1 Chapter 2 Chapter 2 Principles of Principles of Ecology Ecology 2.1 Organisms and 2.1 Organisms and Their Relationships Their Relationships
Jan 17, 2016
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Chapter 2 Principles of Chapter 2 Principles of EcologyEcology
2.1 Organisms and Their 2.1 Organisms and Their RelationshipsRelationships
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What is ecology?What is ecology?
OikosOikos Greek for “homestead” Greek for “homestead”OlogyOlogy means “study of” means “study of” Scientific study of interactions Scientific study of interactions
among organisms and their among organisms and their environmentenvironment
Reveals relationships among living Reveals relationships among living things (biotic) and nonliving (abiotic) things (biotic) and nonliving (abiotic) parts of the worldparts of the world
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What is ecology?What is ecology?
Uses both quantitative and descriptive Uses both quantitative and descriptive researchresearch
Combines information and techniques Combines information and techniques from many scientific fields:from many scientific fields:– MathematicsMathematics– ChemistryChemistry– PhysicsPhysics– GeologyGeology– And many othersAnd many others
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Aspects of Ecological StudyAspects of Ecological Study Biosphere: portion of Biosphere: portion of
the Earth that the Earth that supports lifesupports life– High in atmosphere to High in atmosphere to
bottom of oceanbottom of ocean– Extends several Extends several
kilometers above the kilometers above the Earth’s surface and Earth’s surface and several kilometers several kilometers below the surface of the below the surface of the ocean ocean
– Comparable to peel of Comparable to peel of an applean apple
– Very diverse climateVery diverse climate
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Living thing affected by:Living thing affected by:
Abiotic factorsAbiotic factors– Air currentsAir currents– TemperatureTemperature– MoistureMoisture– LightLight– Soil compositionSoil composition– TerrainTerrain– And many othersAnd many others
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Living thing affected by:Living thing affected by:
Biotic factorsBiotic factors– Same species for Same species for
protection, protection, competition, food, competition, food, and reproductionand reproduction
– Other species for Other species for all but reproductionall but reproduction
Tree decay
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Levels of Organization in EcologyLevels of Organization in Ecology
Need to study Need to study more than just an more than just an individual to get individual to get the whole storythe whole story
Need to study Need to study relationships or relationships or interactions among interactions among organisms of the organisms of the same and different same and different speciesspecies
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Levels of Organization in EcologyLevels of Organization in Ecology
◊◊BiosphereBiosphere– BiomeBiome
EcosystemEcosystem– CommunityCommunity
PopulationPopulation
- Organism- Organism
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PopulationsPopulations
A group of A group of organisms of one organisms of one species that species that interbreed and live interbreed and live together in the together in the same place at the same place at the same timesame time
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PopulationsPopulations
Compete with each other for food, Compete with each other for food, water, space, light and other water, space, light and other resources in short supplyresources in short supply
How organisms share resources How organisms share resources determines how far apart they live determines how far apart they live and how large a population getsand how large a population gets
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PopulationsPopulations
Some species Some species reduce competition reduce competition by larvae and adult by larvae and adult stages living in stages living in different different environments and environments and using different using different resources as food resources as food (frogs and many (frogs and many insects)insects)
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Individuals Interact within Individuals Interact within CommunitiesCommunities
Community: collection of interacting Community: collection of interacting populations (all the populations at populations (all the populations at one place and time)one place and time)
Change in one population will cause Change in one population will cause change in another populationchange in another population– Small changesSmall changes– Large changesLarge changes
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Interactions among living things Interactions among living things and abiotic factors and abiotic factors
Ecosystem: interaction of populations Ecosystem: interaction of populations in a community and nonliving in a community and nonliving (physical) surroundings(physical) surroundings
Three kinds of ecosystemsThree kinds of ecosystems– Terrestrial (land)Terrestrial (land)– Fresh waterFresh water– Marine: 75% of the earthMarine: 75% of the earth
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Organisms in EcosystemsOrganisms in Ecosystems
Habitat: place where an organism lives its Habitat: place where an organism lives its life (home)life (home)
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Organisms in EcosystemsOrganisms in Ecosystems
Niche: the role and position a species Niche: the role and position a species plays in its environmentplays in its environment– All the interactions with abiotic and All the interactions with abiotic and
biotic factorsbiotic factors– Everything the species doesEverything the species does– How it uses resourcesHow it uses resources– Its jobIts job
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Organisms in EcosystemsOrganisms in Ecosystems
