Unit A Lesson A6 Ecosystem Cycles
Completion requirements
Lesson A6: Ecosystem Cycles
Video Lesson
Watch this video to learn more about how various types of matter cycle through ecosystems.
Lesson A6: Ecosystem Cycles
Cycles Connect Living Organisms with Their Non-living Environments
Energy flows through an ecosystem in one direction -- from plants to consumers to decomposers. We can learn much about an ecosystem by following the energy trail. Organisms are not made of energy, however. How do organisms obtain the substances they need to grow? Our bodies and those of other organisms consist of water, carbon, and other substances. We are about 65% water and 19% carbon.
As long as the Sun radiates energy, ecosystems have a constantly renewed energy supply. However, Earth has a limited amount of water, carbon, and other substances. Fortunately, living and non-living processes recycle all the materials needed for life. If ecosystems did not recycle substances, life on Earth would stop. The planet would be depleted of the building materials organisms need to live and grow.
Energy flows through an ecosystem in one direction -- from plants to consumers to decomposers. We can learn much about an ecosystem by following the energy trail. Organisms are not made of energy, however. How do organisms obtain the substances they need to grow? Our bodies and those of other organisms consist of water, carbon, and other substances. We are about 65% water and 19% carbon.
As long as the Sun radiates energy, ecosystems have a constantly renewed energy supply. However, Earth has a limited amount of water, carbon, and other substances. Fortunately, living and non-living processes recycle all the materials needed for life. If ecosystems did not recycle substances, life on Earth would stop. The planet would be depleted of the building materials organisms need to live and grow.
Reading and Materials for This Lesson
Science in Action 7
Materials:
Science in Action 7
Reading: Pages 44–46
Materials:
No other materials are needed for this lesson.
Figure A.2.6.1 – Plants need water to live. Where does the water come from? Where does it go?
Figure A.2.6.2 – This snail’s hard shell contains carbon. What is the source of the carbon?
Figure A.2.6.3 – Carbon cycles between plants, animals, and the atmosphere.
Figure A.2.6.4 – Follow the molecules of each substance to see its role in the carbon cycle.
Carbon: It is Going Places!
Carbon is everywhere on Earth. It is in every living organism, and it is in the air, rocks, and oceans. It is also on the move. You can think of the carbon cycle as having two parts. Both parts operate at the same time all the time.
Carbon cycles through living organisms using three processes: photosynthesis, respiration, and eating of plants.
A blackberry bush uses carbon dioxide in the air to perform photosynthesis. It releases oxygen. Black bears love to eat wild blackberries. A black bear absorbs carbon in the blackberries in the form of carbohydrates. As it breathes, its body absorbs oxygen and releases carbon dioxide into the air.
Plants and animals depend on each other. Plants provide animals with the oxygen they need, and animals help provide plants with the carbon dioxide they need.
Carbon cycles globally, also. Earth contains reservoirs of carbon in the atmosphere, oceans, soil, and rock. A reservoir is a holding place, and Earth has many holding places for carbon. Various physical (non-living) processes cycle carbon among these reservoirs. This cycle is very slow. Carbon stored in rock or on the ocean floor may stay there for millions of years.
Remember the black bear eating blackberries? Carbon in the black bear’s body enters this global cycle eventually when the bear dies. It’s body, similar to ours, is about 19% carbon. As it decomposes, it releases carbon dioxide into the air. Carbon also enters the soil. In millions of years, that carbon could be in the ocean, in limestone rock, or in an oil deposit deep underground. Even in rock, carbon does not sit around doing nothing forever! Slow physical processes ensure that the carbon is sent on its way once again. Carbon is a world traveller!
Carbon is everywhere on Earth. It is in every living organism, and it is in the air, rocks, and oceans. It is also on the move. You can think of the carbon cycle as having two parts. Both parts operate at the same time all the time.
Carbon cycles through living organisms using three processes: photosynthesis, respiration, and eating of plants.
