Exam One Study Guide
Exam One Study Guide BIOL 2335 A
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This 23 page Study Guide was uploaded by Natalie Seman on Monday October 5, 2015. The Study Guide belongs to BIOL 2335 A at Georgia Institute of Technology taught by Dr. Weissburg in Summer 2015. Since its upload, it has received 131 views. For similar materials see General Ecology in Biology at Georgia Institute of Technology.
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Date Created: 10/05/15
Study Guide Ecology Exam One Population Distribution Lesson One What limits the distribution of a group of organisms o Organisms have not dispersedmigrated to find that area dispersal o Organisms cannot tolerate the conditions in that place abiotic o Negatively affected by other organisms in a place biotic I Example gypsy moth Originally found in England introduced to cape cod and rapidly expanded 0 Not limited by their ability to tolerate conditions only limited by dispersal I Example whooping crane Behavior of the animal is reflected by the migration patterns learned by young and never altered despite the possibility of survival in other regions 0 Limitation by dispersal migration I Example Plants Abiotic limitations most affect plants due to survival of seedlings in temphumidity I Example ground dove In location one three species occupy separate habitats Location two no species three so species one can expand 0 Any time a removal of one species allows the integration of another in the first species previous habitat biotic factors are limiting 0 Experiment Logic Chains I Cthamalus example 1st question Can organism survive in the habitat in question test dispersal first 0 Yes dispersal is responsible o No Can organism survive when protected from other organisms Test biotic interaction next I Yes Biotic interaction limitation I No limitation by abiotic forces Lesson Two Distribution within a Population Active Dispersal 0 Initial decisions based on abiotic conditions then modified based on abiotic factors Passive Dispersal windocean current 0 Initial dispersal is random but can be modified post dispersal processes by mortality based on environmental interactions or biotic interactions Random Distribution Uniform Distribution Clumped Scale physical and biological o X axis distance 0 Y axis environmental propertyresource I Determines where a species can be found within a habitat Within a range of space in unit x there are distributions and variations to an infinitely smaller unit y 0 Scale of variation x or y units of a landscape 0 Scale of organism units that determine If scale of organism gt scale of variation 0 The scale of variation will be leveled out I Uniform distribution If scale of organism lt scale of variation 0 The distribution of individuals will have a relationship Population Growth Lesson One Changes in Pop Size NumberofindividualsN 0 Function of food predator temperature etc 0 Will affect all biotic and abiotic factors 0 Populations that breed continuously with overlapping generations I Dndt BNDN BDN rN BD birthsdeaths per individual per time r instantaneous rate of natural increase 0 r BD I NtN0equotrt N0pop size at t0 Ntpop size at t o Populations with discreet nonoverlapping generations I Nt NoYquott Y average number of progeny born to an individual alive at the beginning of that generation 0 Finite rate of natural increase 0 T is whole number increments Lesson Two Regulation of Population Growth The growth models of lesson one has no constraints DensityDependent regulation Biotic 0 Strength of the biotic interaction is dependent on population density I Competition 1 nterspecific competition between species 2 Intraspecific competition between individuals of same species I Predation Where prey are limited by density of predators and vise versa I Paratisism Interspecific competition 0 O 0 Limiting resource must be shared by both species Low levels of limiting resources amplify the effect of competition Interference direct competition I one species prevents another from accessing a resource Exploitive indirect competition I Consume a resource more efficiently or at a higher rate than another I Do not affect the other species ability to access the resource Taxonomic relationships are not required only closeness of resource requirement Intraspecific competition 0 K is the carrying capacity I Represents point where limiting resource is just enough for the number of individuals I As N approaches K BD approaches 0 Either b decreases or d increases I Dndt is positive when N ltK slows as N approaches K is 0 when NK and is negative when N gtK o Dndt rN KNK logistic equation I Peak at K2 where dndt is maximal I Where dndt is zero NtK Dndt as a function of Mt I If N O the equation is the unaltered growth model I NK dndtO Exponential Growth Logistic Growth Carrying capacity Population size Population suze Time Time I I Logistic Equation