Even though two species occupy the Even though two species occupy the same habitat, they do not occupy the same habitat, they do not occupy the same niche because resources (food, same niche because resources (food, shelter) are used in different waysshelter) are used in different ways
It is an advantage for a species to It is an advantage for a species to occupy a different niche, unique occupy a different niche, unique strategies are important to reduce strategies are important to reduce competitioncompetition
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Organisms in EcosystemsOrganisms in Ecosystems
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SymbiosisSymbiosis
Permanent, close association Permanent, close association between two or more organisms of between two or more organisms of different speciesdifferent species
Three types of symbiosisThree types of symbiosis– CommensalismCommensalism– MutualismMutualism– ParasitismParasitism
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CommensalismCommensalism
One species benefits, other species One species benefits, other species not harmed or benefitednot harmed or benefited
Few examples because further study Few examples because further study usually reveals mutualism or usually reveals mutualism or parasitismparasitism
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CommensalismCommensalism
Cattle egrets follow Cattle egrets follow cattle to feed on cattle to feed on the insects stirred the insects stirred up by the grazing up by the grazing cattle. cattle.
Egret benefits as it Egret benefits as it gets more foodgets more food
Cattle is neither Cattle is neither helped nor harmedhelped nor harmed
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CommensalismCommensalism
Orchids growing on Orchids growing on trees have a home trees have a home and moistureand moisture
Orchids benefit Orchids benefit while the tree is while the tree is not affectednot affected
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MutualismMutualism
Both species benefitBoth species benefit
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MutualismMutualism
A remarkable 3-way A remarkable 3-way mutualism appears to mutualism appears to have evolved between have evolved between
an ant, a butterfly an ant, a butterfly caterpillar, and an acacia caterpillar, and an acacia
in the American in the American southwest. The southwest. The
caterpillars have nectar caterpillars have nectar organs which the ants organs which the ants
drink from, and the drink from, and the acacia tolerates the acacia tolerates the
feeding caterpillars. The feeding caterpillars. The ants appear to provide ants appear to provide
some protection for both some protection for both plant and caterpillar.plant and caterpillar.
Research of Diane Wagner, American Museum of Natural History Southwestern Research Station
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MutualismMutualism
Ants “tending” soybean aphidsAnts “tending” soybean aphids
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ParasitismParasitism
One organism One organism benefits the other benefits the other is harmed but is harmed but usually not killedusually not killed
Ring Worm
Ticks
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Chapter 2 Principles of Chapter 2 Principles of EcologyEcology
2.2 Flow of Energy in an 2.2 Flow of Energy in an EcosystemEcosystem
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How Organisms Obtain EnergyHow Organisms Obtain Energy
Ultimate source of energy is the sunUltimate source of energy is the sun Producers use the sun’s energy to Producers use the sun’s energy to
make foodmake food Consumers eat producers and other Consumers eat producers and other
consumersconsumers
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How Organisms Obtain EnergyHow Organisms Obtain Energy
Autotrophs: “auto” = self; “troph”= Autotrophs: “auto” = self; “troph”= energyenergy– Most are photoautotrophs: organisms Most are photoautotrophs: organisms
that use the sun’s energy to make food that use the sun’s energy to make food in the process of photosynthesis; all in the process of photosynthesis; all have chlorophyllhave chlorophyll
– Some are chemoautotrophs; make food Some are chemoautotrophs; make food by using energy stored in chemical by using energy stored in chemical bonds (some Archaebacteria)bonds (some Archaebacteria)
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PhotoautotrophsPhotoautotrophsCyanobacteria
Algae
Plants
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How Organisms Obtain EnergyHow Organisms Obtain Energy
Heterotrophs: “hetero”= other; Heterotrophs: “hetero”= other; “troph”= energy“troph”= energy– Can’t make food so must feed on other Can’t make food so must feed on other
organismsorganisms– Herbivores: only eat autotrophsHerbivores: only eat autotrophs– Carnivores: only eat other heterotrophsCarnivores: only eat other heterotrophs– Omnivore: eat both autotrophs and Omnivore: eat both autotrophs and
heterotrophsheterotrophs
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How Organisms Obtain EnergyHow Organisms Obtain Energy
Heterotrophs: “hetero”= other; Heterotrophs: “hetero”= other; “troph”= energy, cont.“troph”= energy, cont.– Scavengers: feed on dead (carrion and Scavengers: feed on dead (carrion and
refuse)refuse)– Decomposers: breakdown and absorb Decomposers: breakdown and absorb
nutrients from dead organisms (fungi, nutrients from dead organisms (fungi, protozoans, many bacteria)protozoans, many bacteria)
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HeterotrophsHeterotrophsCarnivoreCarnivore
HerbivoreHerbivore
DecomposerDecomposer
ScavengerScavenger
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How Organisms Obtain EnergyHow Organisms Obtain Energy
DetritivoresDetritivores– Eat fragments of Eat fragments of
dead matter in an dead matter in an ecosystem, and ecosystem, and return nutrients to return nutrients to the soil, air, and the soil, air, and water where the water where the nutrients can be nutrients can be reused by reused by organisms.organisms.
