Module 2 Intro

1. Module 2 Intro

Module Introduction

Module 2—Biosphere Equilibrium and the Impact of Humans

Module Introduction

In this module you will explore the balancing act of the biosphere and how human activities can disrupt the cycling of matter and energy flow. You will also look at the impact of these activities on the global climate.

You will be looking at the following essential questions in this module:

How are energy, matter, and ecosystem productivity interrelated?

How does the relationship between gas exchange in photosynthesis and cellular respiration influence the composition of the atmosphere?

How do human activities influence the biosphere?

At the end of this module, you will complete a Module Project based on your reflections and research involving the human impact on Canada’s Arctic. When have completed Module 2, go to Module Summary and Assessment for detailed instructions about the project.

Once you have finished your Module Project, you will be ready to complete the final Unit Assessment. This is located in the Unit Conclusion.

1.1. Big Picture

Big Picture

Module 2—Biosphere Equilibrium and the Impact of Humans

Big Picture

“Use what is happening in the Arctic—the Inuit Story—as a vehicle to reconnect us all, so that we may understand that the planet and its people are connected as one.”

—Sheila Watt-Cloutier, Canadian Inuit leader asking members of the US senate to consider how the Arctic is connected to the rest of the world in response to their refusal to sign the Kyoto Protocol (plan to reduce greenhouse gas emissions)

When you watch television, listen to the radio, surf the Internet, or read magazines, you are often bombarded with information about climate change or global warming. All of the information in the media implies there is a direct link between greenhouse gases and climate change. Greenhouse gas emissions actually change the balance of energy and matter in the biosphere, which scientists propose is the cause of global warming.

Albertans contribute to greenhouse gas emissions: therefore, people in Alberta are connected to the balance of energy in the biosphere. Unfortunately, some of the effects of climate change are observed in our own “backyard”—the Canadian Arctic.

A photograph shows a polar bear sitting in open water near an ice floe.

Are you aware that the Canadian Arctic, the biosphere’s air-conditioning unit, is seriously affected by global warming? Do you know that the ice shelves are melting at an alarming rate and that summers in the Arctic are lasting longer than ever before? Do you know that climate change may be negatively affecting polar bears?

You might be asking yourself, “Why should I care about longer summers, ice shelves, and polar bears?” Another question could be, “What’s the big deal about a few degrees of difference in Arctic temperatures?” Scientists believe that the fragile Arctic ecosystem serves as an early-warning system for the entire biosphere!

If one part of this ecosystem is affected, then all of the other systems must also be affected. Do you believe that “the planet and its people are connected as one”? Can you describe how you are connected? If people are all connected as one, then it must be assumed that all the actions taken will affect others—for good or for bad.

So this is the question for Module 2: What effects do humans have on biosphere equilibrium?

To know what effects humans have on biosphere equilibrium, you will need to work through these essential questions:

How are energy, matter, and ecosystem productivity interrelated?
How does the relationship between gas exchange in photosynthesis and cellular respiration influence the composition of the atmosphere?
How do human activities influence the biosphere?

In addition to the lesson assignments and labs, there will be a Module Project to complete. You will be required to prepare a PowerPoint or a multimedia presentation, essay, speech, or storyboard exploring a specific example of how global warming is affecting the Arctic ecosystem in terms of energy and matter.

When you are ready for more information about the project, go to the Module Summary and Assessment for instructions and a rubric identifying how your work will be marked.

1.2. In this Module

In this Module

Module 2—Biosphere Equilibrium and the Impact of Humans

In This Module

Lesson 1—Ecosystem Productivity: A Balance Between Energy and Matter

This lesson looks at how the balance of energy and matter can be observed in the biosphere. Biotic and abiotic processes help to maintain the balance of matter and energy exchange in the biosphere. Productivity is influenced by environmental factors such as sunlight and nutrient availability. As you move on from this module, you will continue to look at how human influence can affect biosphere equilibrium.

How are energy, matter, and ecosystem productivity interrelated?

Lesson 2—Gas Exchange Equilibrium

This lesson will describe the gas exchange equilibrium that exists in the biosphere. As always, the balance can be affected by human activity. Your job is to make sure you can answer the following question and apply what you know when you factor in the consequences of technology:

How does the relationship between gas exchange in photosynthesis and cellular respiration influence the composition of the atmosphere?