must be tested to prove that it is a product of competition Density Independent Regulation 0 Produces fluctuating patterns but experimental proof is always necessary Lesson Three Life Table Analysis Since r depends on B and D it is impractical for most populations Life table 0 Summarize age specific bd to calculate r 0 Tracks a cohort and accounts for bd at specific ages and extrapolate to entire population I Ex population of rabbits at tim t0 6 new baby rabbits cohort from x0 x1 two rabbits die from x1 x2 two rabbits are born one old rabbit dies from x1 x2 six are born all old die Age x Lx survivorship Mx Lx mx X lx mx Alive fecundity 0 6 1 0 0 0 1 4 67 5 33 33 2 3 5 2 1 2 survivorship lx proportion at age xnumber at t0 fecunditymx avg progeny born to an individual alive at beginning at time x 0 ex from x1 to x2 we have 4 rabbits that produce 2 individuals from x1 to x2 calculate r o the sum of xlxmx is AWR o the sum of lxmx is R0 0 T AWRR0 I Generation time o LogR0Tr Lx survivorship 0 Type 1 I High survivorship in early life and more deaths with age mammals 0 Type 2 I Constant survivorship v fecundity graph 0 Type 3 I Survivorship declines drastically very early and then becomes even 100 10 number of survivors log scale 0 age in relative units 0 2011 Encyclopaedia Britannica Inc Lesson JIT Population Growth Overview It is possible to have density dependent competition with a curve that does not follow the logistic equation 0 What causes a growth curve to be large increases with large decreases I The presence of a time lag o Assumptions of Logistic Equation I No Environmental fluctuations K is constant In reality K fluctuates in response to changing environment I Responses are instantaneous In reality there are time lags I Competition strength increases linearly with density In reality the strength might not be constant Reality The logistic equation actually can display a range of behaviors depending on the strength of competition and growth rate g C CI CI 3 3 a I 0 Stable lim ll circles n E39 O 3 3 81 E Q g 3 Growth rate Monotonic damping 0 Competition increases linearly with density and small growth rate I Logistic Dampened oscillation Stable limit cycles 0 Competition strength increases with density growth rate is higher 0 Converge on K Stable Limit CycleChaos 0 Usually look like abiotic forces are limiting I These patterns are not processes and are not proof of any specific kind of competition without testing natural patterns Competition Harmful to both parties Extending the Logistic Equation to Include Second Species ledt rN1K1 N1 N2al2K1 dNZdt rN2 K2 N2 N1a21K2 o where a is the per capita effect on x by y I is a relative effect of one species on another Where or represents the relative effect of one species on another Suppose the large box represents K1 In this example 4 times as many 52 could fit so each member of 52 is worth 1439h that of 1 0t12 025 1 We could do the same for species 2 using K2 So if a 1 then they are identical in terms of resource use the effects of each species on each other is the same is for each species on itself 2 2 1 39 If a lt 1 then each the species has a smaller relative effect on the other 2 2 species if a gt 1 then each species effects the other more strongly than itself Two Species Competition Where is there no growth change in abundance of a gieven species 0 When dndt O o O K1N1N2a12 0 When there are no individuals in Species 1 we get K1a12 0 When K1 N1 Graphical representation of 2 species competition A ledt rN1 K139N139 N2a12K1 0 0 K1 39 N 39 N2a2 A V V Predict the Outcome of Competition Stable Equilibrium single equilibrium model 0 Solid Line is zero growth I The direction of the arrows between the two lines indicates the point of equilibrium wherein one species outcompetes the other The isoclines describe the outcome of competition and the stability of thl at equilibrium 3 r b Who wins Does the system return to the same state equilibrium stability 2 Unstable Equilibrium multiple equilibrium model crossing lines 0 Stable Equilibrium I If system starts at intersection dndt 0 equilibrium 0 Unstable Equilibrium I If system starts at any point outside intersection any perturbation will result in exclusion of one species by another nyuy H quot nyu2 Cl I Invasion and Persistence Conditions 0 If N2 is at K and species 1 is trying to invade N1O r must be positive for N1 to increase I K1K2 gt a12 o Spl will win when it can invade and Sp2 cannot I K1K2 gt a12 o Sp2 will win when it can invade and Spl cannot I K1K2 gt 1a21 Competition Morphological Divergence Speciation I Competition reduces nice and morphological overlap produces niche differentiation and character displacement o Niche displacement results in character displacement I If the peak of character distribution matches the peak in desirable resource the only limiting factor is the availability of the resource 0 If two species exist together and