THE SPHERES OF THE THE SPHERES OF THE EARTHEARTH

Wednesday, April 19, 2023

As you can see from the previous slides the As you can see from the previous slides the earth is made up of a number of spheres, the earth is made up of a number of spheres, the most important are:most important are:

The AtmosphereThe Atmosphere

The LithosphereThe Lithosphere

The HydrosphereThe Hydrosphere

The BiosphereThe Biosphere

The many spheres of the The many spheres of the earth:earth:

Can you name them?Can you name them?

The main focus of physical geography is on the The main focus of physical geography is on the LIFE LIFE LAYER LAYER of the earth: a shallow zone of the lands and of the earth: a shallow zone of the lands and oceans containing most of the world’s organic life oceans containing most of the world’s organic life (also called Biosphere).(also called Biosphere).

• All of the earth’s systems interact to support the All of the earth’s systems interact to support the Biosphere. Biosphere.

•This is where we will begin our study of Physical This is where we will begin our study of Physical Geography.Geography.

Two diagrams illustrating the Biosphere (life layer) of the earth

Here is another way of looking at the interaction between spheres.

Notice:

The Biosphere connects with all three.

70% of the earth’s surface is covered by 70% of the earth’s surface is covered by water. If the earth was totally flat, earth would water. If the earth was totally flat, earth would be covered by water at a depth of 12,000 ft.be covered by water at a depth of 12,000 ft.

It fills in the lower parts of the lithosphere.It fills in the lower parts of the lithosphere.

Water connects the atmosphere with the Water connects the atmosphere with the lithospherelithosphere

CryosphereCryosphere is the frozen hydrosphere. This is the frozen hydrosphere. This even includes the frozen ground usually called even includes the frozen ground usually called permafrostpermafrost

The HydrosphereThe Hydrosphere

A gaseous shell that surrounds the earth, A gaseous shell that surrounds the earth, made mostly of oxygen, nitrogen, carbon and made mostly of oxygen, nitrogen, carbon and hydrogenhydrogen

it dictates the climate: this governs the it dictates the climate: this governs the exchange of heat and water between the exchange of heat and water between the atmosphere and the groundatmosphere and the ground

Divided up into other spheres: stratosphere, Divided up into other spheres: stratosphere, troposphere, etc.troposphere, etc.

The AtmosphereThe Atmosphere

The LithosphereThe Lithosphere Thin outer crust that surrounds the earth.Thin outer crust that surrounds the earth.

Platform of lifePlatform of life

the lithosphere also supplies valuable nutrients that the lithosphere also supplies valuable nutrients that pass from rock to soil to plants and finally to us.pass from rock to soil to plants and finally to us.

Considered to be a brittle shell of solid rock.Considered to be a brittle shell of solid rock.

Under force it could be cracked, warped , buckled.Under force it could be cracked, warped , buckled.

The average depth is about 16 kmThe average depth is about 16 km

Under the oceans, depth is about 5 kmUnder the oceans, depth is about 5 km

Floats on top of the Aesthenosphere (more on this Floats on top of the Aesthenosphere (more on this later in the course)later in the course)

These spheres interact with one another to create These spheres interact with one another to create The BiosphereThe Biosphere or the earth’s or the earth’s Life Layer. Life Layer.

It is the biosphere that makes the earth unique It is the biosphere that makes the earth unique among the other planets we know of. Water in three among the other planets we know of. Water in three states.states.

The biosphere can be further broken down into what The biosphere can be further broken down into what are called biomes or ecozones or ecoregions. are called biomes or ecozones or ecoregions.

Biomes are usually distinguished by their vegetation Biomes are usually distinguished by their vegetation cover. Biomes are really a combination of climate cover. Biomes are really a combination of climate regions, soil regions, vegetation regions and landform regions, soil regions, vegetation regions and landform regions.regions.

The BiosphereThe Biosphere

Vertically, the habitable zone (the biosphere) surrounding the Earth is extremely restricted. The blanket of air extends to an altitude of about 30km and fades away into empty space. The living zone of the air is a layer only 5km high.

If you compare this to the radius of the earth it would be the earth being a regular sized peach and the living zone would be thinner than the fuzz.

On the surface of the earth, some areas are too dry, too wet, too cold, too hot or too rugged to support human life. The most uninhabitable areas on earth is Greenland, Antarctica and the Arctic.

The Atmosphere is the air we breathe. The Hydrosphere is the water of rivers, lakes and oceans, the moisture in soil and air, as well as the snow and ice of the cryosphere. The Biosphere is the habitat of all earthly life. The Lithosphere is the soil and bedrock that cover the Earth’s surface.

Geographers recognize five primary biome types: Geographers recognize five primary biome types:

•ForestForest

•GrasslandGrassland

•SavannaSavanna

•DesertDesert

•TundraTundra

These can be of course further broken down (and These can be of course further broken down (and depending on what book you have the names may depending on what book you have the names may change).change).

