Lesson video

Hi everybody, my name is Miss Simkin.

I am going to be teaching you science, and I absolutely love science.

My favourite thing to learn about in science is animals, especially animals that live under the sea, marine animals.

In fact, I love marine animals so much that I learned quite an unusual hobby.

So my favourite hobby is to go scuba diving.

Which if you don't already know, is when you put on a funny wetsuit, you put a tank of air on your back, and then you breathe from the tank of air through something called a regulator that goes in your mouth.

It makes a funny sound like this.

And it means you can breathe underwater.

And I absolutely love doing that, I've got to see some amazing things, really colourful fish, turtles rays, and even some small sharks.

Unfortunately, I haven't been doing very much scuba diving recently.

Like all of you, I've been spending a lot of time inside my house.

But that's okay, because it means I've had lots of time to read books, which I love doing.

To do lots of baking.

And also to spend time with my slightly crazy dog called Charlie, who you might get to meet in some later videos.

I'm really excited to be teaching you science.

So, let's get started.

Our first topic for the next six weeks is how fossils and animals change over time.

Our lesson title today is, what is the theory of evolution? So this is the question that we're going to be able to answer by the end of the lesson.

A theory is what scientists think might explain something that they see.

And we're going to be building on what you already know about organisms and explaining how they change over time.

For this lesson, you will need a piece of paper, it can be either a scrap piece of paper or a notebook, if you have one, and a pencil.

If you don't have those things, then pause the video now and go and get them.

Great.

Once you're ready to begin, we will start our lesson.

Now, this might seem a little bit strange to begin with, having your teacher inside your phone, or your computer, or your tablet screen, and doing all your learning online.

But that's okay.

It is going to take some getting used to for both of us.

I'll make sure that I am really clear and really careful with my explanations to make everything as easy as possible for you.

And you'll see that our lessons are going to follow the same structure each time.

So you're going to get ready and used to things really easily.

And I hope that through this journey, you are really patient and kind to me as well, because I might make some mistakes as we're going along, 'cause I need to get used to it too.

Let's take a look at what lessons structure we're going to follow today.

So we're going to start with our star words, which is our key vocabulary for the lesson.

Then we're going to have a look at Darwin's observations.

And then we're going to learn how his observations led him to create his theory.

Then we're going to look at some different examples of evolution.

And then at the very end of the lesson, you'll be able to take your post-lesson quiz to see how much you've learnt this lesson.

We will also revisit our star words right at the end to recap before you take that quiz.

These are our star words for today.

This is our key vocabulary.

So we'll start and end every lesson with our star words.

And sometimes, I will define them, I'll tell you what they mean right at the beginning.

Sometimes, we won't learn what they mean until in the middle of the lesson as part of our learning.

Okay? So our first star word today is an organism.

An organism is a living thing.

It could be a plant, it could be an animal, it could be a microorganism.

An organism that's so tiny you need a microscope to see it.

A characteristic is a physical feature.

So for example, my eye colour is a characteristic that I possess.

So my eye colour is blue, and that's one of my characteristics.

Variation, is the differences between species.

So if you have a different eye colour to me, then that's a variation between us.

An adaptation, is a characteristic that helps an animal to survive in its environment.

So the example I gave of a characteristic was my eye colour.

But that's not an adaptation, because it doesn't help me to survive.

So it has to be an adaptation that helps the animal to survive.

So if we think about the fur colour of a polar bear, that would be an adaptation.

'Cause that characteristic helps the polar bear to survive.

If the polar bear's white fur matches its background, it allows it to camouflage and to blend in with its background, which helps it to hunt its prey and stay undetected.

And then we have the star word, species.

So a species is a group of living things that can breed together.

So humans are a species.

Well, cats would be a species, but they don't have to be animals.

We have species of plants as well, like grass, grass is a species.

And our last star word is evolution.

That's the focus of our lesson today.

So by the end of the lesson, we will be able to define what evolution is.

Our first section we're going to look at, is Darwin's observation.

So, this is a picture of a type of bird called a finch.

And these are a type of bird that a scientist called Darwin, made very important observations about.

I'm going to explain those observations in a moment.

Darwin, was a scientist who was born in 1809 in Shrewsbury in England.

And from a young age, he was interested in lots of different kinds.

When he was 22 years old, he went on a trip on a boat called the HMS Beagle and he travelled all around the world.

He saw lots of different animals, but he is most well known for the discoveries and the observations he made about these finches.

So he discovered that different animals seem to have different characteristics, that meant they were well suited to their surroundings and their environment.

For example, he noticed that different finches all lived on islands that were close to each other.

However, each of the islands finches had different beaks.

So you can see here in this picture, some of the finches have a kind of sharp pointier beaks, and some of the finches have thicker, stronger, beaks.

They look stronger.

He also noticed that each of the different islands had a different type of food.

And so, he decided that over time, one type of finch must have existed.

And then over time, they had changed, so that their beaks suited the island and the type of food that was on that Island.

With this in mind, he came up with his theory of evolution.

Here are some notes that recap what we've just spoken about.

You can use them to help you answer the questions on the next slide.

