Lesson video

This lesson is called Impacts of climate change on biodiversity and is from the unit Climate change and biodiversity.

Hi there, my name's Mrs. McCready, and I'm here to guide you through today's lesson, so thank you very much for joining me today.

In our lesson today, we're going to consider the impacts of climate change on biodiversity and also look at the consequences for plants and animals.

In our lesson today, we are going to come across a number of keywords, and they're listed up here on the screen for you now.

You may wish to pause the video to make a note of them, but I will introduce them to you as we come across them.

So in our lesson today, we're going to look at what an adaptation is and how the adaptations of organisms and climate change interact.

And then we are going to move on to look at how climate change impacts biodiversity.

So, are you ready to go? I certainly am, so let's get started.

Species living in different habitats have different features, as you can see from just a small selection in the pictures on the screen.

And the features that enable the species to live and thrive in the conditions that they find within their habitats are called adaptations.

So habitats are the spaces where organisms live and the adaptations are the specialist features that those organisms have which allow them to survive successfully in their environment.

So the chameleon, for instance, is well camouflaged for its environment, and the polar bear has thick fur and a layer of fat under its skin to keep it warm in the cold environment.

And all of these different things and plenty more besides are adaptations.

They are specialist features.

So camels and cacti live in very hot, dry areas of the world, in deserts, and cacti are specialised for their environment because they have no leaves, the leaves have been turned into thorns, they have a very deep root system so they can find water stored at depth in the soil, and they have a very low surface area, so they lose as little water as possible from their surface.

Whereas camels living in the same environment have different adaptations.

They store water and food in the form of fat in a hump on their back, they have long lashes to protect their eyes from sand being blown, and they have wide feet so they don't sink into the sand as they're walking across the desert.

So these organisms, the cacti, which is a type of plant, and the camel, which is a type of animal, have specialised features or adaptations that allow them to survive and thrive within their particular habitat, in this case, the desert.

Looking at other examples, both the lily pad and the fish live in cooler, watery habitats, but they also have different adaptations from each other.

So the lily pad has a large leaf with a very large surface area so it can float on the top of the surface to maximise photosynthesis, whereas the fish has gills, which allows it to breathe the little amount of oxygen stored in the water and fins that allow it to swim efficiently through the water.

So they also have specialist adaptations for their environment.

Now, many species are so highly adapted to their habitat that they cannot live anywhere else.

So take the fish for example.

The gills that they have means that they can only survive underwater.

They can't breathe air, and if they are out of the water for any length of time, they are likely to die.

They cannot survive outside of water for very long at all because they do not have the right adaptations in order to do so.

And if those conditions of the habitat change, then the species may be less well adapted to live and thrive in those new changed conditions, and as a result may be in danger of dying out.

So changes to the environment, changes to the habitat that organisms are living within has serious consequences for their ability to survive.

So true or false? Species are not affected when conditions in a habitat change.

Okay, so you should have said that that is false, but why? So you should have explained that by saying that when conditions in a habitat change, species may be less well adapted to live and thrive there and could be in danger of dying out.

Well done if you said that.

Now, lots of evidence has been collected across many, many years by a number of global scientific agencies, and this data, when it has been analysed and collated, confirms that climate change and global warming are occurring on Earth.

So if we look at the data in the graph there, what does it show? We've got years from 1880 up to the present day along the x-axis across the bottom, and on the y-axis on the left, we have the temperature difference in degrees centigrade when it is compared to what the global mean was between 1951 and 1980.

So the global mean is zero and the temperature difference is plotted as the line on the graph.

And the four different coloured lines show data that has been collected from four different agencies, NASA, the Met Office, the National Climatic Data Centre, and the Japanese Meteorological Agency.

So what does this graph show? Well, you can see by looking at it that there is firstly strong agreement between those four agencies in the data that they have collected.

They are all showing a similar pattern and similar changes in the pattern, and in some places the data completely overlaps and you can't see the four different lines because they are in such strong agreement.