A blackberry bush uses carbon dioxide in the air to perform photosynthesis. It releases oxygen. Black bears love to eat wild blackberries. A black bear absorbs carbon in the blackberries in the form of carbohydrates. As it breathes, its body absorbs oxygen and releases carbon dioxide into the air.
Plants and animals depend on each other. Plants provide animals with the oxygen they need, and animals help provide plants with the carbon dioxide they need.
Carbon cycles globally, also. Earth contains reservoirs of carbon in the atmosphere, oceans, soil, and rock. A reservoir is a holding place, and Earth has many holding places for carbon. Various physical (non-living) processes cycle carbon among these reservoirs. This cycle is very slow. Carbon stored in rock or on the ocean floor may stay there for millions of years.
Remember the black bear eating blackberries? Carbon in the black bear’s body enters this global cycle eventually when the bear dies. It’s body, similar to ours, is about 19% carbon. As it decomposes, it releases carbon dioxide into the air. Carbon also enters the soil. In millions of years, that carbon could be in the ocean, in limestone rock, or in an oil deposit deep underground. Even in rock, carbon does not sit around doing nothing forever! Slow physical processes ensure that the carbon is sent on its way once again. Carbon is a world traveller!
Figure A.2.6.5 – Carbon cycles among the atmosphere, the oceans, and the land.
Figure A.2.6.6 – Limestone cliffs at Athabasca Falls near Jasper, Alberta
Figure A.2.6.7 – Oil pumps bring carbon-rich oil from deep in Earth’s crust.
Think • Interpret • Decide
The Carbon Cycle
Carbon is everywhere, but sometimes it is in places that you wouldn't suspect. And you might think you know how it moves, but carbon has some tricks up its sleeve.
Try the following interactive diagram of the carbon cycle. Pay close attention to the arrows to observe how carbon moves through our world, and click all the buttons on the diagram to learn more about how carbon is stored and moves. When you have finished, answer the questions below.
CLICK HERE to launch the diagram in a new window.
Carbon is everywhere, but sometimes it is in places that you wouldn't suspect. And you might think you know how it moves, but carbon has some tricks up its sleeve.
Try the following interactive diagram of the carbon cycle. Pay close attention to the arrows to observe how carbon moves through our world, and click all the buttons on the diagram to learn more about how carbon is stored and moves. When you have finished, answer the questions below.
CLICK HERE to launch the diagram in a new window.
After you have finished the interactive adventure of carbon:
Think: What’s the point? Do you understand the various ways carbon moves through the world? If not, study the diagram some more.
Interpret: Where is the majority of carbon stored? How did it get there?
Decide: If burning fossil fuels increases the amount of carbon in the atmosphere, what are the long term consequences of this burning?
Carbon is very important to life on Earth, but it also causes concerns for global warming and the acidification of the oceans.
1,000,000,000 billion tonnes of Earth's carbon is stored in sediment and sedimentary rock. If you follow the arrows on the diagram carefully, you will see that carbon in sediments and sedimentary rock comes from carbon that was originally in the ocean, but settled to the bottom of the ocean as sediment, much of which later turns to sedimentary rock.
The carbon dioxide released by burning fossil fuels increases the amount of global warming, causing climate change. Over time, more carbon dioxide dissolves in ocean waters and makes the oceans more acidic.
Figure A.2.6.8 – An astronomer looks into the night sky. Is there life out there?
Figure A.2.6.9 – A black bear drinks water from a pond.
Water Equals Life
Astronomers have been looking for signs of life on other planets for many years. One thing they focus on is evidence of water. The reason they look for water is simple. Every living organism on Earth needs water. Likely, alien life needs water, too.
The Sun’s energy drives the water cycle on Earth. Water moves from rivers to the ocean, from the ocean to the atmosphere. Then, it falls to the ground as rain or snow to do it all over again.
