Earth as a System

Earth as a SystemChapter 2StandardsSES1e . Identify the transformations and major reservoirs that make up the rock cycle, hydrologic cycle, carbon cycle, and other important geochemical cycles.SES6c. Explain how geological and ecological processes interact through time to cycle matter and energy, and how human activity alters the rates of these processes (e.g. fossil fuel formation and combustion)Earth BasicsEarth is the third planet from the sun in our solar system.Earth formed about 4.6 billion years ago and is made mostly of rock.Approximately 70% of Earths surface is covered by a thin layer of water known as the global ocean.Earth is an oblate sphere, or a slightly flattened sphere. Earths pole-to-pole circumference is 40,007 km. Its equatorial circumference is 40,074 km.Earths average diameter is 12,756 km.Section 1Oblate sphere

Earths InteriorScientists have made important discoveries about Earths interior through studies of seismic waves.

Seismic waves are vibrations that travel through Earth and that are caused by earthquakes and by explosions near Earths surface.

By studying seismic waves as they travel through Earth, scientists have determined that Earth is made up of three major compositional zones and five major structural zones.Compositional Zones of Earths Interiorcrust the thin and solid outermost layer of Earth that lies above the mantleOceanic crust, which lies under the oceans, is only 5 to 10 km thick. The continental crust varies in thickness from 15 km to 80 km.

mantle in Earth science, the layer of rock that lies between Earths crust and coreThe mantle is nearly 2,900 km thick and makes up almost two-thirds of the planet.

core the central part of Earth that lies below the mantleThe center of Earth is a sphere composed mainly of nickel and iron whose radius is about 3,500 km.

Compositional Zones of Earths Interior, continued

Structural Zones of Earths InteriorThe three compositional zones of Earths interior are divided into five structural zones.

lithosphere the solid, outer layer of Earth that consists of the crust and the rigid upper part of the mantleThe rigid lithosphere is between 15km and 300 km thick.

asthenosphere the solid, plastic layer of the mantle beneath the lithosphere; made of mantle rock that flows very slowly, which allows tectonic plates to move on top of itThe plastic asthenosphere is about 200 km thick.Structural Zones of Earths Interior, continuedmesosphere literally, the middle sphere; the strong, lower part of the mantle between the asthenosphere and the outer coreThe mesosphere reaches from the bottom of the asthenosphere to a depth of about 2,900 km.

Below the mesosphere is the liquid outer core.

The outer core surrounds the solid inner core, which begins at a depth of 5,150 km.Earths InteriorThe diagram below shows the layers of Earths interior.

Earths GravityGravity is the force of attraction that exists between all matter in the universe.Newtons Law of GravitationDepends on the masses of the objects and the distance between them.The larger and closer together, the stronger the gravity between the objects will be.Earth pulls objects toward the center of the planet (measured in Newtons (N).Earth as a SystemEarth system is a result of interaction between matter and energy.Matter anything having mass and volume. Made up of atomsEnergy ability to do work. Can be transferred by heat, light, vibrations, or electromagnetic waves.A system is described by the way that matter and energy are transferred within the system or to and from other systems.Closed energy and matter do not enter or leave Open energy and matter must be added or removedSection 2Earths Four SpheresMatter on Earth is in solid, liquid, and gaseous states. The Earth system is composed of four spheres that are storehouses of all of the planets matter.

The Atmospherea mixture of gases that surrounds a planet or moon

The atmosphere provides the air you breathe and shields Earth from the suns harmful radiation.

Earths Four Spheres, continuedThe Hydrosphere

hydrosphere the portion of Earth that is water

Water covers 71% of Earths surface.

Water in the hydrosphere occur in the form of oceans, lakes, rivers, streams, glaciers and ice sheets, and groundwater.

Earths Four Spheres, continuedThe Geosphere

geosphere the mostly solid, rocky part of Earth; extends from the center of the core to the surface of the crust

The geosphere includes all of the rock and soil on the surface of the continents and on the ocean floor.

The geosphere also includes the solid and molten interior of Earth.

Earths Four Spheres, continuedThe Biosphere

biosphere the part of Earth where life exists; includes all of the living organisms on Earth

The biosphere is composed of all of the forms of life in the geosphere, in the hydrosphere, and in the atmosphere, as well as any organic matter that has not decomposed.

The biosphere extends from the deepest parts of the ocean to the atmosphere a few kilometers above Earths surface.

