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BIOL 1005 1st Edition Lecture 7 Outline of Last Lecture I. Test IOutline of Current Lecture I. Biological Communities and Species InteractionsII. CommunityIII. Tolerance LimitsIV. AdaptationV. Natural SelectionVI. SpeciationVII. Galapagos FinchesVIII. Ecological NicheIX. The Intensity of the CompetitionX. CompetitionXI. Adaptions the reduce the overlapXII. Law of Competitive ExclusionXIII. Resource PartitioningXIV. Species InteractionsXV. Keystone SpeciesXVI. SymbiosisXVII. Communities in TransitionXVIII. Primary SuccessionXIX. Secondary SuccessionXX. Ecological SuccessionXXI. Introduced Species and Community ChangeCurrent LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.I. Biological Communities and Species Interactionso Putting all populations in a community together in an environmentII. Communityo Community – all the interacting populations of an ecosystem o Population – Not an individual or entire species but a group of a species in a given populationIII. Tolerance Limitso Law of Tolerance – set of conditions that as they change the community best adapted to it will change as wellIV. Adaptationso Adapt is used in two ways:- Range of physiological modifications available to individual organisms.- Inheritance of specific genetic traits allowing a species to live in a particular environment. - Population level Explained by process of evolutionV. Natural Selectiono Natural Selection - Members of a population best suited for a particular set of environmental conditions survive and reproduce more successfully than competitors.- Acts on pre-existing genetic diversity.- Limited resources place selective pressures on a population.VI. Speciationo Speciation - Given enough geographical isolation or selective pressure, members of a population become so different from their ancestors that they may be considered an entirely new species.- Alternatively, isolation of population subsets, preventing genetic exchange, can result in branching off of new species that coexist with the parental line.- Ex: Black Bass – largemouth and smallmouth - Small group isolates themselves and changeVII. Galapagos FinchesVIII. Ecological Nicheo Ecological Niche - habitat and function put togethero Habitat - Place or set of environmental conditions where a particular organism lives.o Function - Description of the role a species plays in a biological community, or the total set of environmental factors that determines species distribution.- Generalists : Broad niche- Specialists : Narrow niche- More vulnerable and apt to become extinct IX. The Intensity of the Competitiono Depends on how similar the requirements of the species are o How much the ecological niches overlap o The more similar they are the more they overlap and must compete - Ex – rabbits and mice compete for foodX. Competitiono Interspecific - Competition between members of different species.o Intraspecific - Competition among members of the same species.- Often intense due to same space and nutritional requirements - Can’t get any more similar- Most intenseXI. Adaptions the Reduce the Overlapo Competition exclusion principle o Resource partitioning XII. Law of Competitive Exclusiono Law of Competitive Exclusion - No two species will occupy the same niche and compete for exactly the same resources for an extended period of time.- One will either migrate, become extinct, or partition the resource and utilize a sub-set of the same resource.- Given resource can only be partitioned a finite number of times.- Ex – two different bacteria are put in a beaker and one outcompetes the otherXIII. Resource Partitioningo Share and divide the environmento Limits the food resourcesXIV. Species Interactionso A predator is an organism that feeds directly upon another living organism, whether or not it kills the prey in doing so.- Prey most successfully on slowest, weakest, least fit members of target population.- Reduce competition, population overgrowth, and stimulate natural selection. Co-evolution- Ex – wolves, rabbits, and grassXV. Keystone Specieso Keystone Species - A species or group of species whose impact on its community or ecosystem is much larger and more influential than would be expected from mere abundance.- Often, many species are intricately interconnected so that it is difficult to tell which is the essential component.- If removed, whole system falls apart- Does not have to be a predatorXVI. Symbiosiso Symbiosis - Intimate living together of members of two or more species.- Commensalism: One member benefits while other is neither benefited nor harmed.- Tree and ivy Ivy latches onto tree but gets energy elsewhere - Mutualism: Both members benefit.- Lichens (Fungus and Cyanobacterium)- Shrimp and fish- Parasitism: One member benefits at the expense of other.- Humans and Tapeworms- Mosquitos and Humanso They suck our blood for energyXVII. Communities in Transitiono Ecological Succession- Primary Succession: A community begins to develop on a site previously unoccupied by living organisms.- Starting from scratch Pioneer Species Volcano lava starts new island and the new rock turns into vegetation - Secondary Succession: An existing community is disrupted and a new one subsequently develops at the site.- Knocking the process backwards- Climax community restores itself Cutting down a forest Forest fire Disease- Climax Community: does not change climate and remains best suited for climate- Pioneer CommunityXVIII. Primary SuccessionXIX. Secondary SuccessionXX. Ecological Successiono Ecological Development - Process of environmental modification (facilitation) by organisms.o Climax Community - Community that develops and seemingly resists further change.- Equilibrium Communities (Dis-climax Communities) - Never reach stable climax because they are adapted to periodic disruption.XXI. Introduced Species and Community Changeo If introduced species prey upon or compete more successfully than native populations, the nature of the community may be altered.- Human history littered with examples of introducing exotic species to solve problems caused by previous introductions.- Some are problems and others aren’t - What is there niche?- Some outcompete and others


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