ECOLOGYECOLOGY

EcologyEcology

• The study of organisms and their The study of organisms and their interactions with the environmentinteractions with the environment

• The The biospherebiosphere is all the land, water is all the land, water and air in which organisms live.and air in which organisms live.

• All the living parts of an environment All the living parts of an environment are called are called biotic factorsbiotic factors. The . The nonliving parts are called nonliving parts are called abiotic abiotic factors factors (ex: water, light, etc.)(ex: water, light, etc.)

Levels of Organization Levels of Organization in the Biospherein the Biosphere

• Population:Population: consists of all the consists of all the members of a single species that live members of a single species that live in one areain one area

• Community:Community: all populations that live all populations that live and interact in one environmentand interact in one environment

• Ecosystem:Ecosystem: community + abiotic community + abiotic factors; ex: forest, desert, ocean factors; ex: forest, desert, ocean

CyclesCycles

• Matter is recycled within and Matter is recycled within and between ecosystemsbetween ecosystems

• Biogeochemical cyclesBiogeochemical cycles show how show how matter cycles through the biospherematter cycles through the biosphere

• There are 4 types of cycles:There are 4 types of cycles:– Water cycle– Carbon cycle– Nitrogen cycle– Phosphorous cycle

Some TermsSome Terms

• Habitat:Habitat: type of environment in type of environment in which a particular species liveswhich a particular species lives

• Niche:Niche: full range of physical and full range of physical and biological conditions in which an biological conditions in which an organism lives and the way in which organism lives and the way in which the organism uses those conditionsthe organism uses those conditions

• Biodiversity:Biodiversity: the variety of life--the the variety of life--the different plants, animals and micro-different plants, animals and micro-organisms--and the ecosystems of organisms--and the ecosystems of which they are a partwhich they are a part

Food SynthesisFood Synthesis

• Photosynthesis: Photosynthesis: use of light energy use of light energy to make food; process used by to make food; process used by plants, algae and some bacteriaplants, algae and some bacteria

• Chemosynthesis:Chemosynthesis: use of chemical use of chemical energy to make food; process used energy to make food; process used by some bacteriaby some bacteria

RememberRemember

• Autotrophs:Autotrophs: use light energy to use light energy to make their own food; also called make their own food; also called producers

• Heterotrophs:Heterotrophs: can’t make their own can’t make their own food; also called food; also called consumers

Types of HeterotrophsTypes of Heterotrophs

• Herbivores:Herbivores: eat plants eat plants

• Carnivores: Carnivores: eat animalseat animals

• Omnivores: Omnivores: eat both plants and eat both plants and animalsanimals

• Decomposers: Decomposers: break down organic break down organic mattermatter

• Scavengers:Scavengers: eat tissues of dead eat tissues of dead animalsanimals

Community InteractionsCommunity Interactions

• Competition:Competition: organisms attempt to organisms attempt to use an ecological resource in the use an ecological resource in the same place at the same timesame place at the same time

• Symbiosis:Symbiosis: any relationship in which any relationship in which 2 species live closely together2 species live closely together

• Predation:Predation: interaction in which one interaction in which one organism (organism (predator) captures and ) captures and feeds on another organism (feeds on another organism (prey))

Types of Symbiotic Types of Symbiotic RelationshipsRelationships

• Mutualism:Mutualism: both organisms benefit both organisms benefit

• Parasitism:Parasitism: one organism benefits one organism benefits while the other is harmedwhile the other is harmed

• Commensalism:Commensalism: one organism one organism benefits while the other is neither benefits while the other is neither harmed nor benefited harmed nor benefited

Food ChainsFood Chains

• A A food chainfood chain models the flow of models the flow of energy through organisms in a energy through organisms in a communitycommunity

• The flow is in one directionThe flow is in one direction

• Each step in the transfer of energy Each step in the transfer of energy and matter in an ecological and matter in an ecological community is called a community is called a trophic leveltrophic level

• Only 10% of the energy from one level Only 10% of the energy from one level is transferred to the level above itis transferred to the level above it

FOOD

CHAIN

Food WebFood Web

• Shows how food chains are Shows how food chains are connectedconnected

Ecological PyramidsEcological Pyramids

• Show the relationship between Show the relationship between producers and consumers at the producers and consumers at the trophic levels in an ecosystemtrophic levels in an ecosystem

• There are 3 types of pyramids:There are 3 types of pyramids:– Energy Pyramid– Biomass Pyramid– Pyramid of Numbers

Growth RateGrowth Rate

• Growth rate = change in the number of Growth rate = change in the number of individuals divided by the time periodindividuals divided by the time period

• Factors that play a role in growth Factors that play a role in growth rate:rate:– Birth rateBirth rate– Immigration—movement of individuals Immigration—movement of individuals

into an areainto an area– Emigration—movement of individuals out Emigration—movement of individuals out

of an areaof an area– Death rateDeath rate

Exponential GrowthExponential Growth• Occurs when individuals Occurs when individuals

in a population in a population reproduce at a constant reproduce at a constant raterate

• Under ideal conditions Under ideal conditions with unlimited with unlimited resources, a population resources, a population will grow exponentiallywill grow exponentially

• As resources become As resources become less available, the less available, the growth of a population growth of a population slows or stopsslows or stops

The red bracket shows the area of the graph that represents exponential growth.

Carrying CapacityCarrying Capacity• The number of individuals The number of individuals

in a population that an in a population that an environment can support environment can support over a relatively long over a relatively long period of timeperiod of time

• Determined by Determined by limiting limiting factorsfactors

• Limiting factors are biotic Limiting factors are biotic and abiotic resources in and abiotic resources in the environment that limit the environment that limit the size of a populationthe size of a population

The red bracket shows the area of the graph that represents the carrying capacity.

Density-Dependent Limiting Density-Dependent Limiting FactorsFactors

• Factors that become limiting only Factors that become limiting only when the population is largewhen the population is large

• They include:They include:– Living spaceLiving space– DiseaseDisease– CompetitionCompetition– PredationPredation

Density-Independent Limiting Density-Independent Limiting FactorsFactors

• Factors that affect all populations in Factors that affect all populations in the same way, regardless of their the same way, regardless of their sizesize

• They include:They include:– WeatherWeather– Seasonal cyclesSeasonal cycles– Natural disastersNatural disasters

Ecological SuccessionEcological Succession

• As an ecosystem changes, older As an ecosystem changes, older inhabitants gradually die out and new inhabitants gradually die out and new organisms move inorganisms move in

• This series of predictable changes that This series of predictable changes that occurs in a community over time is called occurs in a community over time is called ecological successionecological succession

• There are 2 types:There are 2 types:– Primary successionPrimary succession– Secondary successionSecondary succession

Primary SuccessionPrimary Succession• Occurs where no soil exists Occurs where no soil exists

• Ex: occurs on surfaces formed by Ex: occurs on surfaces formed by volcanic eruptions or on bare rock volcanic eruptions or on bare rock exposed when glaciers meltexposed when glaciers melt

Primary SuccessionPrimary Succession

Secondary SuccessionSecondary Succession

• Occurs when a disturbance of some Occurs when a disturbance of some kind changes an existing community kind changes an existing community without removing the soilwithout removing the soil

• Ex: wildfires burn woodlands or field Ex: wildfires burn woodlands or field is cleared for farming and then is cleared for farming and then abandonedabandoned

Secondary SuccessionSecondary Succession

Biological MagnificationBiological Magnification

• Buildup of a pollutant in organisms Buildup of a pollutant in organisms at higher trophic levels in a food at higher trophic levels in a food chainchain

ppm=parts per million