the peaks in resource and character distribution are not aligned the two species are competing Predation harmful to one party beneficial to another Population Cycles and Density Dependent Predation I Population cycles of predators and prey can be linked o Predators can control and are controlled by prey species I Extreme case predators can cause extinction of prey May cascade to other species not focal pre in community I PredatorPrey Arms race o The predator develops more advance characteristics to enhance predation I Morphology pursuit and capture camoflage Behavior Physiology herbivores o The prey develops more advanced characteristics to evade predation I Morphology escape defense camouflage Behavior Physiologiy toxic plants Ex Moose and Wolf in Isle Royale 0 Coupled population cycling Ex plantherbivore systems 0 Tansy Ragwort invasive plant species 0 Ragwort flea beetle predator of tansy ragwort 0 Community Effects of Predators I Sea urchins can dominate the population but if an otter is introduced that preys on the urchins the community can be greatly altered Presence of a basil resource will lead to more lush habitats o A predator that consumes the basil resource will deplete the basil resource and thus the community if not regulated by its own predator keystone predator Lesson Two Volterra s Model I quotThe proportional rate of increase of the eaten species diminishes as the number of individuals of the eating species increases and the augmentation of the eating species increases with the increase of the eaten I Prey o DndtrNa PN I P predator I a predator s capture ratepreypredator constant not dependent on density I a PN loss due to predation if there are no predators prey population increases exponentially I Predator 0 dPdta fN PqP I fis predator birthsprey eaten I q per capita mortality when predator is at ra any amount of prey will decrease o Assumes I No growth without the prey species Only eats one prey Finite prey population can support an indefinite amount of predators I Environment does not change I Turn these into isoclines by setting dndt O Prey isocline rN o39PN Pro39 Predator isocline of39NquP quo39f A P P ro39 v N T N QO39f The LV model predicts predator prey cycling Lesson Two JIT I Correction to Assumptions 0 quotA is a constant I the prey capture ratepreytime changes with prey number but this is not reflected in the equation 0 quotPrey Threshold will Allow Predators to grow continuously I does not account for reality predators cannot grow infinitely on a finite number of prey I Numerical Response rate of increase of predator response vs prey response 0 More prey will increase the number of predators at a constant rate I Line with constant slope o Interference among predators I A small change in predators will induce a small change in prey but at the number of predators increases the number of prey must increase by a larger value 0 Predators Limited by SomethingBesidesPrey I No matter the density of prey the number of predators does not change 0 The changes between the highest to lowest slope reflects changes in predator efficiency high slope efficient predator low slope inefficient predator Characteristics of more efficient predatorsnumerical response Predators t 2 H I Numerical response xi 1 l gt 39 quot a V1 39 I I OCJ r 39 ll39 a lg Al 0 L 7 B f I quot 8 l I 39 39 l l x 391 5 rs 1m 93 by tail39r39wiyei CV87 9 J N Prey density I Functional Response of predators o quotA is a constant 0 Prey capture rate vs prey density would be a straight line I As prey density increases the prey capture rate decreases An infinite number of prey will have a capture rate limited by time top limit I Lower prey density has a lower prey capture rate Refuges of prey not enough experience being a predator Affects the prey isocline P vs N 0 As prey population sizes decrease it is harder to capture those prey so more predators are necessary to keep the prey population from growing Characteristics of predatorsthe functional response arr v Fumuonal response l lr113 hauled Refuges expenence Prey capture rate pred l Vi Prey denSity Lesson Three Biological Control Biological Control use of one biological agent to control another biological agent 0 Pesticides I Problems Organisms evolve quickly quotpesticide treadmill Bioaccumulation DDT o Organisms that eat the pest accumulates pesticides and it travels down the food chain Fossil fuel derived Affects nontarget species 0 Negative effects of affecting the nontarget species is usually worse than the positive effects on the target species 0 Biological Pest Control I Introduced species to a new area that will consume the pest Ideally o Consistent low population of pests I No cycling of population 0 Reasonable but persistent predator population that can respond quickly Parasitism Lesson One Background parasitism is harmful to one party beneficial to another Parasites organisms that growfeedshelter