ECOLOGY FINAL REVIEW - EXAM 2 HOMEWORK

1. A researcher is investigating differences in behavior of young mice of different ages. This would be an example of which of Tinbergen's four questions?
a. Adaptive Significance
b. Mechanism
c. Ontogeny
d. Phylogeny
Click the card to flip 👆
1 / 71
Terms in this set (71)
1. A researcher is investigating differences in behavior of young mice of different ages. This would be an example of which of Tinbergen's four questions?
a. Adaptive Significance
b. Mechanism
c. Ontogeny
d. Phylogeny
C

(The investigator is looking at a developmental series.)
A researcher studying a beetle finds that those in higher elevation develop at faster rates than those at lower elevation. To investigate whether this difference is genetic and the fitness consequences of the developmental differences, the researcher transplants beetles from higher to lower elevations (and vice versa). The primary research objective here falls into which one of Tinbergen's four questions?
a. Adaptive Significance
b. Mechanism
c. Ontogeny
d. Phylogeny
A

(Fitness consequences should cue you in to the question being one of adaptive significance.)
Which of the following is not an extended phenotype?
a. Burrows of mice
b. A beaver dam
c. The fan of a peacock's tail
d. A bower bird's nest
e. All of the above are extended phenotypes.
C
(A peacock's tail is a regular phenotype, not an extended one.)
Optimal foraging theory generally has been most successful in predicting the behavior of
a. Birds
b. Mammals
c. Animals whose prey is sessile.
d. Animals whose prey is motile.
C
Recall the mouse burrowing study discussed in class. Which statement about it is false?
a. The escape tunnel and the size of the burrow were influenced by different genes.
b. The oldfield mice had more complex burrows than those of other mice.
c. The allele or alleles involved in constructing escape tunnels is/ are dominant.
d. All of the above are true; none is false.
d
The numbers of a shrub were counted at four quadrants of 20 meters by 20 meters. In these 52, 39, 31, and 18 shrubs were found. What is the density of shrubs per ha (100 meters by 100 meters)?
a. 35
b. 175
c. 500 d. 875
D

(The average number of shrubs is 35.

But there are 25 (5 x 5) quadrants per Ha.

35 x 25 = 875.)
250 moths are captured at a site. They are marked and released. Two days later, 400 moths are captured. Of these 20 are marked. Assuming that the assumptions of estimating by mark-release-recapture are met, what is the estimate of the population size?
a. 670
b. 1000
c. 1340
d. 5000
e. 100,000
D

(Remember that the proportion of marked individuals ought to be the same from day to day.
250 moths were captured and marked the first time. But we don't know how many were there - call that X.

We know that the second time, 400 were caught, of which 20 were marked

X/ 250 = 20/400.

Solve for X.