Lesson 3—The Ecological Footprint of Humans

This lesson will focus on mankind’s ecological footprint. You will learn about how humans can interfere either intentionally or unintentionally with the cycling of matter. Studying changes to Earth’s atmosphere over recent history will provide an example of how human activity presently affects atmospheric composition. You will then look at the relationship between biogeochemical cycles, atmospheric composition, and the climate. You will explore the following question:

How do human activities influence the biosphere?

Module Assessment

You will be graded according to the work you complete for the lesson assignments and the module project. The module project is the final assignment for Module 2.

1.3. Lesson 1 Intro

Module 2 Lesson 1

Module 2—Biosphere Equilibrium and the Impact of Humans

Lesson 1—Ecosystem Productivity: A Balance Between Energy and Matter

Get Focused

A photograph shows rocks balancing on top of one another. A beach and an ocean are shown in the background.

What is the balancing act that keeps everything together? Are systems unchanging and static? No. In fact, the systems are dynamic. You may have heard the word dynamic used to describe a character who adapts to the environment. Equilibrium on Earth is dynamic—matter and energy fluctuate but are kept in balance by systems within the biosphere. As you look outdoors once again, you will see that the balance between finite and infinite resources can be measured and observed. The question for you to answer is “how?”

As you work through this module, you will be required to answer Reflect on the Big Picture and Reflect and Connect questions from each of the three lessons. These responses will be stored in your course folder. You will be using your responses as a planning tool to respond to the final module written assignment. You do not need to submit the responses to your teacher for assessment, but you may request feedback if it will assist your work towards the module project.

Consider the following question as you complete this lesson:

How are energy, matter, and ecosystem productivity interrelated?

Module 2: Lesson 1 Assignment

Your teacher-marked Module 2: Lesson 1 Assignment requires you to submit a response to the following:

Lab 1: Thought Lab 2.3: Too Much of a Good Thing

You can access your Module 1: Lesson 1 Assignment. You can print off the assignment or save the download to your computer. Your answers can be saved on this document to your course folder.

The other questions in this lesson are not marked by the teacher; however, you should still answer these questions. The Self-Check and Try This questions are placed in this lesson to help you review important information and build key concepts that may be applied in future lessons.

After a discussion with your teacher, you must decide what to do with the questions that are not part of your assignment. For example, you may decide to submit to your teacher the responses to Try This questions that are not marked. You should record the answers to all the questions in this lesson and place those answers in your course folder.

1.4. Page 2

Module 2 Lesson 1 Page 2

Module 2—Biosphere Equilibrium and the Impact of Humans

Explore

Read

Begin Lesson 1 by reading pages 53 and 54 of your textbook. You will be instructed to complete the Thought Lab later on in this lesson.

Ecosystem productivity depends on many things and can be measured. Sometimes productivity can be directly or indirectly affected by human actions.

Self-Check

SC 1. What is productivity?

SC 2. What is significant about algal beds and reefs? (Hint: Refer to “Figure 2.20” on page 53 of your textbook.)

SC 3. Why would the productivity of a tropical seasonal rainforest be greater than tundra? (Hint: Refer to “Figure 2.20” in your textbook.)

Check your work.

Self-Check Answers

SC 1. Productivity is the rate at which an ecosystem’s producers capture and store energy within organic compounds over a certain length of time. Productivity is measured as energy per area per year (J/m2/a) or in biomass (g/m2/a).

SC 2. Algal beds and reefs take up 0.1% of Earth’s surface area but have the highest productivity in terms of energy.

SC 3. The number of producers present in a tropical seasonal forest would be greater, as would the amount of rainfall. There would also be more heat and light available for more of the year than in the arctic.

A Closer Look at Ecosystem Productivity

Following this more in-depth look at productivity, there are Self-Check questions for you to answer.

The following are characteristics of gross productivity:

Gross productivity is the amount of energy trapped in plant material during a specified interval at a given trophic level.
Remember, plants trap only 2% of the solar energy around them.
At least half of this solar energy is lost by cellular respiration as plants must also access energy for their life processes.

