Lesson video

Hello, my name is Mr. March, and I'm here today to teach you all about the plant and animal adaptations in cold environments.

So grab everything that you need for today's lesson and let's get going.

So by the end of today's lesson, you'll be able to explain how plants and animals are well adapted to the physical conditions in cold environments, and that there are issues related to biodiversity.

There are four key terms for today's lesson, and those are: adaptation, hibernation, biodiversity, and ecosystem.

Adaptation refers to the evolutionary changes that improve an organism's chance of survival in its environment.

Hibernation refers to a state that certain animals enter to save energy during periods of unfavourable weather conditions or food shortages.

Biodiversity refers to the variety of different types of life found in a particular area, and ecosystem refers to a community of living organisms and their interactions with their environment.

There are three learning cycles for today's lesson, and we're going to start with the first learning cycle, which is, how have animals adapted to cold environments? Now, cold environments have extreme conditions that most plants and animals are unable to survive in.

However, cold environments are home to a variety of plants and animals.

It would be a mistake to say that no life exists there.

This is because plants and animals have evolved adaptations to cope with those cold environment conditions.

An adaptation is an evolutionary change that improves an organism's chance of survival in its environment.

These are adaptations and evolutionary changes which have taken millions of years.

Now, animal adaptations in cold environments include the following: thermoregulation, being able to control one's body heat; hibernation; burrowing; migration; and camouflage.

These are five adaptations which we are going to look at individually in a moment of animals in cold environments about how they've adapted to those severe cold environment conditions.

Now, thermoregulation is about limiting the amount of heat loss through different adaptations which have evolved over millions of years.

And the first of these are small, rounded ears, as we can actually see in the image in front of you, of the polar bear, and the short snouts, as again seen by the second image with the Arctic fox.

And this is to reduce the amount of surface area that heat can be lost from.

The next is the thick layer of fur or fat that can be used to insulate the body and keep that heat in.

In fact, that thick layer of fat can also be used as a energy source during those lean cold winter months when the food is very much scarce.

Tails, they're either very short to reduce heat loss, or as we can see with the example of the Arctic fox here, very thick and bushy to wrap around the animal when the animal is trying to sleep and to stay warm.

The second adaptation we need to know about is hibernation.

And hibernation is a state some species perform by slowing their heart rate, metabolism, and breathing to save energy.

Remember, cold environments, the conditions are very extreme, extremely cold, extremely dry, and food is very scarce.

So being able to save energy in this way could be a life saver.

Now again, it is actually a misconception that most animals hibernate during these cold winter months.

In fact, only a few species enter full hibernation for an extended period of weeks or months.

One is the grizzly bear that you can see in front of you, and the other is the ground Arctic squirrel, also on the image in front of you.

But the vast, vast majority do not enter full hibernation.

Some other species have a partial hibernation, and this is called a torpor.

And this lasts a short period of hours or days.

Since the conditions are so cold, they need to remain active to stay warm, but also remember, animals in cold environments have adapted to be able to deal with those cold environment conditions.

Therefore, there isn't such a need to be able to hibernate.

Our next adaptation is again a behavioural adaptation, and this is burrowing.

And burrowing involves digging into the snow and soil, which then insulates the animal.

It has other benefits as well.

First, it protects those species from both the cold and those cold winds that we find in cold environments.

It also provides safety from predators.

Now, one species that does burrow is a lemming, as you can see on the screen in front of you.

It lives in tunnel systems which provide both warmth and protection from predators like owls and foxes.

Our next adaptation is, again, behavioural.

It is migration.

And migration is when animals live in cold environments in spring and summer, but move to lower latitudes in winter where they're looking for more warmth.

Now, in the Arctic tundra, caribou or reindeer move south in winter when the deep snow covers their food source, that grass, lichens, and plants, and therefore they move further south to continue to find that food source where there isn't that snow cover where it is much, much warmer during those winter months.

So migration means animals do not need that thermoregulation, for example, that thick layer of fat or that hibernation adaptation simply because they move away from that cold area for those months.

