University f Tennessee, Knxville Trace: Tennessee Research and Creative Exchange University f Tennessee Hnrs Thesis Prjects University f Tennessee Hnrs Prgram 5-2004 Cmpetitin and Invasin in a Micrcsmic Setting Austin Ryce Faulkner University f Tennessee - Knxville Fllw this and additinal wrks at: http://trace.tennessee.edu/utk_chanhnprj Recmmended Citatin Faulkner, Austin Ryce, "Cmpetitin and Invasin in a Micrcsmic Setting" (2004). University f Tennessee Hnrs Thesis Prjects. http://trace.tennessee.edu/utk_chanhnprj/735 This is brught t yu fr free and pen access by the University f Tennessee Hnrs Prgram at Trace: Tennessee Research and Creative Exchange. It has been accepted fr inclusin in University f Tennessee Hnrs Thesis Prjects by an authrized administratr f Trace: Tennessee Research and Creative Exchange. Fr mre infrmatin, please cntact trace@utk.edu.
UNIVERSITY HONORS PROGR~'1 SENIOR PROJECT - APPROVAL Name: _c.a.u.u'd"s.li-bl..!.!'.f\'-l..-...!.h...!:::'\l.:u:",,:,\ k:-f\:...::u=-- Cllege: Arts j SC;~c..e Ei3 Depamnent: Faculty Mentr: _-=0:..:..(.::..----..!i"J~Q.:.:.k:...;...;...:.. W_e..~,-h.. ~ 1"' I have reviewed this cmpleted senir hnrs thesis with this student Jnd certify that it is a prje:;~ ~mmensur:lte whh hnrs level undergraduate research in this tield. SIgned: ~ --3./<.( F.,-</hi,. Faculty Mentr Dace: LL~(?X Cmments (Optina!):
Austin Faulkner Senir Hnrs Prject: Cmpetitin and Invasin in a Micrcsmic Setting Spring 2004
Abstract Students: Austin Faulkner, Bill Hlmes, Jacb Kendrick, Jeff Lwder, Elizabeth Martin, and Alex Perkins Faculty Spnsrs: Suzanne Lenhart, Luis Grss, Jake Weltzin, and Jim Drake Abstract: Single species experiments with tw species frm genera Clpidium and Paramecium, and analysis f data were cmpleted t estimate grwth rates and carrying capacities. The underlying mdel fr each species is a differential equatin with lgistic grwth. Experimental data was used t estimate carrying capacity (K) and grwth rate (r) f the tw species. Next, the tw species were grwn in cmpetitin; that data was used t determine cmpetitin cefficients fr the tw species. This data will be used in the next phase f the experiment, which is t include a spatial cmpnent. We are currently in the prcess f determining migratin rates f the tw species; nce the rates have been determined experimentally we will begin the next phase. We hpe t prve that prpagule pressure will affect invasibility f a system that includes migratin.
Intrductin: Fr the past year I have been invlved in an undergraduate research experience. The gal f the research experience has been the study and creatin f Spatial Distributin Mdels f Invasive species; the research is paid fr thrugh a grant prvided by the NSF. The abstract abve, alng with the PwerPint presentatin, details the early stages f ne phase f the research: cmpetitin n a micrcsmic scale. In rder t understand hw invasin affects a system, it is imprtant t understand the effects f cmpetitin between the integrated species. With that in mind, a series f experiments were designed t study cmpetitin between tw micrrganisms: Clpidium striatum and Paramecium Aurelia. I was invlved in the design, creatin, data cllectin, and analysis stages f the experiments. Methds: Clpidium striatum and Paramecium aurelia were chsen as the tw initial species because they have similar life spans, prey slely n bacteria (they will nt eat themselves r each ther), and are easily identifiable. Prject One: The first phase f the experiment invlved independent grwth f the tw species t determine grwth rate (r) and carrying capacity (K) fr each. A multiple replicate system f three densities (ne, five and ten individuals per milliliter in 100 ml jars) and three replicates each was used t reduce errr in the final rates. 0.2 ml samples were taken each day and the individuals present in that sample cunted. Nutrient slutin was used t replace the sample remved frm each jar. Final numbers f each replicate were averaged tgether and used t cmpute (r) and (K) fr the tw species (fr
