CHAPTER 2 – CHAPTER 2 – PRINCIPLES OF PRINCIPLES OF

ECOLOGYECOLOGY

Section 2-2: Nutrition and Energy Section 2-2: Nutrition and Energy Flow (p.46-57)Flow (p.46-57)

How Organisms Obtain EnergyHow Organisms Obtain Energy An important An important

characteristic of a characteristic of a species niche is how it species niche is how it obtains obtains ENERGYENERGY

Ecologist trace the flow Ecologist trace the flow of energy through of energy through communitiescommunities to discover to discover nutritional relationships nutritional relationships between organismsbetween organisms

How Organisms Obtain EnergyHow Organisms Obtain Energy The ultimate source of energy The ultimate source of energy

for life is the for life is the SUNSUN Plants use the sun’s energy Plants use the sun’s energy

to manufacture food in a to manufacture food in a process called process called PhotosynthesisPhotosynthesis

AutotrophsAutotrophs An organism that uses light An organism that uses light

energy or energy stored in energy or energy stored in chemical compounds to chemical compounds to make energy-rich make energy-rich compoundscompounds Also called a Also called a producerproducer Examples:Examples:

• GrassGrass• TreesTrees• AlgaeAlgae

HeterotrophsHeterotrophs An organism that An organism that

cannot make its cannot make its own food and own food and feeds on other feeds on other organismsorganisms

Can feed on Can feed on autotrophsautotrophs or or other other heterotrophsheterotrophs

HerbivoreHerbivore A heterotroph A heterotroph

that only feeds that only feeds on plantson plants

Examples:Examples:

CarnivoresCarnivores A heterotroph A heterotroph

that only eats that only eats other other heterotrophsheterotrophs

Examples:Examples:

ScavengersScavengers

Do not kill for foodDo not kill for food Eat already dead Eat already dead

animalsanimals Examples:Examples:

Role benefits Role benefits ecosystems – ecosystems – recycles nutrientsrecycles nutrients

OmnivoresOmnivores Organisms that eat Organisms that eat

both plants and both plants and animalsanimals

Examples:Examples:

DecomposersDecomposers

Break down the Break down the complex complex compounds of compounds of dead and decaying dead and decaying plants and animalsplants and animals Nutrient recyclingNutrient recycling

Examples:Examples:

Flow of Matter and Energy in Flow of Matter and Energy in EcosystemsEcosystems

As you eat food, such as an apple, you As you eat food, such as an apple, you consume consume MatterMatter

Matter flows through the levels of an Matter flows through the levels of an ecosystemecosystem from producers to consumers from producers to consumers

Food ChainFood Chain A simple model that scientists use to show how A simple model that scientists use to show how

matter and energy move through an ecosystemmatter and energy move through an ecosystem Example:Example:

A portion of energy is given off as A portion of energy is given off as HEATHEAT

Trophic LevelsTrophic Levels A feeding step in a food chainA feeding step in a food chain First OrderFirst Order

Eats autotrophsEats autotrophs HerbivoreHerbivore ExampleExample

Second OrderSecond Order Eats first order organismsEats first order organisms CarnivoreCarnivore ExampleExample

Food WebFood Web A model that represents all the possible A model that represents all the possible

feeding relationships at each trophic level feeding relationships at each trophic level in an ecosystemin an ecosystem

More realistic because…More realistic because… Most organisms depend upon more than one Most organisms depend upon more than one

other species for foodother species for food Let’s look at an example of a food web…Let’s look at an example of a food web…

Ecological PyramidsEcological Pyramids Can show how Can show how

energy flows through energy flows through an ecosysteman ecosystem

Base represents:Base represents: Autotrophs (1Autotrophs (1stst trophic trophic

level)level)

Higher levels Higher levels represents:represents: Heterotrophs (2Heterotrophs (2ndnd, 3, 3rdrd, ,

trophic levels)trophic levels)

3 Types of Pyramids3 Types of Pyramids

Shows how much Shows how much energy is transferred energy is transferred from producers to from producers to consumersconsumers

Energy decreases Energy decreases 10% at each level10% at each level

EnergyEnergy

NumbersNumbers

Shows Shows population size population size decreases at decreases at each higher each higher trophic leveltrophic level

Not always Not always truetrue Thousands of Thousands of

insects can eat insects can eat off one treeoff one tree

BiomassBiomass

Represents the Represents the total weight of total weight of living matter at living matter at each trophic each trophic levellevel

Cycles in NatureCycles in Nature

Matter is constantly recycled.Matter is constantly recycled. It is never It is never LOSTLOST!!

The Water CycleThe Water Cycle Life on Earth depends upon Life on Earth depends upon WATERWATER How the cycle works:How the cycle works:

EvaporationEvaporation• Liquid to gas (called water vapor)Liquid to gas (called water vapor)

CondensationCondensation• Water vapor condenses on dust in air + forms cloudsWater vapor condenses on dust in air + forms clouds

PrecipitationPrecipitation• Water falls to ground in form of rain, ice, or snowWater falls to ground in form of rain, ice, or snow

TranspirationTranspiration• Loss of water by plants – puts water vapor into airLoss of water by plants – puts water vapor into air

What is looks like…What is looks like…

The Carbon CycleThe Carbon Cycle CarbonCarbon is an important part of all living things is an important part of all living things

Makes up all molecules of life – Makes up all molecules of life – • carbohydrates, proteins, fats, nucleic acidscarbohydrates, proteins, fats, nucleic acids

Parts of Carbon Cycle:Parts of Carbon Cycle: PhotosynthesisPhotosynthesis

• Autotrophs use COAutotrophs use CO22 from air to make energy-rich compounds from air to make energy-rich compounds RespirationRespiration

• Both autotrophs + heterotrophs use COBoth autotrophs + heterotrophs use CO22 in processes and in processes and release COrelease CO22 back into the evironment back into the evironment

Other ways:Other ways:• Death + decayDeath + decay• Burning of fossil fuelsBurning of fossil fuels• FiresFires

What it looks like…What it looks like…

The Nitrogen CycleThe Nitrogen Cycle Atmospheric NitrogenAtmospheric Nitrogen

Nitrogen makes up 78% of atmosphereNitrogen makes up 78% of atmosphere

Nitrogen-fixing bacteriaNitrogen-fixing bacteria Bacteria found on roots of plants fix nitrogen into Bacteria found on roots of plants fix nitrogen into

different compounds in the soildifferent compounds in the soil

Animal consumptionAnimal consumption Eat plants or other animalsEat plants or other animals Waste materials enter groundWaste materials enter ground Decomposers – put Nitrogen back into atmosphereDecomposers – put Nitrogen back into atmosphere

What it looks like…What it looks like…

The Phosphorus CycleThe Phosphorus Cycle Short termShort term

Plants get P from soilPlants get P from soil Animals eat plants – get PAnimals eat plants – get P When animals die, P gets returned to soilWhen animals die, P gets returned to soil

Long termLong term P enters waterP enters water P gets absorbed into rocksP gets absorbed into rocks Millions of years later, rocks erode, releases P Millions of years later, rocks erode, releases P

back into cycleback into cycle

What it looks like…What it looks like…