Camouflage also helps animals blend into their environment, making them less visible to predators or prey.

In cold environments, fur, feathers may change colour with the seasons.

For example, the Arctic fox, which is pictured in the bottom right of the screen, and the snowshoe hare pictured in the top right, both have white fur to blend into the snow during the winter.

It then changes into a brown fur during the summer to match the tundra landscape, thereby being able to avoid predators, or being able to hunt their prey much more successfully by being covered and camouflaged in their environment.

So a quick learning check.

Which three of the following are adaptations of cold environment animals? So please pause the video here whilst you consider and then select your three answers.

Good luck.

And the answers were, we have thermoregulation, hibernation, and burrowing as the three adaptations.

Really, really well done if you were able to identify those answers.

And another learning check.

True or false? All animal species in cold environments have to hibernate fully to survive the extreme winter cold climate.

Again, pause the video here whilst you consider and then select your answer.

And the correct answer was false.

Now, once again, I would like you to pause the video whilst you consider your answer as to why this statement is false.

And the reason it is false is that while it is true that a few species enter full hibernation, others reduce their energy use with torpor, which is that light hibernation.

Also, many more are adapted to actually survive through thermoregulation adaptations and by burrowing.

Species may also just migrate to areas with a warmer winter climate.

As a result, it is untrue to say that all animals in the cold environments hibernate fully to survive those extreme winter cold climate.

So really, really well done if you were able to identify those two correct answers.

So Arctic foxes, for example, have several adaptations for cold environments.

And let's have a look at some of those.

Arctic foxes are adapted to be able to tolerate those cold temperatures which can drop as low as minus 50 degrees Celsius.

They have thick, dense fur to retain that body heat.

They have thick paw pads to prevent heat loss and sinking into the snow.

They have a fluffy tail which they can use to wrap around them whilst they're sleeping, again to keep that warmth.

Their fur that changes from white in winter to grey in summer is great for camouflage and enables more successful hunting.

They have small surface area ears and a small snout to limit that heat loss.

And finally, underneath that fur, they have black skin, which is able to absorb more heat from the sunlight.

So two practise questions now.

I would like you to match the sentence beginning on the left to the correct sentence ending on the right.

And the second practise question asks you to explain two adaptations that enable Arctic foxes to survive in its cold environment.

And I've given you two images of an Arctic fox in the winter and an Arctic fox in the summer to really help and guide you in your answer.

This question then is asking you to identify two adaptations and then explain how each adaptation helps the Arctic fox to survive in its cold environment.

So pause the video here whilst you attempt those two practise questions.

Best of luck.

And the answers are: so matching the sentence beginning to the correct sentence ending, this is what you should have come up with.

It says, not all animals hibernate in winter because some are adapted to stay warm while others simply migrate.

Animals that burrow can avoid the cold temperatures, strong winds, and potential predators.

And adaptation is a change in structure or function that improves an organism's chance of survival in its environment.

Many cold environment animals have small ears to reduce surface area, thereby reducing heat loss.

An Arctic fox changes colour with the seasons to allow it to blend into the environment to hunt successfully.

And the second question asks you to explain two adaptations that enable Arctic foxes to survive in its cold environment.

Now, your answers may have included two of the following.

It says that temperatures in the Arctic winter can drop as low as minus 50 degrees Celsius.

Arctic foxes have thick, dense fur that enables them to retain their body temperature in the extremely cold conditions.

The ground is often covered with snow during the Arctic winters, and Arctic foxes are a brown colour in summer, which would stand out against the snow and make it harder for them to catch their prey in winter.

Therefore, they have adapted to have their fur change colour with the seasons, brown during the summer and white during the winter.

And also you may have said that heat is lost quickly from large surface areas.

So Arctic foxes have adapted very small ears and a short snout to reduce their surface area, which helps them to retain their body heat.

Also, deep snow is difficult to move through, and this makes it harder for animals like foxes to catch their prey.

It also wastes energy on movement.