The photograph on the left is of a grizzly bear walking on tundra. The photograph on the right shows a leafy green seasonal rainforest similar to forests found in British Columbia.

The following are characteristics of net productivity:

Net productivity is the amount of energy trapped in plant material during a specified interval (time) at a given trophic level minus what is lost by cellular respiration of the organisms at that level (measuring biomass).
One way to determine net productivity is to collect and weigh the plant material produced on 1 m2 of land over a given interval.
One gram of plant material (e.g., stems and leaves), mostly carbohydrates, yields about 20 J of energy when burned or respired.

The following table shows representative values for the net productivity of a variety of ecosystems—both natural and managed. These values are only approximations and are subject to marked fluctuations because of variations in temperature, fertility, and availability of water.

Estimated Net Productivity of a Variety of Ecosystems (kJ/m2/y)
temperate deciduous forest	21 000
tropical rainforest	63 000
tall-grass prairie	8400
desert	2100
coastal marsh	50 200
ocean close to shore	10 500
open ocean	3300
clear lake	3300
lake in advanced state of eutrophication	10 500

Self-Check

SC 4. What happens to the net productivity of an ecosystem?

SC 5. How do people directly and indirectly depend on net productivity?

SC 6. In what other ways do people depend on net productivity to meet their needs?

SC 7. How do humans reduce the net productivity of an area?

Check your work.

Self-Check Answers

SC 4. The net productivity of an ecosystem is harvested by herbivores (deer, insects). Productivity is then transferred down food chains—some is decomposed, and some is stored (growing forests, peat bogs).

SC 5. People directly depend on net productivity by eating plants. Indirectly, people eat other organisms that consume plants or other animal products.

SC 6. For example, people use plant materials for construction, fuel, and for clothing.

SC 7. Humans reduce the net productivity of an area by clearcutting to build roads and houses and to develop agriculture and industry.

1.5. Page 3

Module 2 Lesson 1 Lab

Module 2—Biosphere Equilibrium and the Impact of Humans

Lab

Lab: Too Much of a Good Thing

Increasing ultraviolet radiation (UVR) can have an impact on ecosystems. In "Thought Lab 2.3: Too Much of a Good Thing," you will be analyzing information from readings and a chart in order to form conclusions about the impact of UVR.

Go to Module 2: Lesson 1 Assignment for directions.

This is an illustration of a girl using an umbrella on a sunny day.

Going Beyond

Do a web search using the keywords “biomass energy.” It is an interesting topic and may be a more widely used alternative energy source in your future.

Reflect and Connect

Answer these questions by working your answers into a concise paragraph. How are energy, matter, and ecosystem productivity interrelated? Where do you (humans) fit into this picture? Save your responses to your course folder. Answering these questions will give you some ideas that will be discussed in the unit assessment and module project.

Reflect on the Big Picture

How would ecosystem productivity be affected in the Arctic as a result of climate change?

This is the first of three Big Picture questions that you will answer. The ideas synthesized here will be stored in your course folder for later use in your module project. Your module project will require you to prepare a PowerPoint or multimedia presentation, essay, speech, or storyboard exploring a specific example of how global warming is affecting the Arctic ecosystem in terms of energy and matter. These questions will help you to explore how human influences (science and technology) can have unintended consequences.

You may want to do some research.

Remember to submit the Assignment answers to your teacher as part of your Module 2: Lesson 1 Assignment.

1.6. Page 4

Module 2 Lesson 1 Page 2

Module 2—Biosphere Equilibrium and the Impact of Humans

Lesson Summary

In this lesson you explored the following essential question:

How are energy, matter, and ecosystem productivity interrelated?

You looked at how the balance of energy and matter can be observed in the biosphere. Biotic and abiotic processes help to maintain the balance of matter and energy exchange in the biosphere. Productivity is influenced by environmental factors such as the availability of sunlight and nutrients. You looked at how UV radiation can have an effect on the productivity of an ecosystem. As you continue working in this module, you will continue to look at how the influence of people can affect biosphere equilibrium.

1.7. Lesson 2 Intro

Module 2 Lesson 2