What does a car need to run?What does a car need to run? What does an ipod need to work?What does an ipod need to work? What do we need to survive?What do we need to survive? If all these things need a power/energy If all these things need a power/energy

source, what is the earth’s source?source, what is the earth’s source?

13.2 Energy Systems13.2 Energy Systems

How Energy is TransferredHow Energy is Transferred

Energy (heat or light) is transferred in one of Energy (heat or light) is transferred in one of the following ways:the following ways:

RadiationRadiation ConvectionConvection AdvectionAdvection ConductionConduction

RadiationRadiation

the transfer of energy by electromagnetic the transfer of energy by electromagnetic (light) waves (light) waves (electromagnetic spectrum)(electromagnetic spectrum)

does not require a medium to travel through does not require a medium to travel through (i.e. can travel through a vacuum)(i.e. can travel through a vacuum)

travels in straight linestravels in straight lines is emitted (given off) by all matteris emitted (given off) by all matter the the onlyonly form of energy given to us by the form of energy given to us by the

sunsun

ConvectionConvection transfer of energy by vertical movement of transfer of energy by vertical movement of

particles in a particles in a fluidfluid (liquid/gas) (liquid/gas) as the particles gain energy they move faster, as the particles gain energy they move faster,

take up more space, become less dense, and take up more space, become less dense, and then can rise through the fluid they are inthen can rise through the fluid they are in

this can create this can create convection currentsconvection currents this method of heat transfer is very important this method of heat transfer is very important

to weatherto weather

AdvectionAdvection

The horizontal transfer of energy through The horizontal transfer of energy through the collision of particles in a liquid or gasthe collision of particles in a liquid or gas

Energy moves horizontallyEnergy moves horizontally

ConductionConduction the transfer of energy which the transfer of energy which

occurs when a particle with occurs when a particle with high energy hits a particle high energy hits a particle with lower energywith lower energy

thus thus energy is passedenergy is passed through an object from through an object from atom to atomatom to atom

only occurs in only occurs in solidssolids, since , since the particles must be close the particles must be close together for frequent together for frequent collisions to occur readilycollisions to occur readily

What energy is needed to survive on What energy is needed to survive on Planet Earth?Planet Earth?

Hint:Hint:

Solar EnergySolar Energy Where does it come from?Where does it come from?

produced by nuclear fusion reactions in the sunproduced by nuclear fusion reactions in the sun

How does Solar Energy reach Earth?How does Solar Energy reach Earth? Radiant energy travels in waves of different energy Radiant energy travels in waves of different energy

levels, collectively known as the Electromagnetic levels, collectively known as the Electromagnetic SpectrumSpectrum

In order from lowest to highest energy level:In order from lowest to highest energy level:• RadioRadio• MicrowaveMicrowave• InfraredInfrared• VisibleVisible• UltravioletUltraviolet• X-raysX-rays• GammaGamma

Electromagnetic SpectrumElectromagnetic Spectrum

AlbedoAlbedo

When solar energy strikes an object, some of the When solar energy strikes an object, some of the energy is absorbed and some is reflectedenergy is absorbed and some is reflected

Albedo is a measurement of the percentage of light Albedo is a measurement of the percentage of light which a material will reflectwhich a material will reflect Polar Ice Cap – High or Low?Polar Ice Cap – High or Low?

• Answer: HighAnswer: High Black Roof – High or Low?Black Roof – High or Low?

• Answer: LowAnswer: Low Bare Soil – High or Low?Bare Soil – High or Low?

• Answer: LowAnswer: Low

The higher the albedo, the less energy absorbedThe higher the albedo, the less energy absorbed

Heat Capacity:Heat Capacity: a measure of how much heat a substance must a measure of how much heat a substance must

absorb to increase its temperature by 1degree Cabsorb to increase its temperature by 1degree C if a substance absorbs a lot of heat, yet its if a substance absorbs a lot of heat, yet its

temperature rises slowly, then it has a high heat temperature rises slowly, then it has a high heat capacitycapacity

think of the Yoho Lake & a sandy beach in the think of the Yoho Lake & a sandy beach in the summersummer they both absorb the same amount of heatthey both absorb the same amount of heat

the water stays cold because it can absorb a lot of the water stays cold because it can absorb a lot of heat without its temperature rising, the sand on heat without its temperature rising, the sand on the other hand gets very hotthe other hand gets very hot

Heat SinkHeat Sink

an object which absorbs energy and an object which absorbs energy and becomes warmerbecomes warmer

a substance with a high a substance with a high heat capacityheat capacity makes a good heat sinkmakes a good heat sink

water has a high heat capacity and so is a water has a high heat capacity and so is a good heat sink, while rocks have a low good heat sink, while rocks have a low heat capacity heat capacity

See Table in TextSee Table in Text

Absorption and ReflectionAbsorption and Reflection solar energy entering the atmosphere can be solar energy entering the atmosphere can be

either absorbed or reflectedeither absorbed or reflected both absorption and reflection can occur with the both absorption and reflection can occur with the

air, clouds and the earth’s surfaceair, clouds and the earth’s surface approximately 70% of the sunlight that reaches approximately 70% of the sunlight that reaches

earth is earth is absorbedabsorbed 44% heat the Earth’s land surface and air44% heat the Earth’s land surface and air 25% heat the water and evaporate some water25% heat the water and evaporate some water 1% creates wind1% creates wind Less than 1% is used for photosynthesisLess than 1% is used for photosynthesis

approximately 30 % is approximately 30 % is reflectedreflected(air 6%, clouds 20%, earth 4%)(air 6%, clouds 20%, earth 4%)

Why is Solar Energy Important?Why is Solar Energy Important? all forms of life on earth are dependent on solar all forms of life on earth are dependent on solar

energy for lifeenergy for life needed for plants to grow and to keep earth warm needed for plants to grow and to keep earth warm

enough for survivalenough for survival Reminder: less than 1% is used by Photosynthesis.