As a result, Arctic foxes have thick pads on their paws that stop them sinking into the snow and allows them to move quickly and efficiently across those snowy surfaces.

So really, really well done if you were able to include any of those answers in your own answer.

And let's move on.

So we're on now to our second learning cycle, which is, how have plants adapted to cold environments? Cold environments like the polar and tundra biomes have much lower levels of biodiversity than other global biomes, and this is due to a range of different challenges found specifically in those areas.

Let's take a look at those now.

So we have a short growing season in the polar and tundra biome.

There are incredibly strong cold winds in this area.

There is a lack of precipitation.

For example, in polar biome there is often less than 250 millimetres.

In fact, it's actually defined as a cold desert due to the lack of rainfall and its cold temperatures.

Again, yes, it has extreme cold temperatures there.

There's permafrost, which means that the soil is frozen for a large period of time, if not the entire year.

There's a slow and limited nutrient cycle, which means there's very few nutrients for any plants to absorb.

And finally, the waterlogged soils in the tundra.

As those soils thaw and melt, it can release that water, which ends up causing the soils to become waterlogged, which very, very difficult for plant growth.

So a quick learning check.

I would like you to identify the three missing challenges which I just previously mentioned to biodiversity in cold environments.

So pause the video here whilst you try to remember and identify those three remaining challenges.

Best of luck.

And the correct answers were: strong winds, lack of precipitation, and finally, permafrost or frozen soils.

So while the surface layer of soil melts during the summer in tundra biomes, the lower layer still remain frozen, and this is a massive contributor to the lower amount of biodiversity in cold environments.

How does this work though? Well, the lower soil layers are frozen all year round, and this means that plant roots are unable to penetrate and absorb those nutrients from deep into the ground.

Plant roots then must develop a wide but shallow root system to anchor the plant into the soil against those strong winds which we find in cold environments.

These conditions though limit the amount of growth, so therefore only small plants and shrubs can actually grow in this environment.

So very few plants can actually live in the polar biome.

But in the tundra biome, we do see more biodiversity, and this has basically been enabled through different adaptations to meet those different challenges we mentioned just a while ago.

For example, one challenge we know is of frozen soils, of permafrost, and lichen has managed to deal or adapt to this challenge because it doesn't need soil to actually grow.

It grows very slowly, it can withstand very cold temperatures and it can even survive beneath snow, which is of course very important where precipitation such as snowfall may end up covering it.

So this is how lichen has managed to deal with those frozen soils.

Meanwhile, another challenge is extreme cold.

The Arctic poppy has managed to adapt to this challenge with a very hairy stem to retain the heat, its own heat.

And in fact, the flower can track or follow the Sun to maximise the amount of sunlight it receives to increase photosynthesis and thereby improve its chances of survival.

Further challenges are those strong winds, and cotton grass is low-lying to protect it from those strong winds.

And on top of this, it has small seeds which are dispersed easily by those strong winds and has thin leaves to reduce water loss by transpiration.

So it grows and produces seeds very quickly, which are able to be spread by the wind over a large area.

And it takes advantage of the short growing season that we find in the tundra.

We also see a challenge of a lack of nutrients.

Well, cushion plant, as we can see in the image in front of you, is compact and low so it helps it to survive against those cold and windy conditions, and it doesn't really even need to absorb nutrients from the soil because these plants trap airborne dust and use it as a source of nutrients.

Since tundra soil is so low in nutrients, this adaptation allows it to survive and even thrive.

So a quick learning check.

And the question is, why do Arctic poppy flowers track the Sun? You have three options to read through there.

What I'd like you to do is pause the video, read through the options, and then select your answer.

Best of luck.

And the correct answer is to increase photosynthesis.

Really, really well done if you were able to identify that correct answer.

And our next learning check is, which three of the following are ways in which cotton grass has adapted to the tundra conditions? So once again, I'd like you to read through the four options, pause the video, and then select your three answers.

Best of luck.

And the correct answers are A, which is that it is low-lying to shelter from strong winds.

