Ecology:Ecology:Parts of an EcosystemParts of an EcosystemPopulation DynamicsPopulation Dynamics

EcologyEcology

What is it?What is it?

•Study of how organisms Study of how organisms INTERACTINTERACT with living and non- with living and non-

living thingsliving things

What will we be looking at?What will we be looking at?

Parts of an ecosystemParts of an ecosystem Things that affect pop’n sizeThings that affect pop’n size Roles and relationships in an ecosystemRoles and relationships in an ecosystem Energy flow in an ecosystemEnergy flow in an ecosystem Importance of biodiversityImportance of biodiversity SuccessionSuccession Human impacts on the environmentHuman impacts on the environment

What makes up an ecosystem?What makes up an ecosystem?• ECOSYSTEMS – BRAIN POP!

!

BIOTIC FACTORSBIOTIC FACTORS• “Bio” means living• Living things in an ecosystem• Can you list the living things

that live in this ecosystem?• Frogs, insects, fish, hawks,

grasses, bacteria, amoeba etc……..

What makes up an ecosystem?What makes up an ecosystem?

• ABIOTIC FACTORSABIOTIC FACTORS• When you put “a” in front of a When you put “a” in front of a

word it negates itword it negates it• Means “non-living” factorsMeans “non-living” factors• Can you list some non-living Can you list some non-living

factors that affect the pond factors that affect the pond ecosystem?ecosystem?• Water, light, temp, acidity, Water, light, temp, acidity,

oxygen and nitrogen levelsoxygen and nitrogen levels

Organization of Life• BIOSPHEREBIOSPHERE

• HABITATHABITAT

• ECOSYSTEMECOSYSTEM

• COMMUNITYCOMMUNITY

• POPULATIONPOPULATION

Decreasing amount of biotic and

abiotic factors

Population Growth Brain Pop Video

What affects pop’n sizes in an What affects pop’n sizes in an ecosystem?ecosystem?

• COMPETITION!COMPETITION!• Struggle for resources among organismsStruggle for resources among organisms• If no competition, pop’ns would grow If no competition, pop’ns would grow

INFINITELY (no limit!)INFINITELY (no limit!)• Competition maintains FINITE (limited) Competition maintains FINITE (limited)

pop’n sizespop’n sizes• Finite popn’s limited by LIMITING Finite popn’s limited by LIMITING

FACTORSFACTORS• CAN BE ABIOTIC OR BIOTICCAN BE ABIOTIC OR BIOTIC

Comparing Finite and Infinite Comparing Finite and Infinite Pop’nsPop’ns

INFINTITE GROWTHINFINTITE GROWTH FINITE GROWTHFINITE GROWTH

What affects pop’n sizes in an What affects pop’n sizes in an ecosystem?ecosystem?

• ABIOTIC LIMITING FACTORSABIOTIC LIMITING FACTORS Amount and intensity of sunlightAmount and intensity of sunlight Amount of waterAmount of water Amount of dissolved oxygen (lakes, rivers, Amount of dissolved oxygen (lakes, rivers,

etc)etc) Acid levelAcid level Temperature rangeTemperature range Minerals available Minerals available

What affects pop’n sizes in an What affects pop’n sizes in an ecosystem?ecosystem?

• BIOTIC LIMITING FACTORSBIOTIC LIMITING FACTORS• Predator/Prey relationshipsPredator/Prey relationships

• Predators limit prey pop’n sizes by Predators limit prey pop’n sizes by eating themeating them

• Prey limit predator pop’n sizes by Prey limit predator pop’n sizes by dying/being killed dying/being killed

• If too many killed, predators starveIf too many killed, predators starve• Adapting (survival of fittest)Adapting (survival of fittest)

What affects pop’n sizes in an What affects pop’n sizes in an ecosystem?ecosystem?

Effects of Predator/Prey Relationship

As you can see, AS PREY POP’N DECREASES, THE PREDATOR’S POP’N DECREASES

What do we call it when a species What do we call it when a species reaches its limit?reaches its limit?

• EVERY pop’n in an ecosystem has a EVERY pop’n in an ecosystem has a CARRYING CARRYING CAPACITY (K)CAPACITY (K)• The # of orgs of a single species an ecosystem The # of orgs of a single species an ecosystem

can can supportsupport• DeterminedDetermined by by bioticbiotic and and abioticabiotic factors factors

• EXEX:: a fox pop’n is affected by how much it a fox pop’n is affected by how much it has to eat (biotic) and also temperature has to eat (biotic) and also temperature (abiotic)(abiotic)

• Once K is reached, pop’n will remain stable Once K is reached, pop’n will remain stable unless major changes in biotic and abiotic unless major changes in biotic and abiotic factorsfactors

Carrying Capacity (K)Carrying Capacity (K)of a Stable Pop’nof a Stable Pop’n

•This graph shows the Carrying Capacity (K) of an organismThis graph shows the Carrying Capacity (K) of an organism•THIS SHOWS A THIS SHOWS A STABLE POP’NSTABLE POP’N

•SLOWLY INCREASING TO K AND THEN SLOWLY INCREASING TO K AND THEN DECREASING ONCE IT HITS K AND BACK UP DECREASING ONCE IT HITS K AND BACK UP AGAINAGAIN