Ecosystem

Chapter 55: Ecosystems and Restoration EcologyEssential Knowledge2.a.1 All living systems require constant input of free energy (55.2 & 55.3).2.d.1 All biological systems from cells and organisms to populations, communities, and ecosystems are affected by complex biotic and abiotic interactions involving exchange of matter and free energy (55.1 55.4)4.a.6 Interactions among living systems and with their environment result in the movement of matter and energy (55.1, 55.3, 55.4, 55.5).

EcosystemAll the organisms and abiotic factors in a community.Ecosystem Studies1. Energy Flow the movement of energy through trophic levels.2. Chemical Cycling the movement of matter from one part of the ecosystem to another.Trophic LevelsDivision of an ecosystem based on the source of nutrition (energy).Trophic Levels1. Primary Producers2. Primary Consumers3. Secondary Consumers4. Detritivores

Primary ProducersUsually plants, capture energy and store it in chemical bonds.Are the source of the energy available to an ecosystem.

Primary ConsumersOrganisms that feed on the producers.Ex: Herbivores

Secondary ConsumersOrganisms that feed on the Primary Consumers.Ex: Carnivores

DetritivoresGet their energy from the organic waste produced by all levels.Ex: bacteria and fungiFood ChainLinear pathway of who eats who in an ecosystem.

Food WebsNetwork showing all the feeding relationships in an ecosystem.

Primary ProductivityThe rate at which light energy is captured by autotrophs or primary producers.

Primary ProductivityNPP = GPP - RsNPP = Net Primary ProductivityGPP = Gross Primary ProductivityRs = RespirationAvailable EnergyDaily - 1022 joules of solar radiation.1% - captured by Ps.About 170 billion tons of organic matter is created each year.Primary Producers50 - 90% of GPP is lost to Rs by the primary producers.NPP = 10 - 50%Animals - use only NPP, which limits the food webs.Limiting FactorsMaterial or nutrient that is not present in sufficient quantity for the primary producers.Ex: N, P, K, Mg Light, CO2Energy TransfersNot 100% efficient.Averages 10% with each tropic level changeWhy?Second law of thermodynamics.Waste.Materials that cant be digested etc.Question ?Why do most ecosystems have only 3 - 4 trophic levels?There isnt enough energy passed up through the food web to support more levels.ImplicationsThere has to be fewer high level consumers in a food web.The higher level consumers usually need a large geographical area.PyramidsGraphical representation of relationships in ecosystems.Ex:1. Productivity2. Biomass3. Numbers

QuestionWhat would a numbers pyramid look like in an Indiana forest?Inverted pyramid. Few producers (trees) and many primary consumers.What would a Biomass pyramid look like in an Indiana forest?Pyramidal in shape.

Chemical CyclingMatter is recycled through ecosystems.Ex: Biogeochemical CyclesMatter Reservoirs1. Organic Materials2. Inorganic MaterialsAvailable UnavailableRepresentative Biogechemical CyclesWaterCarbonNitrogenKnow one or more of these cycles for various multiple choice questions and possibly a short answer questionWater cycle

Carbon cycle

Nitrogen cycle

Energy vs MatterEnergy - flows through ecosystems and is mostly lost as heat.Matter - cycles in ecosystems.Question ?What is Man's influence on Ecosystems ?Humans have had many negative impacts.Biological MagnificationThe concentration of toxins in successive levels of a food web.Ex: DDT Heavy metals -Hg, Cd, Pb

CausesNot broken down by digestion/decomposition.Lipophilic.Concentrates and effects the upper levels of the food web.DDT Example

Greenhouse EffectsThe trapping of heat by the Earth's atmosphere. (CO2, H2O etc.).Causes:Warms Earths temperaturesGlobal warming

Carbon Dioxide LevelsPrior 1850 - 274 ppm 1958 - 316 ppm 1992 - 351 ppmPoint: the levels of CO2 are rising. Cause? Probably due to humans.Human CO2 Increase CausesIndustrialization.Burning of fossil fuels.Loss of forests.ResultEarth will heat up. Ice caps melt and sea levels will rise.Climate shifts.Increased Ps (?)Exotic SpeciesWhen transplanted species are too successful and upset the ecosystem in new areas.Ex: Starlings Fire Ants CarpInvasive species website

AustraliaHas had many problems with transplanted speciesEx: Rabbits Cacti Foxes Cane toads

SuccessionChanges in species composition over time.

Succession StagesSere: unstable stage usually replaced by another community.Climax: stable stage, self-reproducing.Succession Types1. Primary2. Secondary

Primary SuccessionBuilding a community from a lifeless area.Ex: volcanic islands glaciated areas road cuts

CommentThe first example of primary succession was worked out on the Indiana Dunes.Stages: Open BeachBeach GrassesConifers (Junipers and Pines)OaksBeech-Maple forest (Climax)

Secondary SuccessionWhere a community has been disturbed and the soil is mostly intact.Ex: Cutting down a forestBlow-outs on the DunesSummaryIdentify the trophic levels of ecosystems.Recognize the flow of energy through food chains and food webs.Recognize the calculations used in measuring productivity.Recognize how productivity and energy transfers can be diagramed in pyramid form.Recognize that matter cycles in ecosystems.Identify the concept of Biological Magnification.Recognize several current environmental concerns.