– Also considered Also considered heterotrophsheterotrophs
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Matter and Energy FlowMatter and Energy Flow
Food Chains: simple model to show energy Food Chains: simple model to show energy flow in an ecosystem; one possible routeflow in an ecosystem; one possible route
Food web: several interconnected food Food web: several interconnected food chainschains– shows that an organism occupies more than shows that an organism occupies more than
one trophic levelone trophic level– Expresses more possible feeding relationships Expresses more possible feeding relationships
at each trophic levelat each trophic level– More realistic than a food chainMore realistic than a food chain
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Food ChainFood Chain
Arrows indicate direction energy Arrows indicate direction energy flowsflows
Usually 3 to 5 trophic (energy) levelsUsually 3 to 5 trophic (energy) levels On average only 10% of energy is On average only 10% of energy is
transferred to next trophic leveltransferred to next trophic level– Most energy is lost as heatMost energy is lost as heat– Also lost as urine, feces and otherAlso lost as urine, feces and other
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Food ChainFood Chain
Top CarnivoreTop Carnivore
CarnivoreCarnivore
OmnivoreOmnivore
HerbivoreHerbivore
ProducerProducer
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Food WebFood Web
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Food WebFood Web
Trophic level is one step in a food Trophic level is one step in a food chainchain
Organisms can occupy more than Organisms can occupy more than one trophic levelone trophic level
Important part of organism’s niche is Important part of organism’s niche is how it obtains energyhow it obtains energy
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Energy and Trophic LevelsEnergy and Trophic Levels
Energy PyramidEnergy Pyramid
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Energy PyramidsEnergy Pyramids
Pyramid of NumbersPyramid of Numbers– Count the number of Count the number of
organisms at each organisms at each levellevel
– Numbers decrease as Numbers decrease as move up the pyramidmove up the pyramid
– Not always reveals Not always reveals true relationship as true relationship as one tree (producer) one tree (producer) could support 50,000 could support 50,000 insects (herbivore)insects (herbivore)
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Energy PyramidsEnergy Pyramids
Pyramid of BiomassPyramid of Biomass– Use dry weight of Use dry weight of
organisms at each organisms at each levellevel
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Energy PyramidsEnergy Pyramids
Pyramid of NumbersPyramid of Numbers Pyramid of BiomassPyramid of Biomass
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Chapter 2 Principles of Chapter 2 Principles of EcologyEcology
2.3 Cycling of Matter2.3 Cycling of Matter
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Cycles in NatureCycles in Nature
Energy flows, nutrients cycleEnergy flows, nutrients cycle Atoms of carbon, nitrogen and other Atoms of carbon, nitrogen and other
elements in your body today made up the elements in your body today made up the bodies of other organismsbodies of other organisms
Matter including nutrients are constantly Matter including nutrients are constantly recycledrecycled
The cycling of nutrients in the biosphere The cycling of nutrients in the biosphere involves both matter in living organisms involves both matter in living organisms and physical processes found in the and physical processes found in the environment such as weathering.environment such as weathering.
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Nitrogen CycleNitrogen Cycle
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Phosphorus CyclePhosphorus Cycle
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