on a host while negatively impacting the host 0 Live infeed on ont or only a few hosts over course of life I Kill or injure based on level of virulence and level of host defense 0 Life Cycle I Reproduction Uses host energy to replicate and can be transmitted to new hosts at this point Depends on rate at which new hosts are encountered I Infection Depends on probability of finding new host 0 Properties of a Parasitic Relationship I Transmission Parasite o Alter host behavior attract predator transport by host to environment feces attach to body Host 0 Detectavoid infected individualsenvironments smell I Infectivity Parasite 0 Trick immune systemdefenses Host 0 Recognition of nonself cell surface recognition I Reproduction Parasite 0 Efficient use of host resourcesmachinery levelefficiency will determine capacity to reproduce Host 0 Immune response 0 Parasite Growth Rate I Function of Reproduction how many resources can the parasite obtain from host InfectivityTransmission requires new living hosts Lesson One JIT HostParasite Interactions ReproductionTransmission o Parasites can only reproduce in a live host 0 Virulence increases as parasites use more host machinery to produce more progeny I Large virulence can decrease transmission Models of HostParasite Interaction o Arms Race I Parasite Transmissioninfectivity is very high virulence does not limit the parasite o Virulence will continue to increase I Host As virulence increases host increases defenses and continues to adapt o Prudent Parasite I Parasite Moderate transmissioninfectivity vs virulence balance I Host Moderate defense The costbenefit of defending should be an even proportion I It does not matter what point the system begins the end result will be intermediate relative to highest and lowest possible 0 Incipient Mutualism I Parasite Has positive value to host 0 Reduces negative effects in order to reduce host defenses I Host Reduce the defenses because parasites provide more benefits than cost Arms Race Prudent parasite Incipient mutualism parasite Parasite infectivitytransmission is Parasite is limited by The parasite has some very high therefore growth rate is transmissioninfectivity positive value to the not as limited by virulence Growth rate then host The parasite Virulence will continue to increase depends on a moderate adapts by reducing it s if possible level of virulence and negative effects as stabilizes at this point results in costly host defenses Host Defenses have costs but the Defenses have costs and Hosts reduce their parasite is so destructive that these costs are small compared to the benefits of having the best defense Defenses will continue to adapt to parasite and increase Ex cat bird and cow birds Mutualism the level defense is adjusted to be proportional to the virulence of the parasite Defenses stabilize at a moderate value 0 Cat bird ends up taking care of cow bird I Batfly parasite infects both species Cowbirds can pick and consume the flies and remove them from cat birds defenses because parasites provide more benefits than costs 0 Now the interaction is positive for both species mutualism Beneficial to both species extends beyond focal groups Obligate 0 Always the way two species interact I Affect the survivaldistribution of species 0 Ex antfungal mutualist community I Cultivar is the ants food supply I Parasite consumes the cultivar competes with ants The speciation of antscultivar is parallel as one diverges the other diverges to maintain mutualism 0 Evidence of close ties obligate relationship Facultative 0 May be mutualistic in some set of conditionsenvironments 0 Most dominant interaction on earth I Mycorrhizal fungus gets home plant gets fixed nitrogen Affects productivity and dispersal of plant Life History Lesson One Demographic Traits Organisms allocate energy to activities each occurring at a specific time sequence and duration 0 Life history is the pattern of these allocations Decisions 0 How long and fast to grow 0 Whenhow often to reproduce o Allocate energy to progeny I Growthmaintenance vs Reproduction JIT Lesson One If doing one thing would benefit more population growth why does that not happen 0 Because the repoductive benefit does not outweigh the energy costs I Energy is finite and limiting therefore there are tradeoffs Organisms seek to maximize the most beneficial energy investment Reproduction vs Survivorship Growth vs Reproduction Lesson Two Tradeoffs in GrowthBody Size RRV residual reproductive value expresses consequences of demographic traits for value of future generation Tradeoffs evaluated along a growthbody size dimension The concept of residual reproductive value RRV expresses the consequences of demographic traits for the value of future expected reproduction 0 III N RRVatagex 2 I N rxl 1 AgeSize is synonymous when size goes up we assume this means age 0 Sum the parameter from the age x1 until the age dies I As long as