Abiotic Factors

And their Effects on the Ecosystem

(c )(6)(A)

The Abiotic Components of Ecosystems

1) Outside energy source1) Outside energy source

2) Physical factors that determine2) Physical factors that determine weather, climateweather, climate

3) Chemicals essential for life3) Chemicals essential for life

Outside Energy Source

PowersPowersphotosynthesisphotosynthesis

Warms earthWarms earth

Powers waterPowers watercyclecycle

Physical factors that Physical factors that determinedetermine

weather, climateweather, climate

HeatHeat

WindWind

PrecipitationPrecipitation

TopographyTopography

HeatHeatHeatHeat

Location Location

Reflection Reflection

Retention Retention

Wind and PrecipitationWind and Precipitation

Uneven heatingUneven heating Ascending, Ascending,

descending air descending air massesmasses

Slide 13Slide 13Slide 13Slide 13Slide 13

Moist surface warmed by sun

Flows toward low pressure,picks up moisture and heat

Warm,dry air

Hot, wetair

Falls, is compressed, warms Rises, expands, cools

Heat releasedradiates to space

LOWPRESSURE

HIGHPRESSURE

Cool, dryair

Condensationand

precipitation

HIGHPRESSURE

HIGHPRESSURE

LOWPRESSURE

LOWPRESSURE

Figure 6-10Page 117

ModifiersModifiers

Rotation of Rotation of the globethe globe

Geologic Geologic featuresfeatures

Rain ShadowsRain Shadows

Chemicals Essential for LifeChemicals Essential for Life

Elements and Elements and compoundscompounds

Recycled Recycled between biotic between biotic and abiotic partsand abiotic parts

Limiting Factor PrincipleLimiting Factor Principle

Too much or too little of any abiotic factor can Too much or too little of any abiotic factor can limit or prevent growth of a population, even if limit or prevent growth of a population, even if all other factors are optimal for that population.all other factors are optimal for that population.

Single factor most over-abundant or deficient in Single factor most over-abundant or deficient in an ecosystem determines presence/absence of an ecosystem determines presence/absence of specific plants/animals.specific plants/animals.

Ecosystem Concepts and ComponentsEcosystem Concepts and Components

Biomes Biomes

Role of climate

Role of climate

Aquatic life zones

Aquatic life zones

BiomesBiomes

Determined primarily by precipitationDetermined primarily by precipitation• Forests (> 75 cm rain per year)Forests (> 75 cm rain per year)• Grasslands (30-75 cm rain per Grasslands (30-75 cm rain per

year)year)• Deserts (< 30 cm rain per year)Deserts (< 30 cm rain per year)

BiomesBiomes

Determined secondarily Determined secondarily by temperature:by temperature:

Type of forest, grassland, Type of forest, grassland, or desert determined by or desert determined by average annual average annual temperaturetemperature

Salinity

Factors affecting soil salinity

Irrigation water quality Fertilizers applied Irrigation regimen and type

of irrigation system

A poorly drained soil might reach a salinity level that is harmful to the plants and to the whole crop. A soil that was not flushed after a previous growing cycle might contain high level of accumulated salts. 

Matter Cycling in EcosystemsMatter Cycling in Ecosystems

Biogeochemical or nutrient cyclesBiogeochemical or nutrient cycles

Hydrologic cycle (H2O)Hydrologic cycle (H2O)

Atmospheric or gaseous cycles (C, N)Atmospheric or gaseous cycles (C, N)

Sedimentary cycles (P, S)Sedimentary cycles (P, S)

Hydrologic (Water) Cycle

Driven by physical forcesDriven by physical forces

The Carbon Cycle

Driven by biological forces:Driven by biological forces:photosynthesis and photosynthesis and respirationrespiration

The Nitrogen Cycle

Driven by biological forces: bacteriaDriven by biological forces: bacteria

Root nodulesRoot noduleson legumeson legumes

CyanobacteriaCyanobacteria

The Phosphorus Cycle

Driven by physical forcesDriven by physical forces

Community ChangeCommunity Change

Ecological succession: gradualreplacement of one kind of community of organisms by another over time; initiated by disturbance

Ecological succession: gradualreplacement of one kind of community of organisms by another over time; initiated by disturbance

Ecological Succession:Communities in Transition - Type #1Ecological Succession:Communities in Transition - Type #1

Primary successionPrimary succession

begins with barren area, no soilbegins with barren area, no soil

Ecological Succession: Communities in Transition - Type #1Ecological Succession: Communities in Transition - Type #1

Slow soil development by weathering,activities of tolerant speciesSlow soil development by weathering,activities of tolerant species

pioneer speciespioneer species

Ecological Succession:Communities in Transition - Type #1Ecological Succession:Communities in Transition - Type #1

Gradual changeover to less tolerantspecies over long periods of timeGradual changeover to less tolerantspecies over long periods of timeequilibrium or successional speciesequilibrium or successional species

Primary Succession

Ecological Succession:Communities in Transition - Type #2Ecological Succession:Communities in Transition - Type #2

Secondary successionSecondary succession

begins with soil already in placebegins with soil already in place

Ecological Succession: Communities in Transition - Type #2Ecological Succession: Communities in Transition - Type #2

Rapid changeover to less tolerantspecies over shorter periods of timeRapid changeover to less tolerantspecies over shorter periods of timerapid because soil already presentrapid because soil already present

Secondary Succession

The End Product

If undisturbed, communities changetoward a relatively stable stageIf undisturbed, communities changetoward a relatively stable stage

- climax community- climax community

- long-term presence if not disturbed- dominated by less-tolerant species- general equilibrium

- long-term presence if not disturbed- dominated by less-tolerant species- general equilibrium