The Biosphere Cont’d The Biosphere Cont’d

Planet Earth, by Gary Birchall (John Wilely and Sons)

World Biome Map – Vegetation RegionsWorld Biome Map – Vegetation Regions

The catalyst that creates the biosphere from The catalyst that creates the biosphere from the other spheres is the the other spheres is the SunSun. .

The sun gives the earth energy in the form of The sun gives the earth energy in the form of Solar RadiationSolar Radiation, sometimes called , sometimes called insolationinsolation..

The next slide has a diagram that illustrates The next slide has a diagram that illustrates how the earth distributes this energy. This how the earth distributes this energy. This distribution is called the distribution is called the Earth’s Earth’s Energy Balance Energy Balance or Budget. Much more on this in the slide shows - or Budget. Much more on this in the slide shows - for Introduction #2.for Introduction #2.

The Sun and its RoleThe Sun and its Role

Note: Yellow represents the energy coming from the sun. Orange represents what is absorbed and Red represents what is released back into space - sometimes called the albedo.

Introducing Physical Geography by Strahler and Strahler.

How does the Earth maintain it’s balance after a Volcanic eruption?

How a Geography book called “Geosystems” studies Physical Geography - our course

follows a similar pattern

The earth either absorbs the energy and converts The earth either absorbs the energy and converts it into other types of energy like:it into other types of energy like:

- Fossil Fuels- Fossil Fuels

- Temperature and precipitation - Temperature and precipitation

- Photosynthesis- Photosynthesis

- Winds and Pressure - Winds and Pressure

- The Hydrologic Cycle (see picture next slide)- The Hydrologic Cycle (see picture next slide)

Or it reflects/radiates back into space - Or it reflects/radiates back into space - albedoalbedo..

Introducing Physical Geography by Strahler and Strahler.

Our Earth – A SystemOur Earth – A System

AA good way to understand how the spheres interact good way to understand how the spheres interact with one another is to think of the earth as a with one another is to think of the earth as a SPACESHIP.SPACESHIP.

Spaceships are closed systems (think of the movie Spaceships are closed systems (think of the movie Apollo 13 or the project in Arizona called Biosphere 2, Apollo 13 or the project in Arizona called Biosphere 2, where they actually built a closed system where they actually built a closed system ((http://www.bio2.edu/http://www.bio2.edu/). Spaceships must operate in all ). Spaceships must operate in all kinds of environments - friendly and hostile - so they kinds of environments - friendly and hostile - so they must carry with them all the things needed to support must carry with them all the things needed to support life:life:

Air, Water, food, heatAir, Water, food, heat

Systems

How humans interact in the Earth’s systems

Our Earth – A SystemOur Earth – A System

The spaceship must recycle these things and use The spaceship must recycle these things and use them over and over in an efficient manner.them over and over in an efficient manner.

The ship also needs an efficient waste disposal The ship also needs an efficient waste disposal systemsystem

Each of these items mentioned above are vital. Each of these items mentioned above are vital. They must be in perfect balance. If one of the above They must be in perfect balance. If one of the above should fail, then life will die.should fail, then life will die.

The earth is like this spaceship, but only larger. The The earth is like this spaceship, but only larger. The earth is travelling in space (a hostile environment), but earth is travelling in space (a hostile environment), but it carries all the things necessary for life. it carries all the things necessary for life.

Recently the spaceship earth seems to have a crew Recently the spaceship earth seems to have a crew that doesn’t really care about maintaining these LIFE that doesn’t really care about maintaining these LIFE SUPPORT SYSTEMS. SUPPORT SYSTEMS.

The crew takes them for granted. A few years ago, The crew takes them for granted. A few years ago, the crew (humans) was small, our technology was the crew (humans) was small, our technology was limited, our ability to damage the spaceship was also limited, our ability to damage the spaceship was also limited.limited.

Our Earth – Our SpaceshipOur Earth – Our Spaceship

But today, we can no longer take the systems that But today, we can no longer take the systems that make life possible on earth for granted. We have make life possible on earth for granted. We have grown to an incredible size (6 billion). Our grown to an incredible size (6 billion). Our technology is constantly presenting new threats to technology is constantly presenting new threats to the environment:the environment:

• air pollutionair pollution• oil spillsoil spills• garbagegarbage• waste disposalwaste disposal• toxic wastetoxic waste• CFCsCFCs• carbon dioxide, etc...carbon dioxide, etc...

We must learn all we can about these We must learn all we can about these factors that make up our life support factors that make up our life support

systems. That is where Physical Geography systems. That is where Physical Geography comes in. We must prevent the destruction comes in. We must prevent the destruction

of the physical environment.of the physical environment.

THE FUTURE OF THE EARTH IS AT RISK!THE FUTURE OF THE EARTH IS AT RISK!

Let’s continue our understanding of Let’s continue our understanding of the spaceship earth by introducing the spaceship earth by introducing the earth. Let’s look at the earth’s the earth. Let’s look at the earth’s

basic dimensions and how we basic dimensions and how we measure the earth and places on the measure the earth and places on the

earth.earth.

Go to the slide show entitled: Go to the slide show entitled: Intro_EarthIntro_Earth