So you can always go back to this part of the video, if you need some help, when you're answering your questions.

These are the questions that I would like you to answer.

Please write them on your piece of paper.

So question one, when was Darwin born? Question two, what was Darwin interested in? Question three, how old was he when he sailed on the HMS Beagle? And then, I'd like you to complete the following sentences.

Darwin realised that different.

seem to have different.

that meant they were well suited to.

This helped him come up with the theory of.

Please write in full sentences when you're answering that section.

And remember, if you can't quite figure out the answers, then go back to the last part of the video to hear it again.

You can now pause the video and write your answers down.

Great.

When you're ready, we're going to mark our work.

If you have a different colour, you might want to this to tick or fix.

Otherwise, you can just use the pencil that you have to.

So the first answer, was Darwin was born in 1809.

The second answer, is darling was interested in lots of different types of animals.

Then number three, Darwin was 22 when he sailed on the HMS beagle.

And then these were the full sentences.

Darwin realised that different animals seem to have different characteristics that meant they were well suited to their surroundings.

This helped him come up with the theory of evolution.

But only if you've got those answers right, you can give yourself a big tick, if you did.

If you made any mistakes, that's okay, mistakes are the best way for us to learn.

All you need to do is to get your different coloured pencil and correct your answers.

You can use the answers on the screen.

And if you need a little bit more time, just pause your video to do that now.

The next part of our lesson, is to look in a bit more detail at Darwin's theory.

It's time for a demonstration.

But I need to grab some things before we begin.

First of all, I'm going to get my lab coat.

I always wear my lab coat for demonstrations.

And then, I'm going to get my special science box.

So, this is my special science box, and it is covered in penguins.

Let's see what's inside our special science box for today.

So, we have a box with a hole cut in it.

We have a beaker full of rice that's not cooked.

And we have a metal spoon.

And some tweezers.

So, I'm going to use this equipment to demonstrate some of Darwin's observations and ideas about birds beaks.

So, I'm just going to put it like this, so that you can see really clearly what I'm doing.

So, I'm going to take this box with the hole in it.

I'm going to put the rice inside it.

And then I'm going to close the box up.

Now, we're going.

Oops some rice is falling out.

We're going to imagine that this box is like a kind of fruit that you might find on the island.

Okay? And inside, the fruit seeds, which are represented by the rice, okay? And the finches that Darwin was observing, need to eat the seeds inside the fruit in order to survive, that's their main food source.

But they need to be able to get them out of the fruit, or in this case the box, in order to eat them.

Okay.

Now my spoon and my tweezers are going to represent two types of birds beak.

This is representing kind of a long, pointy beak, and this is representing a big, wide, strong beak.

Okay? And we're going to see, which bird's beak is able to get the seeds out of the fruit.

I'm going to start with my spoon.

And I'm going to see if I can get my seeds out of the box.

One's fallen out.

But I can't get the other seeds out of the box, because my spoon is too big, my beak is too big.

It's not the right type of beak in order to get the seeds out.

Let's try now with my tweezers representing my thin, pointy beak.

They've managed it.

So, this shows that only the birds with the long, thin beaks would be able to survive on the island that has the fruit like this.

These birds, with the big, chunky beaks, wouldn't be able to survive, because they wouldn't be able to get their food.

That means, eventually, they would die.

These beaks, the birds with these beaks, would survive.

Because they'd be able to get the food that they need to survive.

They would then be able to reproduce and have offspring, which is another word for children or babies, and then they would pass on their beaks to those children.

So their children would have beaks that look like them.

And eventually, there would be none of the birds with these beaks left, cause they all would have died.

And we'd only have birds with these beaks left that can survive.

So, here are two diagrams that explore the ideas and the demonstration a little bit more.

This was the finch in our demonstration who had a beak shaped like a spoon.

And this was the finch in our demonstration whose beak was represented by the tweezers.

Okay.

Now, the reason we have an X over of this finch is because, it's beak wasn't well adapted to its environment, it didn't allow it to get the correct food.

So the example I used was getting seeds from fruit.

But it could be going into a log and getting insects out or something like that.

And this bird's beak, was not well adapted to that, it wasn't well suited, and so it didn't survive.

This bird's beak was well adapted and so this bird survived.

What that means, is that over many, many generations, we see fewer of birds with this type of beak, and more birds with this type of beak, the well-adapted beak.

Because this bird is more likely to survive and then reproduce and pass those characteristics onto its offspring.

Now, there are two things that I want to clarify about this theory that can be a bit confusing.

The first, is that the birds or the organisms, they don't choose to be well adapted or not.

They don't choose the kind of beak that they have, it's just luck.

So, the bird with the bird with the tweezer beak was really lucky, and the bird with the spoon beak was not so lucky.

Okay? So it's just luck, it's not a choice.

The second thing I want to be really clear is that, this change over time, that we see within the species, is happening over a really long stretch of time.

I'm talking thousands and thousands of years.

So, let's read our comprehension that recaps those main ideas, before you answer your questions.

Only the bird with the long beak can get the seeds out of the fruit or the grubs found deep in the wood.

This bird is better adapted and would survive longer and reproduce more, over time.