RRV increases the organism should be concerned about the future I When RRV peaks put all energy into current reproductive effort and do not worry about future o LtLX I If survivorship is less at a future age than at the current age x the number decreases I If the survivorship is good RRV is decreased I Fecundity will increase RRV directly 0 NXNt I If population is growing Nx gt Nt is small The contribution will be diluted in comparison progeny worth less in the future 0 Predict I When to produce I How often big bang one reproductive event semelparity Repeated iteroparity Examples of RRV vs size Size Beneficial A88 Size Detrimental Size Red Curve size detrimental 0 Should not sacrifice the reproduction of now bc RRV will decrease I Mate once semelparity 0 Density dependent factors not influencing species I Density independent abiotic competition is important 0 Best Strategy Breed at first opportunity Blue Curve size beneficial 0 Best Strategy 0 Characterized by density dependent competition I Size increases survival I and fecundity m I Moderate energy expenditure to allow for future survival Few progeny and parental care I Grow in early life reproduce at increasing slope and reproduce often lteroparous reproduction Practice Exam some questions may have multiple answers 1 Which of following factors can limit species distributions a Environmental conditions b The presence of other organisms c geographic feature such as a mountain range d Behavior e Historical event 2 You decide to examine a why a species is not found in an area Which factor do you test first a Limitation via dispersal b Limitation because of other organisms c Limitation because of the physical environment d Something else 3 Which of the following affect both large scale and small scale patterns of distribution of a species a Behavior b Interactions with other organisms c Dispersal d The physical environment 4 The order of priority first to last for how the following effects influence small scale distributions is the following a interactions with other organisms biotic factors b random dispersal c suitability of the physical environment abiotic factors 5 Which of the following indicates a population is growing a R is 1 b Lambda is 1 c Lambda is greater than 1 6 Which of the following if any is true about Ro a It measures the average number of progeny born to individuals that survive to aduhhood b It measures the time between the birth of parents and their offspring c It measures the average number of progeny born to an individual initially in the cohort d It equals A for a population with discrete non overlapping generations when the census time equals the organisms39 life span 7 Which of these are required for interspecies competition to occur a The two species be closely related b The two species both consume the same resource c A shared resource is limiting d One species interferes with the other s ability to gain a resource 8 Which of these will increase competition between species The two species are closely related The requirements of the two species are more similar A low abundance of a limiting resource One species is more efficient at gathering a resource High densities of either competitor f The two species are closely related 9 Which of the following statements about parasite reproduction is true a greater reproduction always leads to a greater growth rate b it is not detrimental to the host c it occurs outside the host DDPUP d it can evoke host defenses 10 Parasite population growth rate depends on a he ability to find a new host b the ability to reproduce inside the host c the ability to use multiple different host species d the ability to be a good competitor 5 6 7 8 9 1 A B C D and E a All of these factors may limit species The lesson explicitly mentions Environment interactions with other organisms and behavior While we did not explicitly list a geographic barier review the section on gypsy moths if you did not get this Ifyou did not include history think about how such events may influence some of the other factors A a In this case the right order to test things corresponds to which factors eliminate the possibility that the others are responsible If an organism cannot get to a given area than the other factors are irrelevant In contrast if we first showed that a species could not live in an area would we then know that this factor is responsible Make sure to understand what sequence of tests would give you the best chance of finding the right answer with the least effort A B C D random dispersal lt suitability of the physical environment abiotic factors lt interactions with other organisms biotic factors A and C C and D B and C B C and E D O A and B quotthe above questions obtained from Dr Mark Weissenburg s Learning Catalytics Assessments the above notes were obtained from his online lectures on BIOL 2344
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