ZNOTES.ORGUPDATED TO 2019-21 SYLLABUSCAIE A2 LEVELSUMMARIZED NOTES ON THE THEORY SYLLABUSCAIE A2 LEVEL BIOLOGY (9700)Quadrat1.Biodiversity·Mark and releaseSimpson's Index of BiodiversityThe importance of random sampling is that a habitat may be1.1.Termstoo large for actual counting so a sample is quick and gives arepresentation of the whole habitat.Species:a group of organisms with similar morphologicaland physiological features,which can interbreed to1.5.Random Samplingfrom other species.Ecosystem:a relatively self-contained,interactingUsed when area looks uniform or there's no clear pattern ofcommunity of organisms,and the environment in whichthe way species are distributedthey live and with which they interact.Consists of bioticQuadrat sampling:and abiotic partsDecide size of quadrat and number of samplesNiche:is the role of an organism in an ecosystem (it is·Mark a specific areahow an organism fits into the ecosystem).Samples are taken randomly eg by using random numbergenerator to give coordinates of sampling points in the1.2.Biodiversityarea to avoid any bias and increase accuracy of estimateBiodiversity:The variety of species in an area along with theirvariation within species and the genetic diversity between1m2quadratthem.The three levels of diversity:Variation in ecosystems or habitatsNumber of different species in the ecosystem andtheir relative abundanceGenetic variation within each speciesUses of maintaining biodiversity:1mMaintains stability of ecosystem;preventing extinction100cmMaintains large gene pool(geneticvariation)Ecosystems provide 'services'for humansSpecies can be source of new medicinesResource such as food and woodLeisure for humans to see in zoos;ecotourism·Climate stability1.3.Genetic Diversitycoordinates1m7,4100cmIs the diversity of the alleles within the genes in thegenome of a single speciesA species can all have the same genes,but differentNote:usually used with species that are stationaryalleles for those genes.Genetic diversity is assessed by2 ways to use your results:finding proportion of genes with different alleles and howSpecies frequency:is the measure of the chance of amany alleles there are per gene.particular species being found in any one quadrant.1.4.Species DiversityNo.of Appearance,×100No.of QuadratsThe number of species in a community is known asSpecies density:is a measure of how many individualsspecies richnessthere are per unit area.Species diversity takes species richness into account,butalso includes evenness of abundance of each speciesTotal Area of All QuadratsIn species diversity there are two points that need to beWhen unable to count,use percentage coverfound:distribution and abundance of species.To do this we use means of Random sampling such as:1.Divide eg 100 x 100 cm quadrat to 100 small squaresCAIE A2 LEVEL BIOLOGY (9700)2.Decide approx.what area inside quadrat isoccupied by each speciesSample Kite ChartobservedAlternatively,use the Braun-Blanquet abundancescale.eMark-release and recapture:BirchUsed with mobile animalsAs many individuals possible are caughtEach individual is marked in a way that would notaffect its chance of survival or reproductionMetresThe marked individuals are counted and returned toShoretheir habitat to mix randomlyAfter enough time elapses for mixing to take place,capture another sampleNumber of marked and unmarked counted and used1.7.Correlationto calculate estimate of populationCorrelation coefficient(r):determine whether there is a linearm*2relationship and its strength(ie how close the points are tothe line)N=population estimaten=number of marked individuals releasedn2=total number of individuals(both marked andunmarked)capturedm2 number of marked individuals recaptured1.6.Systematic SamplingUsed to determine species distribution in areas whereconditions such as altitude,soil moisture content,pH orexposure to light intensity variesUsing transacts:to detect changes in community compositionalong a line across one or more habitats.XXLine transectONegative Correlation0No CorrelationThe number of organisms found at regularAssume the null hypothesis is true:there is no correlationpoints along a line are noted.between the two samplesCreate a scatter graph to see if there's a correlation betweenthe abundance of 2 speciesPearson's linear correlation·Belt transectThe abundance of organisms within quadratssee this if the graph does not appear skewed or hasplaced at regular intervalsobvious outliersMust have linear correlationThe two variables can be on either axisQuantitate data as measurements or countsExy-nzyDrawing a kite diagramr=Find the highest value from the table e.g.6 in this casen sample size(number of observations)Give each species 6 spaces ony axisDraw a straight line of 0 through the middley=number of species x,number of species yDivide the number you are plotting by two,plot it above,y=meanand below the line (from 0)sz,sy=standard deviation of x andy