Birds without this characteristic would die out, and the longer beaks become more common until all finches have a long beak.

So these are the steps of Darwin's theory of evolution.

Step one, not all individual species are exactly the same.

There is variation between them.

So that was one of our key words.

Step two.

Individuals who are best adapted to their environment are the most likely to survive.

Step three.

These individuals are more likely to reproduce and pass on their useful adaptations to their offspring.

Individuals who are poorly adapted are less likely to survive, so our spoon beak finches.

Over time, the characteristics that help survival become more common and a species gradually changes.

Given enough time, these small changes can add up to the extent that a new species altogether can evolve.

You could now have a go at answering these questions.

So I would like you to complete the following sentences using the words at the bottom of the page.

So this is your word bank here.

And you need to fill in the gaps in each of these sentences.

Please write out your whole sentence, and then underline the words that are missing.

You can pause the video and have a go at doing that now.

Great.

Once you're ready, you can get your different coloured pen or pencil, if you've got one, and we can mark.

Let's see if you got the correct answers.

The first word that was missing was same, and then it was variation.

In number two, it was adapted and then survive.

In number three, it was reproduce and offspring.

In number four, it was adapted and then survive.

In number five, it was characteristics and changes.

And in number six, it was time and species.

If you've got those correct, give yourself a tick.

If you've made any mistakes, that's okay, mistakes are how we learn, just correct your answers.

And if you need a little bit more time to write down the correct answer, just pause the video and do that before we move on.

The next thing we are going to look at is, examples of evolution.

So, we are going to have a look first at this representation, this diagram, with the fox and some mice.

So I'm just going to read to you what it says by each picture.

So in this first picture, we have a fox who's got a mouse in his mouth and some mice on the floor and it says, the white population is greater than the dark mice population.

And here you have a representation of the number of my mice that are shown in this picture.

So I can see that there are three dark mice, and one, two, three, four, five white mice.

Okay? And the fox is a predator of the mice, it's eating the mice.

It says here, some mice are eaten by the fox.

And I can see here that he's got a white mouse in his mouth.

And in this next box, we have fewer mice, because the fox has eaten some of them.

So it says, white mice are more visible to the fox.

Thus, white mice are eaten more.

That makes sense.

So, there's variation between the two mice here.

Their characteristics are different.

One of them has dark fur, one of them has white fur.

And the white mice get eaten more, because they're more visible to the fox.

So then this arrow says up here, the surviving mice reproduce.

So we have more mice again.

The next generation contains a higher number of dark mice.

That's interesting.

So, can you answer these questions? What happens to the number of white mice? You can see the numbers down here.

What happens to the number of black mice? And which mouse is better adapted and why? Pause the video and have a go answering those questions now.

Great.

When you're ready, let's check our answers.

So, the number of white mice decreases.

The number of black mice increases.

And, the answer to number three is that the black mice are better adapted as they are less likely to be eaten, because they are harder to see.

Well done if you got those right, give yourself a big tick.

If not, that's okay, just fix your answers.

So, correct them using the answers on the screen.

When you're ready, we will have a look at another example.

So, this example, is about long-necked giraffes.

Giraffes are very famous for having their long necks.

So, let's have a look at this.

Many people believe that giraffes have long necks because they evolved long necks over many generations.

Explain how giraffes may have evolved their long necks over time.

So, you've got some key words here to help you.

Variation, adapted, survive, reproduce, offspring, characteristic and time.

So see if you can use those words in your answer.

And before you begin, have a think about, what giraffes eat, they eat leaves at the top of trees, and how their long necks would help them to survive.

What would their long necks helps them to do? Okay, so the long necks are the adaptation in this example.

And then, what happens over time? Pause the video, and have a go at explaining this now.

Please use full sentences.

And when you're ready, we'll have a look at an example answer.

So, this is an example of a very good answer to this question.

So, if you got parts of this right, then give yourself a big tick.

I would like everybody to have a go at redrafting their answer to this question.

So that means, writing it out again.

Because even if you've got lots of this right, we can always improve to get the perfect answer.

So I'm going to read it to you now.

In the past, not all giraffes were the same, some had short necks and some had long necks.

This is called variation.

The giraffes with long necks were more likely to survive as they could reach more food.

These giraffes reproduced and passed on their useful adaptations to their offspring, whilst the short-necked giraffes died out.

Over time, the long neck characteristic became more common until all giraffes had long necks.

So well done if you got any of those ideas.

And, now, pause the video, so you have time to redraft your perfect answer.

Great.

Before you do your end of lesson quiz, I would like us just to recap our star words.

Okay.

So, these are the star words that we looked at the beginning of the lesson.

It might be a good idea to write some of these definitions down to help you remember them when you do your quiz.

So, an organism is any living thing.

A characteristic, is a physical feature of an organism.

So for example, eye colour, or hair colour, or neck length.

Variation, is the differences between living species.

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

Evolution, is the process by which organisms change over a period of time.

And a species, is a group of organisms that can breed together.

Remember, those can be both plants and animals.

Well done for all your hard work today.

I'm really impressed and I'm already excited to see you at the same time next week for our next science lesson.

Have a lovely day.