It has adapted small seeds to be dispersed or spread easily by the wind over a large area.

And finally, it has fast-growing seeds to take advantage of the very short growing season that is found there.

So really, really well done if you were able to identify those three correct answers.

We're on now to our two practise questions.

And the first one is that tundra is a Finnish word meaning treeless area.

It says to complete the paragraph below, explaining why tundra soils cause this treeless landscape using the words shown below to fill in the gaps.

The second question shows two photos of tundra plants and it asks you to identify one adaptation for each and explain how these help plants to survive in its cold environment.

So what I'd like you to do right now is pause the video whilst you attempt these two practise questions.

Best of luck.

And now some feedback for question one.

And these are the answers which you should have come up with.

It says, in the tundra, plants face many challenges that limits biodiversity.

One challenge is permanently frozen soils, known as permafrost, which mean plants are unable to send long roots deep into the soil.

This means plant root systems must be wide and shallow to anchor themselves against the strong polar winds.

Only being able to access nutrients in the soil's top layer, which is only a few centimetres deep, is a key reason as to why trees rarely grow in the tundra.

And for the second question, these are some of the answers which you may have included.

It says, photo A shows lichen which has adapted to the lack of soil in polar and tundra environments by being able to grow without soil.

It can even survive buried underneath snow.

Photo B shows an Arctic poppy which can track the movement of the Sun to maximise photosynthesis.

This is a big advantage for survival in an environment where the amount of sunlight is limited.

So really, really well done if you were able to include any of those answers in your own.

We're on now to our third and final learning cycle, which is, what threatens cold environment biodiversity? Now, we already know that biodiversity is low in cold environments because of the extreme conditions.

These are the limited precipitation that's found there, often less than 250 millimetres per year.

Those extreme cold temperatures during the daytime and the even colder temperatures during the night.

Those strong polar winds.

Poor soil quality, as in the lack of nutrients and that the soil is often very thin due to permafrost.

And the short growing season as well.

Only specially-adapted plants and animals are able to survive these very, very extreme conditions.

Plants and animals that are highly adapted to an ecosystem struggle to cope with any changes to that ecosystem.

And this makes the cold environment ecosystem extremely fragile and easily damaged.

Fragile ecosystems are therefore very vulnerable to any human activity.

So a quick learning check.

Which of the following help explain low biodiversity in cold environments? Select all that apply.

So pause the video here, consider, and then select your answer.

Best of luck.

And the correct answers were, so it was A, the arid conditions, you know, the lack of precipitation, less than 250 millimetres per year.

It was also the low level of nutrients, and finally, it was the extremely low or cold temperatures.

Really, really well done if you were able to identify those three correct answers.

So what is threatening the biodiversity of cold environments? Well, unfortunately it all comes back to human activity, and the first of which is mineral extraction.

Drilling and then transporting oil and gas disrupts those fragile habitats, with the possibility of deadly oil spills, which is certainly going to limit and reduce the amount of biodiversity found there.

Also, we see increasing pollution.

Plastic pollution often accumulates in Arctic and Antarctic waters, which harms marine life, which can get trapped or even swallow that plastic.

We are also seeing increasing shipping traffic in the Arctic and the Antarctic, and tourism is increasing pollution and disrupting sensitive wildlife found there.

We're also seeing overfishing on a larger and larger scale.

Commercial overfishing is reducing key species like krill, which is a food source for a variety of different species in the cold environment food web, such as whales, seals, and penguins.

So it's going to have a much larger knock-on effect to the food web as a whole.

Finally, we have climate change, and climate change is causing sea ice to melt and that is destroying habitats, for example, for polar bears.

Warmer climates are also allowing invasive species to migrate further into cold environments, and this is causing greater competition between those species, which is inevitably leading to some animals dying out and becoming extinct as a result.

Permafrost thaw is also affecting tundra species since it's creating a more waterlogged soil, and species which are adapted for cold environments are unable to adapt to these new conditions.

All of these four reasons are causing a drop or a decrease in the biodiversity found in cold environments.