Earths Energy Budget1st Law of Thermodynamics energy cannot be created or destroyed, only transferred between systems.Transfer of energy between Earths spheres are parts of the energy budgetCycles in the Earth SystemReservoir is a place where matter or energy is storedCycle is a group of processes in which matter and energy repeatedly move through a series of reservoirs.Nitrogen Cycle

nitrogen inatmosphereanimalsdenitrifyingbacterianitrifyingbacterianitrifyingbacteriaammoniumammonificationdecomposersplantnitrogen-fixingbacteria in soilnitrogen-fixingbacteria in rootsnitratesnitritesCarbon Cycle

Water Cycle

21Ecosystems of the BiosphereEcology is the study of the complex relationships between living things and their nonliving, or abiotic environment.

ecosystem is a community of organisms and their abiotic environment

An ecosystem may be as large as an ocean or as small as a rotting log. The largest ecosystem is the entire biosphere.

Section 3Ecosystems, continuedOrganisms that make their own food are called producers. Most producers use energy from the sun to produce their own food.

Consumers are organisms that get their energy by eating other organisms. Consumers may get energy by eating producers or by eating other consumers.

Some consumers get energy by breaking down dead organisms. These consumers are called decomposers.

To remain healthy, an ecosystem needs to have a balance of producers, consumers, and decomposers.

Balancing Forces in Ecosystems, Energy Transfer

The ultimate source of energy for almost every ecosystem is the sun.

Producers, such as plants, capture solar energy by a chemical process called photosynthesis. This captured energy then flows through the ecosystem from the producers, to the consumers, and finally to the decomposers.

As matter and energy cycle through an ecosystem, chemical elements are combined and recombined. Each chemical change results in either the temporary storage of energy or the loss of energy.

The largest population that an environment can support at any given time is called the carrying capacityTrophic LevelsEnergy moves from one trophic level to another

SunProducerConsumerConsumerEnergy Pyramid

Balancing Forces in Ecosystems, continuedEnergy Transfer, continued

An energy pyramid is one way to see how energy is lost as it moves through the ecosystem.

Producers form the base of the pyramid. Consumers that eat the producers are the next level of the pyramid. Animals that eat those consumers form the upper levels of the pyramid.

As you move up the pyramid, more energy is lost at each level. Therefore, the least amount of energy is available to organisms at the top of the pyramid.

Balancing Forces in Ecosystems, continuedFood Chains and Food Webs

The sequence in which organisms consume other organisms can be represented by a food chain or by a food web.

food web a diagram that shows the feeding relationships among organisms in an ecosystemFood Chain

VocabularyCrustMantleCoreLithosphereAsthenosphereMesosphereSystem

AtmosphereHydrosphereGeosphereBiosphereEcosystemCarrying capacityFood web

Review1.The crust and the rigid upper part of the mantle are found in what part of the Earth?

A. the asthenosphereB. the lithosphereC. the mesosphereD. the stratosphereReview1.The crust and the rigid upper part of the mantle are found in what part of the Earth?

A. the asthenosphereB. the lithosphereC. the mesosphereD. the stratosphereReview2. How are scientists able to study the composition and size of the interior layers of Earth?

A. by direct observationB. by analyzing surface rock samplesC. by using seismic wavesD. by deep-drilling into the interior layersReview2. How are scientists able to study the composition and size of the interior layers of Earth?

A. by direct observationB. by analyzing surface rock samplesC. by using seismic wavesD. by deep-drilling into the interior layersReview3. Which of the following methods of internal energy transfer drives volcanic activity on Earths surface?

A. radioactive decayB. convectionC. kinetic transfer D. conduction3. Which of the following methods of internal energy transfer drives volcanic activity on Earths surface?

A. radioactive decayB. convectionC. kinetic transfer D. conductionReviewReview4. Earths primary external energy source is

A. cosmic radiation.B. the moon.C. distant stars.D. the sun.Review4. Earths primary external energy source is

A. cosmic radiation.B. the moon.C. distant stars.D. the sun.Review5. What do decomposers break down to obtain energy?

Review5. What do decomposers break down to obtain energy?

dead organisms

Review6. What scientific principle states that energy can be transferred but that it cannot be created or destroyed?

Review6. What scientific principle states that energy can be transferred but that it cannot be created or destroyed?

First Law of Thermodynamics

Review7. Which layer of Earths interior does not transmit S waves?

A. layer BB. layer CC. layer D D.layer E

Review7. Which layer of Earths interior does not transmit S waves?

A. layer BB. layer CC. layer D D.layer E