We can also see how there are year-to-year fluctuations in the global temperature.

The graph is going up and down across the whole of the graph.

We can also see, however, that there is a general trend in an increase in temperature, where it started at its lowest just after 1900, about 1910, and has been more or less on an increase ever since then to the present day.

So over the last 100 years or so, there has been an average surface temperature increase as a general trend.

So what does the graph show about the average surface temperature of Earth? Does it show that, A, the trend is an increase over the last 100 years; or B, the temperature rises every year compared to the previous year; or C, there is a lot of disagreement between the four scientific agencies who collected the data? I'll give you five seconds to decide.

Okay, so you should have said that the graph shows the trend is an increase over the last 100 years.

Well done if you chose that.

So the global average temperature on Earth is increasing, but this does not mean that it's going to feel hotter everywhere, because what it's showing, this global surface temperature increase is showing global warming.

Global warming is the additional increase in surface temperature on the Earth caused by extra greenhouse gases in the atmosphere.

And global warming disrupts the weather patterns across Earth, leading to climate change.

So climate change is the disruption to long-term weather patterns.

And as global warming continues, so climate change will continue, and climate change brings more extreme weather events.

They become more frequent and more extreme.

So not everywhere will feel hotter.

Some places will.

Some places will experience extreme temperatures which will lead to more heat waves, which will cause drought and wildfires, and in fact, we are already seeing this increasing in frequency.

There have been a number of wildfires which are larger and more serious than they've ever been before occurring in many places across the world.

So some places will experience extreme heat, but other places will experience extreme rainfall and high winds, and more severe storms will lead to heavy rainfall which will cause flooding.

Humans and all animals depend on plants for food, and that's because animals are consumers.

We cannot make our own food.

We rely on other organisms that make their own food that we can then go on to eat.

And plants are producers, they make their own food.

And so humans and all animals are dependent on plants for food, whether they eat them directly or whether they eat other animals that have eaten plants instead.

Now, climate change will make it harder to grow enough crops for food, and we grow crops so that we can feed animals that we then go on to eat and so that we can feed ourselves.

So extreme heat will cause heatwaves and drought, and plants and crops which are not adapted to cope with those extreme conditions will not be able to survive and that will lead to the death of those plants.

Elsewhere, storms will cause rivers and lakes to flood, and this will ruin crops which are not adapted to survive in waterlogged soils.

And coastal flooding caused by rising sea levels will kill crops that are not adapted to survive in high salt concentrations, because the sea is salty, but water on land is not.

So these changes in climate will make it very hard for plants to survive and thrive because they will not be adapted to the new and changed conditions.

So which of these extreme weather events become more common as climate change continues, droughts, floods, heatwaves, or storms? I'll give you five seconds to decide.

Okay, so you should have said that all of these extreme weather events will become more common as climate change continues.

Well done if you did.

So let's review that part of the lesson by considering wheat.

Now, wheat is a crop produced by farming and it is used in many different food products, such as flour, bread, and pasta.

And it's a staple food because it forms a main ingredient in so many of these basic key ingredients.

3.

2 billion people, that's 40% of the world's population, depend on wheat because it is a staple food, and wheat is adapted to grow best within a fairly narrow range of conditions.

So what I would like you to do is to explain how climate change could affect the production of wheat.

So pause the video and come back to me when you're ready.

Okay, let's review your work.

So how will climate change affect the production of wheat? Well, you might have said that wheat has adaptations that allow it to grow best within a narrow range of conditions.

And the average surface temperature of Earth is increasing.

This is called global warming.

And extreme weather events are becoming more common.

This is called climate change.

And wheat may be less well adapted to grow in the warmer temperatures, in extreme heat, or in extreme flooding.

So wheat may be damaged or killed by extreme weather events such as heatwaves, droughts, storms, and floods.

Well done if you've got all of those points.