What we can see here is that due to climate change, the Arctic has warmed nearly four times faster than the global average.

So the cold environments that we're looking at are being affected much more than other areas around the globe.

And this is causing changes to polar ecosystems, which are different from that which polar plant and animal species are actually adapted to.

And a term for this is ecosystem stress.

And if we just spend a little bit of time looking at the diagrams or pictures in front of you, you can see just how much the Arctic ice is slowly shrinking over time.

Compare 1982's ice extent at the North Pole to 2007, you can see a huge decrease.

But fast forward perhaps to 2070 to 2090 in the bottom right and you can see just how much they predict, the scientists predict, the Arctic sea ice extent to have decreased.

And all of this is going to affect the species found in these areas.

Time now for a learning check.

True or false? Climate change has no effect on biodiversity in cold environments.

So please pause the video here whilst you consider, and then select your answer.

And the correct answer is false.

Now, once again, what I'd like you to do is pause the video whilst you consider as to why this statement is false.

And the reason it is false is because global warming is leading to cold environments becoming warmer, leading to the melting of sea ice and permafrost.

Now, warmer polar environments allows invasive species to migrate into these habitats to compete with those native species.

This all subsequently leads to habitat and species loss, leading to a decrease in the biodiversity of some cold environment ecosystems. So really, really well done if you were able to identify those two correct answers.

We're on now to our two practise questions, and the first one asks you to categorise the statements below into physical causes, by which I mean natural causes, of low biodiversity, and the human threats to biodiversity in cold environments.

And the second practise question asks you then to explain two ways in which human activity threatens biodiversity in cold environments.

In your answer, I'm really looking for you to state the human activity which is threatening biodiversity, and then go one step further to explain how this factor threatens biodiversity.

So please now pause the video whilst you attempt these two questions.

Best of luck.

And now some feedback.

So you were asked to categorise the below statements into physical causes or human threats to biodiversity in cold environments.

The first one is an extreme climate, you know, very cold daytime temperatures and even colder nighttime temperatures.

Well, this is a physical cause.

It is a natural cause.

Pollution of cold environments.

This is unfortunately a human threat to biodiversity.

Poor soil quality due to limited nutrients.

Well, this is a physical cause.

It is a natural cause.

Likewise, limited precipitation is also a physical cause.

Now, climate change, which is causing sea ice to melt and habitat loss is a human threat.

This is a human-caused threat to biodiversity.

Likewise, the overfishing of key ecosystem species, such as krill, is a human threat.

Finally, the strong polar winds we find there is a physical cause.

Now the second question asks you to explain two ways which human activity threatens biodiversity in cold environments.

And your answer could have included any two of the following, first of which is climate change.

It says warmer temperatures cause sea ice and permafrost to melt.

This is causing habitat loss while also allowing invasive species to migrate into this environment, thereby competing with indigenous or native species.

Overfishing.

Commercial overfishing means catching marine species at a rate faster than they can reproduce, leading to population decline.

It also disrupts food webs, with overfishing of krill, for example, having knock-on effects to the numbers of whales and seals that rely on it.

Pollution.

There is an accumulation of pollution and plastic and other waste which is harming marine life, while increased shipping is increasing pollution and the risk of destructive oil spills.

Finally, mineral extraction.

The extraction and transportation of oil and coal and other minerals disrupt species and can fragment and destroy habitats found there.

So really, really well done if you were able to include any of those in your own answer.

On now to our summary.

And these are the key learning points from today's lesson.

An adaptation is an evolutionary change that improves an organism's chance of survival in its environment.

Some animals and plants have evolved adaptations that allow them to live in the extreme conditions of the cold environments.

Although a range of animals and plants have adapted to live in cold environment ecosystems, the extreme conditions means that biodiversity is low compared to that of other large scale ecosystems or biomes.

Human activities such as climate change are putting increased pressure on cold environments, leading to biodiversity loss.

So really, really well done during today's lesson.

It was a pleasure to teach you, and I will see you again on the next lesson.

Goodbye.