X is 5000.)
What statement about estimating population size by mark-release-recapture is false?
a. It assumes that marking does not affect the ability of recapturing the individuals that are marked.
b. It assumes no movement into or out of the population.
c. It only provides estimates of relative population size, not absolute numbers.
d. In implementing the study, one should know something about the natural history of the species.
All of the above are true; none is false
C
True or false: A population can consist of individuals of two different species
False
True or False: A metapopulation is a group of populations that are loosely connected by dispersal
True
True or false: A source population is a population within a metapopulation that cannot be sustained without migrants from other populations.FalseA population of beetles follows the logistic growth curve. If its growth rate at very low density is 9 percent per year, what would you expect its growth rate to be when the population is at 2/3rds of its carrying capacity? a. 0 percent b. 3 percent c. 4.5 percent d. 6 percent 9 percentB (The realized r = intrinsic r times (K-N)/K. The intrinsic growth rate here is 9 percent. When N is 2/3 K, the realized growth rate should be a third of the intrinsic growth rate)A population is growing exponentially at 5 percent a year. About how long will it take for it to increase by four fold? a. 14 years b. 20 years c. 28 years d. 40 years e. 56 yearsC (The doubling time is ln 2 / r = 0.7/ r or 14 years. Two doubling times are needed for the population to grow four fold)A population of snails is growing according to the logistic equation with an intrinsic growth rate of 12 percent a year. If its population size is 4000 in one year and the carrying capacity is 8000, what would you expect its population size to be in the following year? a. 4060 b. 4120 c. 4240 d. 4480C (The population is at half the carrying capacity so the realized r should be ½ the intrinsic r or 6 percent. 6 percent of 4000 is 240)During a hurricane, a large segment of an insect population is carried to a distant island where there are abundant resources and minimal predators. What type of growth would you likely expect in the time immediately following this colonization event? a. Logistic b. Linear c. Declining d. ExponentialDWhich equation best describes the pattern of population dynamics of the sheep in Tasmania from their introduction to the present day? a. dN/dt = rN b. dN/dt = rN(1 ‒ N/K) c. dN/dt = rK(1 ‒ K/N) d. dN/dt = rK(1 ‒ N/K)B (logistic equation)Which statement about Nicholson's experiments with blowflies is true? a. Population cycles occurred when adults had limited food and maggots had unlimited food. b. Population cycles occurred when both maggots and adults had unlimited food. c. Population cycles occurred when both maggots and adults had limited food. d.Population cycles occurred when adults had unlimited food andmaggots hadlimited foodDA population of turtles contained 342 individuals at the end of the year 2013. Since then, 44 have died, 37 were born, 17 immigrated, and 6 emigrated. What is the population size now? a. 298 b. 335 c. 346 d. 385CThe logistic equation assumes that a. the per capita growth rate is a constant. b. the per capita growth rate declines with increasing density. c. populations will increase in size indefinitely. d. r increases in a straight line as density increases.BThe study about Gambian children born during the hungry years shows a. The effects of poor nutrition around birth manifests during early childhood but are gone by age 3 or 4. B. The effects of poor nutrition around birth can last for decades. c. The effects of poor nutrition around birth cause the population to go into logistic growth.BTrue or false. With a semi log plot, the population of exponentially growing population follows a straight line when plotted against time.TrueTrue or false. A open population will be constant in number if B = DFalseTrue or false. The outbreak of hantavirus in the southwest US during the 1990s occurred because the predators of the disease-carrying mice disappeared.FalseTrue or false. Delayed density dependence is the likely cause for many population cycles.TrueThere are 34 predators and 348 prey in a predator prey system that follows the rules of Lotka Volterra dynamics. Assume that the growth rate of the predator population is 0.3, the capture efficiency is 0.02, and the assimilation coefficient is 0.03. What should we expect to happen to the prey population in the next time period? a. It should increase. b. It should decrease. c. It should stay the same.B (The isocline for prey is P= r/a. When the predator population is above this line, the prey population should decline. This figure is 15, which is much lower than the predator population size)There are 34 predators and 348 prey in a predator prey system that follows the rules of Lotka Volterra dynamics. Assume that the growth rate of the predator population is 0.3, the capture efficiency is 0.02, and the assimilation coefficient is 0.03. What should we expect to happen to the predator population in the next time period? a. It should increase. b. It should decrease. c. It should stay the same. d. not enough infoD (need mortality rate)In the Lotka Volterra equations for predator- prey dynamics, what does b stand for? a. The capture efficiency b. The assimilation efficiency c. The intrinsic growth rate of the predator population. The intrinsic growth rate of the prey populationBAssume we are dealing with a Lotka Volterra predator prey system. Also assume that the capture efficiency of the predator increases over time, what should we expect to happen to the long term average population size of the predator and the prey populations? The predator population should _________ in size and the prey population should _________ in size. a. Increase; increase b. Increase; decrease c. Decrease; increase d. Decrease; stay the same e. Decrease; decreaseE (If the capture efficiency (a) increases, the prey population should decrease - its isocline is N = r/a. More efficient predators mean more prey are being consumed. The predator population should also decrease - its isocline is m/ ba. More efficient predation actually - ironically - should reduce the long term average of the predator population.)Females in the wasp genus Nasonia typically lay eggs in the pupa of blowflies. The wasp eggs hatch into larvae, and the larvae kill and eat the fly pupa. Based on these observations, which statement is false? a. The wasps and the blowflies are engaged in a predatory relationship. b. The wasps are parasitoids. c. The wasps can be thought of as both predators and parasites, albeit unusual ones. d. The wasps are generalist.DMany species of butterflies are noxious to predators. They also have bright red coloration that indicates to the potential predators that they are unpleasant or even harmful to eat. This is an example of _______ coloration. a. exploitative b. cryptic c. apomitic d. aposematicDMoths resting on the trunks of trees often resemble the tree bark so that potential predators do not perceive them as prey. This is an example of a. crypsis. b. an induced defense. c. aposematic coloration. d. exploitationADifferent species of marine snails that are preyed on by a shore crab differ in terms of how easily the crab can crush their shells. Studies of these snails have provided evidence for the a. value of "gene silencing" in ecological