Okay, let's move on to climate change and biodiversity.

So we've thought about how climate change is affecting crop plants and therefore the food that we can eat, but climate change won't be restricted to just affecting crops that we grow.

It will also affect many different species.

Biodiversity is the range of species that are living in a habitat.

So forest land, for instance, has a high biodiversity because there are many different organisms living within it, and all of those living organisms are interdependent.

That means that they all rely upon each other for their survival.

Sometimes that's direct, for instance, one animal eating another animal, or one animal using a tree as a nesting site, for instance.

And other times it's a less direct route.

Maybe a bird eats an insect which has eaten leaves off of a tree, and so the bird is dependent on the tree because it is dependent on the insect which is eating the tree.

So there is great interdependency between all of the organisms living within the habitat.

And if it is a very rich habitat with a great number of species living within it, then biodiversity is high.

Now, if one species dies out, this could lead to the death of many other species because of this interdependency.

So if the tree dies out within a forest, not only will the insects die out, but the birds of which eat the insects will also be at risk as well.

And climate change causes the loss of biodiversity and therefore threatens the survival of many different species.

So who gives the correct definition of biodiversity? Andeep says, "Biodiversity is the way species depend on each other, such as through food chains." Izzy says, "Biodiversity is the loss of species from a habitat when conditions change." And Laura says, "Biodiversity is the range of species living in a habitat," but who has the correct definition? I'll give you five seconds to decide.

Okay, so you should have said that Laura gives the correct definition of biodiversity.

Well done if you chose her.

So we can consider biodiversity and climate change in a little bit more detail.

Let's consider a pond.

If the pond dried up, the frog would struggle because the water would have gone and the lilies will struggle because the water has gone, and so both of them will struggle to survive.

Climate change could cause long-term changes to the conditions of a habitat because climate change is affecting weather patterns.

And what that will ultimately mean is that some species can no longer live where they currently are because their habitat will have changed so significantly, as we've seen with the frog and the lily plants.

Now, in order for these species to continue to survive, they must either migrate, that means moving to a new habitat where the conditions are suitable for their adaptations, or they must adapt, and this means acquiring new adaptations that will enable them to survive within the new conditions in the new habitat.

However, adaptation doesn't just happen overnight and it doesn't happen by conscious thought either.

It takes many generations for adaptations to change through a process called evolution.

So evolution is this process of gradual change of adaptations in a species.

So what I'd like you to do is to complete the sentences to describe how species can survive long-term changes in the conditions of their habitat, choosing only from the words evolution and migration.

So can you get them in the right places? And I'll give you five seconds to decide where they go.

Okay, so let's check what you put.

Species can move to a new habitat where the conditions are right for them.

This is called migration.

Species can acquire helpful new adaptations over generations.

This is called evolution.

Did you get them round the right way? Well done if you did.

Across the world, most of the countries have come together in an organisation called the United Nations, and they formed a specialist scientific panel called the Intergovernmental Panel on Climate Change, the IPCC.

And this group of specialist scientists reported in 2023 that half of the 4,000 species that they had studied had migrated to new habitat because of climate change.

So in Europe, butterfly populations have been seen to have migrated up to 200 kilometres further north in response to rising temperatures because it is now much warmer further north than it has ever been before, and so these butterflies are able to survive and thrive in places far north of where they have ever normally been found.

And this is one example of the 2,000 or so species that the IPCC have observed that have migrated to new habitats because of climate change.

But migration is not always possible for all organisms. So frogs, for instance, and other amphibians may find it very difficult to find suitable habitat within 50 kilometres of their existing habitat.

Now, 50 kilometres is far to walk or hop for a frog, so trying to go any further would be very difficult indeed.

And this means that if they cannot find new places to live and their existing places has changed or even gone, then where are they supposed to live and how can they survive? This issue of migration is made worse by human activities and choices that we are making.

