Community Community InteractionsInteractions
AP Biology - 2005AP Biology - 2005
CommunityCommunity
A division of an ecosystem that A division of an ecosystem that describes all of the organisms that describes all of the organisms that live in an arealive in an area
Focuses on interactions within the Focuses on interactions within the communitycommunity
Establishes a niche – a set of Establishes a niche – a set of conditions under which an organism conditions under which an organism existsexists
InteractionsInteractions
Focus on resources available in the communityFocus on resources available in the communityFoodFoodWaterWaterSpaceSpaceMatesMatesNesting sitesNesting sitesHiding placesHiding placesLightLightMacro and micronutrientsMacro and micronutrients
Limiting ResourcesLimiting Resources
There are only so many resources in a There are only so many resources in a community for all of the organismscommunity for all of the organisms
This limits the growth of populations of This limits the growth of populations of organisms within this communityorganisms within this community
It leads to specialized interactions It leads to specialized interactions within the members of this communitywithin the members of this community
( population dynamics)( population dynamics)
InteractionsInteractions
Interspecific – Between different Interspecific – Between different speciesspecies
Intraspecific – Within the same Intraspecific – Within the same speciesspecies
Interaction links and Interaction links and ExamplesExamples
http://eebweb.arizona.edu/Animal_Bhttp://eebweb.arizona.edu/Animal_Behavior/lycaenids/lycaen2.htmehavior/lycaenids/lycaen2.htm
Ecological relations( 1)Ecological relations( 1)
One organism benefits in a One organism benefits in a relationship the other is harmed or is relationship the other is harmed or is eateneaten
Example – predator – prey and parasite Example – predator – prey and parasite = host= host
Rating +/-Rating +/-Lynx and hare – predator and preyLynx and hare – predator and preyMalaria, red blood cell, and human – Malaria, red blood cell, and human –
parasite and hostsparasite and hosts
Cyclic predator-prey relationshipsCyclic predator-prey relationships
ExperimentExperiment
Experiment( con)Experiment( con)
Ecological relations( 2)Ecological relations( 2)
Two organisms compete for the same Two organisms compete for the same resources. This is known as competition.resources. This is known as competition.
Rating -/- or +/-Rating -/- or +/-
ExamplesExamples
Competition for mates – intraspecificCompetition for mates – intraspecific
Competition for space – plants – allelopathyCompetition for space – plants – allelopathy
Competition for nutrients and space – fungi Competition for nutrients and space – fungi and bacteria - antibioticsand bacteria - antibiotics
MutualismMutualism
Both organisms benefitBoth organisms benefit Rating +/+Rating +/+ Zooxanthellae and coral polypZooxanthellae and coral polyp Legumes and RhizobiumLegumes and Rhizobium Leaf cutter ant and fungal gardenLeaf cutter ant and fungal garden Ant and acaciaAnt and acacia
Leaf cutter ants and fungal gardensLeaf cutter ants and fungal gardenshttp://www.blueboard.com/leafcutters/what.hthttp://www.blueboard.com/leafcutters/what.ht
mm
http://cas.bellarmine.edu/tietjen/Ecology/fungus.htm
Ant and the AcaciaAnt and the Acacia
CommensalismCommensalism
One organism benefits – the other is One organism benefits – the other is neither harmed or benefitsneither harmed or benefits
+/0+/0 Examples – Pinnepidia crab and Examples – Pinnepidia crab and
tube wormtube worm
AmensalismAmensalism
Animals can have a negative effect Animals can have a negative effect on the environmenton the environment
0/-0/- Animals trampling the grass on the Animals trampling the grass on the
way to the water holeway to the water hole
ContradictionsContradictions
Not all organisms fit the description Not all organisms fit the description exactlyexactly
The definition for symbiosis is The definition for symbiosis is changing to include only those changing to include only those interactions between organisms of interactions between organisms of two different species whose two different species whose metabolism is altered by the metabolism is altered by the interactioninteraction
Competition- InterspecificCompetition- Interspecific
Allelopathy – How plants guard their Allelopathy – How plants guard their space by releasing molecules into space by releasing molecules into the environment that deters other the environment that deters other plants from occupying their spaceplants from occupying their space
http://www.units.muohio.edu/dragohttp://www.units.muohio.edu/dragonfly/itc/index.htmlxnfly/itc/index.htmlx
Intraspecific CompetitionIntraspecific Competition
Interspecific CompetitionInterspecific Competition
Barnacle species Barnacle species on a rocky shoreon a rocky shore
Establishes Establishes zonation of zonation of organismsorganisms
Niche determined Niche determined by ability to by ability to barnacles to barnacles to tolerate tolerate dehydrationdehydration
Competition may restrict species’ ranges.Competition may restrict species’ ranges. Two species of barnacles live on North Atlantic Two species of barnacles live on North Atlantic
seashores, but as adults, one species lives seashores, but as adults, one species lives higher in the intertidal zone than the other, with higher in the intertidal zone than the other, with little overlap between the two (a phenomenon little overlap between the two (a phenomenon called intertidal zonation).called intertidal zonation).