results, see table 1). Mdels, assuming basic lgistic grwth, were made using the data. This infrmatin was used fr the next set f experiments, cmpetitin. Prject 2: During this stage f experimentatin a fur replicate system was used in rder t further reduce errr. Cultures f Clpidium striatum and Paramecium aurelia were grwn in mnculture (as a cntrl) and cmpetitin with three starting densities: 9:1,5:5 and 1:9 ratis (in individuals per ml) f Clpidium t Paramecium. The bject f this set f experiments was t determine simple cmpetitin cefficients, as well as t determine if prpagule pressure had an effect n species viability. Bth rganisms were grwn and sampled n a daily basis, at apprximately the same time each day. The data was then used t create rdinary differential equatins (ODEs), which were slved and pltted alng a timeline. Results: Analysis f the graphs led t the cnclusin that Clpidium is a better cmpetitr than Paramecium. The cmpetitin cefficients we assigned t the tw rganisms were 1.0 fr Clpidium and 0.5 fr Paramecium, meaning that Clpidium striatum has twice the cmpetitive effects n Paramecium aurelia than it has n itself. In ther wrds, each Clpidium is twice as effective at using resurces, s everyne present in a micrcsm "cunts" as tw Paramecium as far as the Paramecium are cncerned, and tw Paramecium are necessary t give the equivalent effect f ne Clpidium. Due t this fact, Clpidium was always able t ut-cmpete Paramecium, despite the fact that they have a lwer grwth rate and take lnger t reach carrying capacity (See Graphs 1, 2 and 3).
Cntrary t ur hypthesis, prpagule pressure did nt seem t change the final utcme f the cmpetitin; Clpidium always beat Paramecium eventually, with the frmer always driving the latter t extinctin. Alternating the initial densities f the tw species nly seemed t delay the utcme, but was unable t change it. It is pssible that extreme differences in initial density (i.e. ratis f 1000:1 Paramecium t Clpidium) culd change the eventual utcme, but accrding t the specifics f this experiment it seems as if the nly utcme f cmpetitin between these tw species is extinctin f Paramecium aurelia. Table 1: Clpidium 0.02 Paramecium 0.05 Grwth Rate (r) Carrying Capacity (K) 300 individuals per ml 250 individuals per ml Graph 1: 1:9 rati f Clpidium t Paramecium Estimated r (Paramecium): 0.05 Estimated K (Paramecium): 250 Estimated r (Clpidium): 0.02 Estimated K (Clpidium): 300 200 Red = Paramecium Black = COlpidium 150 200 300 400 500 Time in tii:us
Graph 2: 5:5 rati f Clpidium t Paramecium Estimated r (Paramecium): 0.05 Estimated K (Paramecium): 250 Estimated r (Clpidium): 0.02 Estimated K (Clpidium): 300 Red = Paramecium Black = COlpidium 300 II f bdivimals 200 100 100 200 300 400 Time in I-kus 500 Graph 3: 9: 1 rati f Clpidium t Paramecium Estimated r (Paramecium): 0.05 250 Estimated K (Paramecium): 250 Estimated r (Clpidium): 0.02 Estimated K (Clpidium): 300 Red = Paramecium Black = Clpidium 200 #I 01 Dilliduals 150 100 50 Time in HIr.i
Discussin: The initial questin f the experiment was: Hw des prpagule pressure effect invasin? During the curse f the secnd cmpetitin experiment the questin was answered, at least t sme extent: even with ratis f 9: 1, the inferir cmpetitr (Paramecium) is unable t ut-cmpete, r even cexist, with the superir cmpetitr (Clpidium). Whether r nt this situatin wuld hld true with drastically different initial densities has yet t be determined, but future experiments in that directin may still be perfrmed. Thus far my invlvement with this research has given me the pprtunity t d persnal research in a lab setting, and ver the summer I will be able t intrduce a field cmpnent t my research. I will als be attending a natinal cnference spnsred by the Eclgical Sciety f America (ESA) in Prtland, Oregn. Wrking with students in the mathematical field has increased my understanding f mathematical appraches t bilgical prblems as well. I feel that wrking n this prject has helped me t learn mre abut my field f expertise while allwing me t interact with, and cme t better understand, ther appraches.