• PHOTOSYNTHESIS – The process by which The process by which green plants use sunlight to produce sugar.green plants use sunlight to produce sugar.

COCO22 + 2H + 2H22O + sunlight ---> OO + sunlight ---> O22 + (C + (C66HH1212OO66))nn + H + H22OO

or...or... carbon dioxide + water + sunlight ---> oxygen + carbohydrate + watercarbon dioxide + water + sunlight ---> oxygen + carbohydrate + water

ENERGY MOVEMENT ENERGY MOVEMENT IN ECOSYSTEMSIN ECOSYSTEMS

Chapter 1.11Chapter 1.11

ENERGY MOVEMENT IN ECOSYSTEMSENERGY MOVEMENT IN ECOSYSTEMS

Chapter 1.11

Of the less than 1% (0.023%) that is used Of the less than 1% (0.023%) that is used

for photosynthesis, how does that energy for photosynthesis, how does that energy disperse throughout disperse throughout food chainsfood chains and and food food webs?webs?

FOOD WEB FOOD WEB – a series of interlocking food – a series of interlocking food chainschains

When talking about food webs and energy, When talking about food webs and energy, new terms are used to describe producers new terms are used to describe producers and consumers/decomposers.and consumers/decomposers.

AUTOTROPHS

Plants or algae which make their own food Plants or algae which make their own food using the sun’s energy through using the sun’s energy through photosynthesisphotosynthesis

Previously called producersPreviously called producers

HETEROTROPHSHETEROTROPHS

Animals, fungi and bacteria that must eat Animals, fungi and bacteria that must eat or decompose plants or animals ( and their or decompose plants or animals ( and their waste) to get their energy.waste) to get their energy.

Previously called consumersPreviously called consumers Also decomposersAlso decomposers

WHY NEW TERMS?WHY NEW TERMS?

Each of the feeding levels ( consumer, primary Each of the feeding levels ( consumer, primary consumer, secondary consumer ) is called a consumer, secondary consumer ) is called a trophic level. trophic level.

Every time something is consumed in a food Every time something is consumed in a food chain, energy is passed along.chain, energy is passed along.

However, less and less energy is passed on However, less and less energy is passed on each time because some of the energy is used each time because some of the energy is used for life processes ( maintaining body for life processes ( maintaining body temperature, digestion, growing, movement, etc)temperature, digestion, growing, movement, etc)

ECOLOGICAL PYRAMIDECOLOGICAL PYRAMID

ECOLOGICAL PYRAMIDECOLOGICAL PYRAMID

Third

Trophic level

Secondary Consumers

Second Trophic Level

Primary Consumers

First Trophic Level

Producers

Numbe

r of O

rgan

ism

s

Decre

ases

Available Energy

Decreases

Energy from the Sun

With these new terms and previous old With these new terms and previous old terms we can place labels on organisms terms we can place labels on organisms within food chains and food webs.within food chains and food webs.

Lets look at Handout: Lets look at Handout: Energy loss in a Energy loss in a food chainfood chain

Energy Loss in Food ChainsEnergy Loss in Food Chains

ENERGY LOSS IN A FOOD ENERGY LOSS IN A FOOD CHAINCHAIN

The higher the trophic level in the food The higher the trophic level in the food chain, the more energy is lost. chain, the more energy is lost.

Consuming plants, which are the Consuming plants, which are the lowest trophic level, allows for the lowest trophic level, allows for the least amount of energy to be lost.least amount of energy to be lost.

A SIMPLE FOOD WEBA SIMPLE FOOD WEB

More Complex Food WebMore Complex Food Web

HOMEWORK HOMEWORK

TEXT PAGE 39TEXT PAGE 39 QUESTIONS: #1-6, 9,10QUESTIONS: #1-6, 9,10

Homework Answers: p. 39Homework Answers: p. 39

1.1. Feeding level on a food chain.Feeding level on a food chain.

2.2. Autotrophs produce their own food using Autotrophs produce their own food using the sun’s energy.the sun’s energy.

3.3. Heterotroph must consume its food for Heterotroph must consume its food for energy.energy.

4.4. A secondary consumer eats meat due to A secondary consumer eats meat due to its trophic level.its trophic level.

Homework Answers: p. 39Homework Answers: p. 39

5.5. A top carnivore eats lower level A top carnivore eats lower level organisms and is not eaten by anyone. organisms and is not eaten by anyone. Ex. Owls, sharks, polar bears.Ex. Owls, sharks, polar bears.

6.6. A food chain is a single path from A food chain is a single path from producer to top carnivore. A food web is producer to top carnivore. A food web is interconnected food chains.interconnected food chains.

Homework Answers: p. 39Homework Answers: p. 39

9.9. The plant uses the rest of it’s energy on The plant uses the rest of it’s energy on photosynthesis, respiration, reproduction, photosynthesis, respiration, reproduction, etc.etc.

10.10. The mouse uses energy for growth, The mouse uses energy for growth, movement, digestion, etc.movement, digestion, etc.