If one of the species is removed experimentally, If one of the species is removed experimentally, the vertical range of the other species becomes the vertical range of the other species becomes greater.greater.
The higher-zone barnacle outcompetes the The higher-zone barnacle outcompetes the other because it is more hardy when exposed to other because it is more hardy when exposed to air; in the lower zone, the other barnacle is able air; in the lower zone, the other barnacle is able to smother or crush higher-zone intruders.to smother or crush higher-zone intruders.
Barnacle CompetitionBarnacle Competition
Batesian MimicryBatesian Mimicry
Two different species Two different species resemble each other. resemble each other. One is unpalatable. One is unpalatable. The palatable The palatable receives the benefit receives the benefit of birds not wishing to of birds not wishing to eat it because they eat it because they have eaten the have eaten the unpalatable one with unpalatable one with bad results.bad results.
It pays to advertiseIt pays to advertise
Keystone SpeciesKeystone Species
http://www.prairiedogs.orhttp://www.prairiedogs.org/keystone.htmlg/keystone.html
A keystone species is a A keystone species is a species whose very species whose very presence contributes to a presence contributes to a diversity of life and whose diversity of life and whose extinction would extinction would consequently lead to the consequently lead to the extinction of other forms extinction of other forms of life. Keystone species of life. Keystone species help to support the help to support the ecosystem (entire ecosystem (entire community of life) of community of life) of which they are a part. which they are a part.
SuccessionSuccession
Succession begin when an area is Succession begin when an area is made partially or completely devoid made partially or completely devoid of vegetation because of a of vegetation because of a disturbancedisturbance. Some common . Some common mechanisms of disturbance are fires, mechanisms of disturbance are fires, wind storms, volcanic eruptions, wind storms, volcanic eruptions, logging, climate change, severe logging, climate change, severe flooding, disease, and pest flooding, disease, and pest infestation. infestation.
Plant SuccessionPlant Succession
Succession in a Glacial Succession in a Glacial MoraineMoraine
Degradative successionDegradative succession
The dead body of an organism is The dead body of an organism is reduced to basic molecules by reduced to basic molecules by decomposersdecomposers
Plants may produce litterPlants may produce litter Deciduous trees may produce layer Deciduous trees may produce layer
of litter - compostof litter - compost
CoevolutionCoevolution
The changes in one species may The changes in one species may affect the changes in another affect the changes in another species over timespecies over time
Adaptations may occurAdaptations may occur The organisms can develop a close The organisms can develop a close
associationassociation Pollinators and flowers a key Pollinators and flowers a key
example of coevolutionexample of coevolution
Yucca MothYucca Moth
http://waynesword.palomar.edu/ww0902a.htm
Yucca and mothYucca and moth
Female yucca moths only lay their Female yucca moths only lay their eggs in the ovules of yucca flowers. A eggs in the ovules of yucca flowers. A female Tegeticula( Yucca moth) lays female Tegeticula( Yucca moth) lays no more than 5 eggs in the ovules.no more than 5 eggs in the ovules.
After she has laid the eggs she After she has laid the eggs she scrapes the pollen from the flower’s scrapes the pollen from the flower’s anthers and flies to another Yucca anthers and flies to another Yucca where she transfers the pollen and where she transfers the pollen and lays 5 more eggslays 5 more eggs
Island BiogeographyIsland Biogeography
Immigration of mainland species to island – Immigration of mainland species to island – birds flying – other animals and plants and birds flying – other animals and plants and animals drifting on trees or floating on rafts animals drifting on trees or floating on rafts of vegetation in the currents in the oceanof vegetation in the currents in the ocean
( new plants and animals) Seeds also carried ( new plants and animals) Seeds also carried by birdsby birds
Isolation of species after immigrationIsolation of species after immigration Novel adaptationsNovel adaptations New species develop – allopatric speciationNew species develop – allopatric speciation New genetic speciesNew genetic species
GalapagosGalapagos
Darwin’s finches and the Darwin’s finches and the Galapagos IslandsGalapagos Islands
http://www.rit.edu/~rhrsbi/Galapagohttp://www.rit.edu/~rhrsbi/GalapagosPages/DarwinFinch.htmlsPages/DarwinFinch.html
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