay, well done if you've got any of those down.

You also could have written humans learned to use language.

This helped them to survive because it meant they could pass on the things that they learned to their children or to different generations.

You also could have put humans learned to make fire.

This helped them to survive because, and there are three different things you could have written for this.

This helped them to survive because it helped them keep warm.

It helped them scare away big predators, and it helped them to cook their food to get more nutrition out of it.

Well done if you got those.

You could even pause the video and add some more detail if maybe you missed out one of those reasons.

And lastly, humans learned to make clothes and shelter, and this helped them to survive because it meant they could stay warm or protected in different types of weather or environments.

Well done, you are working really hard.

We are going to move on now to the impact of humans.

So we learned that humans were so successful as a species that they managed to spread out all across the earth.

Now that had an impact, that had an effect on plants and animals and other organisms that were living.

Our next lesson is going to be all about the impact that humans are having, okay, but we're going to start to look at that impact this lesson.

So we're going to start with the impact that humans had on plants.

So about 10,000 years ago, humans began to affect the plants and animals around them and take a number of actions to make them, so the plants and animals, help humans to survive.

So for the first time, one living creature, or one species, started to change the world to help them survive.

Humans took the seeds of plants that they liked to eat, so not just any plants, seeds of plants that they liked to eat, and they began to plant them in specific places.

They began to plant them where they would get enough sunlight and where they would get enough water in order to grow.

So before this, humans were something that we call hunter gatherers.

What do we call them? Hunter gatherers.

This means that they spent most of their days having to move large distances to hunt their food and to gather their food, so to pick berries or pick wheat.

Okay, and their food was scattered far and wide.

That's why they had to go those long distances to find it.

However, when humans started taking the seeds from the plants that they like to eat, they started putting them in one place.

They would put them in that place where like we learned, they get enough water and sunlight, but also in a place where it was easy for them to go back to.

So later they could go back, they could gather them up, and they could store them so they had enough food to eat.

And that meant that they didn't have to go out and gather every single day because they could go and gather from this one patch and store it up for a longer time.

The food that they did this with was things like wheat, which we use to make bread and barley and lentils.

So what this meant is that there were a lot more of these plants because humans helped them to survive and grow and reproduce.

So it was kind of like we were giving them a helping hand.

We were helping the seeds and these plants to grow, and we were choosing our favourites.

And so our favourites to eat grew and grew, and there were lots more of those kinds of plants.

So that's the impact that humans had on plants.

I wonder if you could draw a picture or a diagram to represent this.

So can you draw a picture, a diagram, to represent that kind of story that I just told you.

Okay, I'm going to simplify it and tell it one more time.

So that this time in your head you can be thinking, what would I draw to show this? So we start off with humans as hunters and gatherers.

So that might be the first picture that you draw, and they need to travel far and wide to hunt and gather their food.

So you could pause the video and draw a picture for that now.

Or you can listen to the entire explanation and then pause the video at the end and draw your picture.

I don't mind.

The next thing you might want to draw is something to represent humans choosing their favourite foods and planting them in one place.

Pause the video and draw that picture or wait until the end.

And then the next thing you might want to draw is those new plants growing and the humans storing them up.

Pause the video and draw your picture or your diagram to represent that for me now.

Don't worry if you're not good at art.

I'm not the best at art, but it doesn't matter.

Okay, these pictures are just to help you explain something.

Pause the video if you haven't already and do those now.

Great, good job.

The next thing we're going to talk about is the impact of humans on animals.

So we've got four animals here.

We've got some chickens, some sheep, some horses and some cows.

Okay, and that's because those are the animals we're going to be talking about.

So humans also began to look after certain animals that they found useful.

So today we're quite used to having animals that we might have to look after in our homes.

Humans today have pets.

So you saw an example of one of my pets at the beginning of this lesson, and I'm sure that many of you have your own pets at home.

And we choose to look after those animals.

There are also farm animals around, okay.

So animals that live on farms and are looked after by farmers.

Now, we haven't always looked after animals as a species, and very early humans, there were only wild animals around, okay? So that's the difference.

Wild animals don't need looking after by humans.

But there are some animals that do need looking after by humans, and humans began to look after certain types of animals.

They chose animals to look after that were useful.

So ones that they could eat or drink their milk from, or use their skins for clothing, for example.

So it's believed that the first animals to be looked after by humans are goats and sheep and later chickens.

And as a result, there are many, many more of these animals on the world and on the planet today because we found them useful, and we've looked after them for thousands and thousands of years.

You have four pictures on the board.

Your last task is can you write a few notes about why each of the animals on the screen is useful? Can we eat a part of the animal? Do they help us with something? Can we use any of their products? Pause the video and have a go now.

Great, so let's just discuss what you might have written before we end our lesson.

So chickens are useful.

You might have written that their feathers can be used in things like pillows or duvets.

They can be eaten, so people, some people eat their meat, and their eggs can be eaten as well.

Sheep, again, another animal where we can eat the meat.

And also their wool is really useful for making clothes and materials.

Horses, now, horses, we don't eat the meat of horses.

However, horses are really useful because they help to transport things, so we can ride horses and they helped humans to get around or to do things like drag machines or carts for them.

Cows, cows are really useful because again, they're an animal that some people can eat, and they also produce milk.

Well done if you got any of those correct.

That brings us to the end of our lesson.

Well done for working so hard today.

I am really, really impressed with the work that I've been seeing so far.