The Earth’s Spheres

David Hart

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Printed: August 19, 2014

AUTHORDavid Hart

www.ck12.org Chapter 1. The Earth’s Spheres

CHAPTER 1 The Earth’s Spheres

Lesson Objectives

• Describe how Earth consists of multiple systems and how those systems shape the Earth.• Explain how Earth’s systems are dynamic and react to human caused changes.• Explain how scientists examine changes to these systems to help public officials make informed decisions.

Vocabulary

• Biosphere• Geosphere• Atmosphere• Hydrosphere• Feedback Loop

Introduction

Earth consists of many systems that help shape the structure of the Earth. These systems are often categorized intodifferent spheres, or locations that the systems affect. Let’s look at the Earth’s many spheres and how human activityaffects them.

Biosphere

FIGURE 1.1

One the most unique features of Earth is its abundance of life. The b iosphere is the region of the earth that isoccupied by living organisms. The system of all living organisms is an incredibly elogent and complicated system.

Human Influences

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Humanity itselves live in the biosphere and has vast effects on ecosystems. Many human activities have disruptednatural processes. For example, human hunting has caused some animals to become prematurely endangered due tounnatural predation. Also, human buildings and structures have removed natural habitats of plant and animal lifes.

Many animals have adapted to the changes caused by humans. Some animals have switched habitats or evenbehaviors in order to survive. For example, one species of moth was able to change the color of its wings inorder to survive during the Industrial Revolution (to read more, click here

Atmosphere

FIGURE 1.2

Earth contains a large number of gases that remain near its surface. The atmosphere is this envelope of gasessurrounding the Earth’s surface. The atmosphere is essential for life on Earth. It contains the gases needed forphotosythesis and respiration, which is essential to the oxygen cycle. Also, greenhouse gases help keep the earth ata temperature where water is in liquid form.

Human Influences

For most of the Earth’s history, humans have had very little affect on the atmosphere. However, humanity had avery abrupt increase of influence at the start of Industrial Revolution. The new coal burning factories were quicklyadopted because of the massive increase of productivity. However, the burning of coal releases harmful pollutantsinto the atmosphere. Today, society continues to release pollutants into the atmosphere with coal and gasolineburning from power plants and cars.

The extremity of human caused pollutants is causing many scientists to study the effects of these pollutants to theatmosphere. Many scientists beleive that these chemicals in the air are causing an unnatural increase in temperatureacross the Earth’s surface. This idea is known as ’global warming’. In order to counter this effect, many efforts havebeen taken to try and reduce the number of airborn pollutants.

Hydrosphere

Water is essential key to the survival of life. Fortunately, the Earth contains large amounts of water in various forms.The hydrosphere is the set of all water on the earth’s surface, such as lakes, seas, and oceans.

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FIGURE 1.3

Human Influences

Humanity has long tried to tap into the world’s various water resources. The creation of water collectors such asresvoirs, dams, and canals change the course water takes. This can affect the natural ecosystems these water sorucespreviously supplied. Also, humans have built many ocean structures, such as boats, oil rigs, and bouys. Thesestructures have minimal effect compared to the vastness of the ocean.

One behavior that has had a negative impact is water waste pollutants. In the past, large amounts of waste and debrishave drained into lakes and oceans, destroying species that live in those systems. Now, much effort has been putforth to remove hazards from water before returning it to oceans (to see this in action, click here

Geosphere

The geosphere is the set of all material that makes up the earth’s structure, including the mantle, lithosphere, crust,hydrosphere, and atmosphere.

Human Influences

In the ’Resources’ chapter, we discussed the many mineral materials that humans have tried to gather throughouthistory. Most of that collection occured through mining and drilling for them. These proccesses change the landscapeof the earth, and sometimes can even cause unnatural earthquakes. Other changes include consruction of buildings,bridges, and dams. Some changes to the earths landscapes can destroy some ecosystems and cause others to relocate.

Public Policy

As human activities have increased, more and more effort has been put forth to reduce human caused changes to theearth’s sphreres. In order to do this, scientists must perform careful analyses on the affect of human activities. Onesuch analysis comes through monitoring feedback loops, which are changes to systems that continue to affect futureoutcomes. For example, as human-caused air polluntants destroy the ozone, it raises the temperature of the Earth,and that increase in temperature affects the enviroment in ways that create even more heat.

In order to combat these unnatural changes to the earth’s spheres, public policies are often placed to preventinnappropriate activity. For example, nature resereves can be mainted to help preserve large portions of the biosphere.Also, hunting seasons are often enforced to restrict killing specific animals during their mating periods, which helpskeep balance in ecosystem food chain cycles.

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FIGURE 1.4An open-pit mining site.

Other examples of public policies include emission checks on cars to reduce atmospheric pollutants, sewage treat-ment plants to reduce water based pollutants, human water usage restrictions during droughts, mining and drillingrestrictions, and house and building codes to reduce the effects to natural systems.

Lesson Summary

• The Earth consists of many dynamic systems often called spheres.• These spheres are highly affected by human activities.• The spheres are dynamic and adapt to changes.• Public policy has been introduced to reduce human caused change to systems.

Review Questions

1. Imagine you want to build a factory near Lake Michigan. What spheres might your factory affect and howmight reduce that affect?

2. Why is it important to reduce change to the Earth’s spheres?3. An invasive species is when a human brings a foreign species into an ecosystem. What spheres might an

invasive species affect and why?

Points to Consider

• Why have humans just recently become interested in their affect Earth’s spheres? What type of events mayhave sparked this interest?

• Many of the spheres overlap (ex. the geosphere includes the atmosphere), so how come scientists still considerthese spheres seperately?

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