The black bear is part of the water cycle. Now full of blackberries, he takes a refreshing drink of water. All animals need water to keep hydrated. The blackberries he ate were juicey. How does the blackberry plant get water into the berries? Similar to animals, plants need to take in water
Astronomers have been looking for signs of life on other planets for many years. One thing they focus on is evidence of water. The reason they look for water is simple. Every living organism on Earth needs water. Likely, alien life needs water, too.
The Sun’s energy drives the water cycle on Earth. Water moves from rivers to the ocean, from the ocean to the atmosphere. Then, it falls to the ground as rain or snow to do it all over again.
The black bear is part of the water cycle. Now full of blackberries, he takes a refreshing drink of water. All animals need water to keep hydrated. The blackberries he ate were juicey. How does the blackberry plant get water into the berries? Similar to animals, plants need to take in water
Figure A.2.6.10 – Water, similar to carbon, cycles between living organisms and non-living parts of Earth.
Plants absorb water through their roots. Rainwater soaks into the soil. The roots can absorb it. Special tissues in the plant transport water into the leaves and fruit. Water exits organisms, too. Bears, similar to all animals, urinate. Plants transpire,
which means they lose water through their leaves. This is why forests feel moist and cool.
Water is in three forms on Earth, but it occurs in many places. Water is always changing form from liquid rain to solid ice to gaseous steam. It is always moving from one place to another.
Water is in three forms on Earth, but it occurs in many places. Water is always changing form from liquid rain to solid ice to gaseous steam. It is always moving from one place to another.
Think • Interpret • Decide
The Water Cycle
The water cycle represents the movement of water through an amazing number of locations in, on, and above our planet. Water is very important for life, and it plays important roles in many other natural processes as well.
Try the following interactive diagram of the water cycle to learn more about how water moves on Earth. When you have finished, try answering the questions below.
CLICK HERE to launch the diagram in a new window.
The water cycle represents the movement of water through an amazing number of locations in, on, and above our planet. Water is very important for life, and it plays important roles in many other natural processes as well.
Try the following interactive diagram of the water cycle to learn more about how water moves on Earth. When you have finished, try answering the questions below.
CLICK HERE to launch the diagram in a new window.
After you have experienced the interactive Water Cycle adventure :
Think: What’s the point? Do you understand the various ways water moves through the world? If not, try it again.
Interpret: Who is the "main boss" of the water cycle? Why is it important that the "boss" causes water to move?
Decide: How could climate change affect the water cycle?
Pay particular attention to the different forms water in the water cycle... water is constantly changing from liquid to gas and back again.
The Sun is the main boss of the water cycle. Without the Sun's energy there would be no way for most parts of the water cycle to work. Water would not move, especially over, on, and across the land where it is so important for land plants and their ability
to live.
If Earth's climate gets warmer, more energy will be available to drive the water cycle. Ice melts, storms get stronger, and local climates change. If Earth's climate gets colder less energy is avilable for the water cycle. Water freezes and glaciers form.
This can result in an ice age.
Connections
Figure A.2.6.11 – Power plants like Genesee near Warburg, Alberta, are coal-fired power plants.
Figure A.2.6.12 – A large coal deposit is mined.
Connections: Industry
>> Carbon’s Long Journey
Alberta has a lot of coal underground. Almost half of Alberta’s electricity comes from burning coal that is mined in our province.
Coal is composed almost entirely of carbon. Coal is part of Earth’s carbon cycle. Did you know that coal was once living plants? Coal is very, very old. In fact, it is about 300 million years old. This period in Earth’s history is called the Carboniferous Period. Notice the word “carbon” in this word. Approximately 300 million years ago, coal’s carbon journey began
This period was long before the time of the dinosaurs. Not even flowering plants or trees were growing then. Many organisms in the Carboniferous Period, from plants to animals, were super-sized.
>> Carbon’s Long Journey
Alberta has a lot of coal underground. Almost half of Alberta’s electricity comes from burning coal that is mined in our province.
