Ecosystems and EnergyEcosystems and Energy

Chapter 3Chapter 3

What is Ecology?What is Ecology?

EcologyEcology-- the study of systems that include the study of systems that include

interactions among organisms and interactions among organisms and between organisms and their between organisms and their abioticabiotic environment.environment.

BioticBiotic AbioticAbiotic

EnergyEnergy EnergyEnergy- the capacity or ability to do - the capacity or ability to do

workwork Potential energy vs. kinetic energyPotential energy vs. kinetic energy

1. First Law of Thermodynamics1. First Law of Thermodynamics Energy can’t be created or destroyed (but it can Energy can’t be created or destroyed (but it can

change forms)change forms)

2. Second Law of Thermodynamics2. Second Law of Thermodynamics when energy is converted some of it is degraded when energy is converted some of it is degraded

into heat that disperses into the environment.into heat that disperses into the environment.

Heat and Heat and kinetic kinetic energyenergyconvertedconverted

Potential Potential energyenergy

Kinetic Kinetic energyenergy

PhotosynthesisPhotosynthesis

Light energy from the sun in captured and Light energy from the sun in captured and converted into chemical energyconverted into chemical energy

Who uses this?Who uses this? autotrophsautotrophs

RespirationRespiration

CC66HH1212OO66 + O + O22 →→ CO CO2 2 + H+ H22O + energyO + energy Makes the chemical energy stored Makes the chemical energy stored

in glucose and other food molecules in glucose and other food molecules available to the cell for work available to the cell for work (moving, growing, etc.)(moving, growing, etc.)

Life without the SunLife without the Sun Chemosynthesis-Chemosynthesis-

Flow of Energy Through Flow of Energy Through EcosystemsEcosystems

ProducersProducers- - autotrophsautotrophs Consumers-heterotrophsConsumers-heterotrophs

Primary consumersPrimary consumers Secondary consumersSecondary consumers Tertiary consumersTertiary consumers detritivoresdetritivores decomposersdecomposers

Flow of EnergyFlow of Energy

Food Chain-Food Chain- energy from food energy from food passes from organism to organism in passes from organism to organism in a sequencea sequence

Trophic levels- Trophic levels- each level or link in a each level or link in a food chain/foodwebfood chain/foodweb

Food Web- Food Web- more realistic model of more realistic model of flow of energy and materials through flow of energy and materials through an ecosysteman ecosystem

Human ImpactHuman Impact

Ecological PyramidsEcological Pyramids EcologicalEcological NumbersNumbers BiomassBiomass EnergyEnergy

The transfer between trophic levels is The transfer between trophic levels is <20%<20%

Why?Why?

How can more people be supported on Earth when there is a limited supply of resources?

Human Population GrowthHuman Population Growth

It depends on what they are eating…

ProductivityProductivity Gross primary productivity (GPP)-Gross primary productivity (GPP)-

This is the amount of light energy that is This is the amount of light energy that is converted into chemical energy converted into chemical energy

Net primary productivity (NPP)- GPPNet primary productivity (NPP)- GPP minus the energy used by the primary minus the energy used by the primary producers for respiration producers for respiration . .

Human ImpactHuman Impact

Southern Hemisphere Southern Hemisphere and whale huntingand whale hunting

OzoneOzone Global warmingGlobal warming

PracticePractice Fox eats – rabbit and miceFox eats – rabbit and mice Rabbit eats- grassRabbit eats- grass Mouse eats- grass and grasshopperMouse eats- grass and grasshopper Grasshopper eats- grassGrasshopper eats- grass Golden eagle- eats rabbit, snake, and foxGolden eagle- eats rabbit, snake, and fox Snake eats- miceSnake eats- mice Barn owl- eats miceBarn owl- eats mice Humans eat- rabbitHumans eat- rabbit Draw a food web and identify the Draw a food web and identify the

consumers and producers. ID the consumers and producers. ID the primary, secondary, and tertiary primary, secondary, and tertiary consumersconsumers