So we often destroy habitat because we are turning land from one form into agriculture, for instance, or building factories and industry onto it or building roadways and other transport systems or building towns and housing developments, and all of these different human activities and choices that we are making destroy habitat and make it very difficult for organisms to migrate to different locations in response to climate change.

Now, climate change is getting faster.

It's happening faster each year and faster than many species can evolve to adapt.

So evolution occurs over many generations, and for many species which reproduce maybe only once a year or even longer than that, this process can take many, many years indeed.

Evolution isn't a planned or a conscious decision-making event.

It happens by random chance.

New adaptations randomly appear, and they may not be helpful for the conditions if those conditions have changed, and they might not happen fast enough if conditions are changing very quickly and the species is reproducing very slowly.

So if we take the giant panda, for instance, these animals are now endangered because climate change is reducing the availability of their main food source, which is bamboo.

And because they reproduce slowly and are therefore able to evolve very, very slowly, they cannot adapt fast enough to the removal of their habitat in order to find a new food source, and so they are now endangered.

Now, this is a very bleak picture that I've painted so far, but there is hope.

There are plenty of things that we can do to make this situation better.

Many of the human activities that cause greenhouse gas emissions contribute to climate change, but if we change our behaviour to reduce greenhouse gas emissions, we will be able to limit climate change.

So if we stop driving petrol cars, if we walk instead of driving, if we use green electricity, if we heat our homes less, if we eat less beef, if we recycle and reuse instead of just throwing things away.

If we do all of these things and many, many more things besides, we will be able to limit our impact on climate change and therefore reduce the impact that climate change will have on biodiversity.

But it will require us all doing something, us all committing to make these changes, and us all working together across the whole planet in order to slow climate change and protect biodiversity.

And protecting biodiversity isn't just good for the animals and plants and other organisms that survive because of it, but it's also really important for our health, wellbeing, and survival as well.

So who is correct? Lucas says, "It can take many years for species to evolve helpful new adaptations to climate change." Alex says, "When conditions in their habitat change, species can decide to evolve helpful adaptations." And Sofia says, "Species can't plan their evolution.

It just happens at random," but who is correct? I'll give you five seconds to decide.

Okay, you should have said that Lucas and Sofia are both correct.

Well done if you did.

Okay, let's conclude our lesson today by looking at polar bears.

So polar bears are highly adapted animals and they hunt for seals.

Now, they use sea ice as a platform from which to hunt, because they can spot the seals in the water from the sea ice and then use the sea ice as a diving platform to go and hunt and catch the seals.

So sea ice is a really important feature that they have become adapted to use.

But climate change is causing sea ice to melt, and you can see how broken up it is in the picture on the screen there.

So what I would like you to do is to explain why climate change causing sea ice to melt might put polar bears in danger of dying out.

So pause the video and come back to me when you're ready.

Okay, let's review your work.

So climate change causing sea ice to melt might put polar bears in danger of dying out because without sea ice, polar bears may not be able to hunt for seals, so they may not catch enough food to survive.

And polar bears could migrate, but they may not be able to find another suitable habitat.

If they cannot migrate, adaptation is another alternative, but polar bears may not be able to evolve quickly enough to adapt to the changing climate.

Did you include all of those points? Well done if you did, and do add to your work if you need to.

Good job.

Okay, we've come to the end of our lesson, and we have seen that species have adaptations that enable them to live and thrive in the conditions in their habitat.

Human emissions of greenhouse gases are leading to global warming and causing climate change.

And climate change is changing the conditions in habitats, so species may be less well adapted to live there.

Climate change includes more frequent extreme weather events and can lead to biodiversity loss.

And some, but not all species can survive changes in conditions by migrating to a new habitat, or they may be able to acquire new adaptations through evolution, but often this happens far too slowly for it to be useful to them.

So I hope that's given you lots of things to think about and lots of reasons to make changes to help reduce climate change and protect biodiversity.

So thank you very much for joining me today, and I hope to see you again soon.

Bye!.