Coal is composed almost entirely of carbon. Coal is part of Earth’s carbon cycle. Did you know that coal was once living plants? Coal is very, very old. In fact, it is about 300 million years old. This period in Earth’s history is called the Carboniferous Period. Notice the word “carbon” in this word. Approximately 300 million years ago, coal’s carbon journey began
This period was long before the time of the dinosaurs. Not even flowering plants or trees were growing then. Many organisms in the Carboniferous Period, from plants to animals, were super-sized.
Forests of giant club mosses, giant horsetails, and tree ferns grew in vast warm humid swamps. Today, we find fossils of these even in coal.
Imagine a swampy forest of these plants! These plants live today, but they are sometimes called living fossils. They have changed little in 300 million years, but they are much smaller now. Coal formed from their distant relatives, which is why coal is called a fossil fuel.
Imagine a swampy forest of these plants! These plants live today, but they are sometimes called living fossils. They have changed little in 300 million years, but they are much smaller now. Coal formed from their distant relatives, which is why coal is called a fossil fuel.
Figure A.2.6.13 – Club moss grows in the forest.
Figure A.2.6.14 – A tree fern grows in New Zealand today.
Watch More
Carboniferous Forest Simulator
What would a walk through an ancient carboniferous forest be like? Watch this video that researchers are developing. It is a walk-through of an ancient swamp. It is not completed yet. The designers of this plan to put animals in next.
Insects, small reptiles, amphibians, and fish dominated this ancient food web. Giant dragonflies the size of seagulls were be flying overhead. Two-metre long centipedes were crawling over dead logs and leaves in the carboniferous swamps.
What would a walk through an ancient carboniferous forest be like? Watch this video that researchers are developing. It is a walk-through of an ancient swamp. It is not completed yet. The designers of this plan to put animals in next.
Insects, small reptiles, amphibians, and fish dominated this ancient food web. Giant dragonflies the size of seagulls were be flying overhead. Two-metre long centipedes were crawling over dead logs and leaves in the carboniferous swamps.
Figure A.2.6.15 – Horsetails grow on a sandy beach.
Figure A.2.6.16 – Millions of years of dying plant matter built up on ancient forest floors.
How Does an Ancient Ecosystem Turn Into Coal?
The process of making coal starts with photosynthesis. The giant forest plants performed photosynthesis just as modern plants do, but they were so large that they absorbed much more carbon dioxide than plants on Earth do today. What does photosynthesis do? Carbon dioxide is a molecule made of carbon and oxygen atoms. Plants take the carbon and make it into carbohydrates. (Notice the word carbon is in here, too.) They release the oxygen into the air. Three hundred million years ago, the air was richer in oxygen than it is today. It contained 35% oxygen instead of today’s 21%. More plant material and more oxygen were available, both thanks to lots of photosynthesis. Animals living then could thank photosynthesis, too. All animals breathe oxygen. Experts think insects were so large then because they had more oxygen to breathe.
The process of making coal starts with photosynthesis. The giant forest plants performed photosynthesis just as modern plants do, but they were so large that they absorbed much more carbon dioxide than plants on Earth do today. What does photosynthesis do? Carbon dioxide is a molecule made of carbon and oxygen atoms. Plants take the carbon and make it into carbohydrates. (Notice the word carbon is in here, too.) They release the oxygen into the air. Three hundred million years ago, the air was richer in oxygen than it is today. It contained 35% oxygen instead of today’s 21%. More plant material and more oxygen were available, both thanks to lots of photosynthesis. Animals living then could thank photosynthesis, too. All animals breathe oxygen. Experts think insects were so large then because they had more oxygen to breathe.
The ancient plants took a lot of carbon from the air and turned it into plant material. Over time, these ancient forests built up thick layers of dead plant material. Eventually, it turned into peat. As time went on, the carbon-rich peat was buried and
pressed together as new material piled on top. Meanwhile, the climate changed rapidly, becoming cooler and drier. The rainforests shrank to isolated pockets that were still warm and wet. Ancient plants in those pockets survived. Relatives of those
plants survive today but in smaller forms.
Vast underground coal deposits are all that remain of these once-great forests. Humans have discovered ways to use the energy stored in coal. Coal plants burn coal to generate steam that is used to spin turbines. The turbines generate electricity for our homes, businesses, and factories.
Coal’s carbon journey is a warning.
Vast underground coal deposits are all that remain of these once-great forests. Humans have discovered ways to use the energy stored in coal. Coal plants burn coal to generate steam that is used to spin turbines. The turbines generate electricity for our homes, businesses, and factories.
Coal’s carbon journey is a warning.
Figure A.2.6.17 – Ancient forests were filled with giant ferns.
The burning of coal has a problem. When it burns, carbon is again released into the air as carbon dioxide. Although carbon dioxide is good for plants, too much of it in the air is a problem. It produces a blanket of gas that holds in the Sun’s heat. The
air becomes increasingly warmer, which causes climate change.
The great carboniferous ecosystem almost died because of rapid climate change. No one knows why the climate cooled so fast back then. The vast forests took lots of carbon dioxide from the air. The warming blanket might have grown too thin.
Today, scientists know that burning fossil fuels are warming our climate rapidly. Many of our modern ecosystems are showing signs that they are in trouble.
The great carboniferous ecosystem almost died because of rapid climate change. No one knows why the climate cooled so fast back then. The vast forests took lots of carbon dioxide from the air. The warming blanket might have grown too thin.
Today, scientists know that burning fossil fuels are warming our climate rapidly. Many of our modern ecosystems are showing signs that they are in trouble.
Figure A.2.6.18 – Forests absorb large amounts of carbon dioxide from the air.
Figure A.2.6.19 – Using fossil fuels releases carbon that has been trapped for millions of years.
Figure A.2.6.20 – The carbon dioxide released by burning fossil fuels contributes to climate change.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to guide your learning.
Unit A Lesson 6 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps – if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
- DOWNLOAD the self-check quiz by clicking here.
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- COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
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REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
- SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
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Self-Check Time!
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Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.
Energy flows through an ecosystem in one direction. It enters when plants absorb the Sun’s energy. Then, it is used by organisms. Carbon cycles through the ecosystem over and over again. It enters plants as carbon dioxide. It enters animals
when they eat the plants. It returns to the air and soil when organisms die and decompose. Then, plants can use the carbon again.
Water cycles through ecosystems. Rain or snow falls onto land, rivers, and oceans. Animals drink water from ponds, rivers, lakes, and oceans. Plants soak up water from the soil through their roots. Water evaporates from surfaces back into the
air to form clouds. The cycle repeats with rain or snow.
Living organisms are 19% carbon. They must get carbon from the environment to grow. If carbon dioxide disappeared from the air, plants would die. Animals not only would starve; they would have insufficient oxygen because plants release oxygen
into the air. All life eventually would die. However, carbon cycles very slowly through geological (non-living) processes. Earth maintains carbon dioxide in the air through processes such as volcanic eruptions. Even if there were no life on
Earth, carbon would still cycle slowly among air, rock, and water.
No, the water cycle does not require living organisms to operate. Water cycles among air, land, and water all by itself. This cycle is driven by the Sun’s energy and differences in temperature. The Sun warms water and helps it evaporate into
the air. High in the cold atmosphere, water condenses into clouds. Eventually, water falls as rain, hail, or snow. It runs into rivers and into oceans to evaporate again. This cycle does not require organisms to operate.
Are plants and animals dependent on each other for carbon dioxide and oxygen is an interesting question. To answer, think about it in a different way. What if we discovered a planet with a water cycle and a carbon cycle but the air contained
no oxygen and, therefore, no life on it? If we wanted to build an ecosystem on it, what kind of organisms should we start with? We would have to start with plants because plants can survive without animals. After a long time, plants would
increase oxygen in the atmosphere. Then, we could add some animals. This is the order in which life on Earth evolved. Plants can live without animals, but animals cannot live without plants.