studies. b. principle of compensation. c. presence of trade-offs between different antipredator adaptations. d. influenceof exploitation inthe distribution and abundance of food organismsCHuge numbers of adult periodic cicadas emerge simultaneously from pupae at intervals of either 13 or 17 years. This phenomenon is most similar to which of the following? a. Masting b. Compensation c. Induced defense d. AposematismA (In both cases, the species are putting out large numbers of offspring all at once such that the predators cannot eat them all)Insects feeding on the leaves of a plant stimulate the plant to produce more leaves. This is an example of a. aposematism. b. compensation. c. competition. d. an induced defenseBSuppose that rabbits are the only prey and food supply of foxes, and that the predator‒prey interaction follows Lotka‒Volterra dynamics. The mortality rate of foxes in the absence of rabbits is 0.1 per week, and the intrinsic growth rate of rabbits in the absence of predation is 0.2 per week. The capture efficiency is 0.002, and the efficiency at which rabbit biomass is converted into fox biomass is 0.2. If there are 30 foxes in a population, and 400 rabbits are present, the rate at which prey will be killed is _______ per week a. 24 b. 30 c. 80 d. 120 e. 240eThe Lotka‒Volterra predator‒prey model of population growth a. does not depend on the availability of the predator's resources. b. is independent on the prey's resources. c. does not change when the predator population declines. d.assumes that when predators are absent the prey population grows exponentiallyDIn Huffaker's studies of an herbivorous mite and its mite predator, when predator and prey were in a simple environment, a. prey and predator populations both increased for a while, but soon crashed and went extinct. b. prey soon went extinct, but predators persisted. c. predators soon went extinct, but prey persisted. d.predators and prey persisted and exhibited population cyclesAA bacterium that lives in human intestines is harmless in most people but can be deadly in immunocompromised people. We can say that the bacterium normally is in a(n)________ relationship but is in a(n) _________ relationship with immunocompromised people. a. Exploitative; commensal b. Commensal: amensal c. Commensal; exploitative d. Amensal; commensal e. Amensal; exploitativeCIn which type of ecological relationship is one partner harmed but the other is unaffected? a. Mutualism b. Commensalism c. Amensalism d. ExploitativeCThe presence of the flour beetle Tribolium castaneum reduces the number of its related species, T. confusum. Is this evidence that the species are in a competitive relationship? a. Yes! b. Maybe. We first have to see whether T. confusum also reduces the number of T. castaneum. c. Maybe. We first have to see whether the two species eat the same food. d. No. It shows that T. castaneum is a predator of T. confusum.BThe first vaccine was developed against which disease. a. Measles b. Smallpox c. Influenza d. COVID-19BA bacterium that lives inside an aphid is always classified as a(n) a. parasite. b. parasitoid. c. symbiont. d. ectoparasiteCWhich statement is true? a. All pathogens are parasites. b. All parasites are pathogens. c. All symbionts are parasites. d. All symbionts are mutualists.AA bacterium that causes rash on the skin of mammals upon infection would be classified as a(n) a. ectoparasite. b. endoparasite. c. parasitoid. d. macroparasite.AWhich is an advantage that endoparasites have over ectoparasites? a. Dispersal ability b. Ease of feeding c. Less susceptibility to the host's immune system d. A simpler life cycleBHow does the protein transferrin assist in defenses against parasites? a. It is used in encapsulating parasite eggs. b. It removes iron from the blood serum in vertebrate hosts and stores it in intracellular compartments. c. It paralyzes nematode parasites. d. . It allows "memory cells" of the immune system to store information about pathogens, thus providing lifelong immunity.BAccording to the basic host-pathogen model, if the combined death and recovery rate from a disease doubles, and the effectiveness of the disease to spread from infected to uninfected individuals remains the same, the threshold density should a. decrease by a factor of four. b. decrease by half. c. stay the same. d. double.DIn the simple host-pathogen model, which term describes the rate at which a susceptible individual encounters an infected individual? a. SI b. S c. dI d. mIAThomas Park's studies of flour beetles and their protozoan parasite best exemplified the principle that a. parasites can alter the outcomes of competitive interactions between species. b. there are costs to both host defenses and parasite counterdefenses. c. selection can favor a diversity of host and parasite genotypes. . d. parasites can drive host populations to extinction.ASuppose a human pathogen has an R0 of 5. Assuming that infection or vaccination provides perfect immunity, what proportion of the population need to be vaccinated or previously infected to reach herd immunity? a. 20 percent b. 50 percent c. 70 percent d. 80 percentD (1- (1/R0))What is the most likely reservoir host of SARS-CoV-2? a. Civets b. Pangolins c. Bats d. Camels e. MiceCA virus present in birds starts infecting a few handlers of the birds. What is this an example of? a. Hemiparasitism b. Zoonosis c. Herd immunity d. Inoculation e. PhytoalexinBIn the equation for determining the critical threshold size for a disease outbreak, what does the term mI represent? a. The number (or density) of individuals that are newly infected. b. The number (or density) of individuals that are no longer infectious thanks to death or recovery. c. The rate at which individuals are infected. d. The rate at which predators eat prey. e. The number (or density) of prey eaten by predatorsBConsider the mushroom feeding Drosophila / nematode system. Which statement is false? a. Some mushroom feeding flies are better at withstanding nematode parasitism than others. b. Adult flies usually court and mate on mushrooms. c. The nematodes infect flies at the adult stage. d. Flies that emerge from mushrooms that have large quantities of alpha amanitin are less likely to be parasitized than flies that come from mushrooms with little alpha amanitinCTrue or false - Phytoalexins are part of the plant immune systemTrueTrue or false - A mammal that has two sets of identical alleles at MHC genes is usually better able to ward off pathogens than one with a diverse complement of MHC alleles.FalseWhich of the following was a finding of Tansley's experiments with bedstraw plants? a. The species that was restricted to acidic soils excluded the species that was adapted to calcareous soils when grown on acidic soils. b. The species that grew on calcareous soils was physiologically incapable of growing on the acidic soils. c. The species that grew on acidic soils was physiologically incapable of growing on the calcareous soils. d. The two species did not compete with each other when grown together.AWhich of the following is not an example of a resource? a. A stenocara beetle captures water from fog that condenses on its back. b. An increase in temperature increases aggressiveness in a species of coral reef fish. c. Dung beetles collect and store dung to be used as a food source for their larva. d. A bumblebee collects nectar from a flowering plant.BTwo species of birds feed on berries. The birds are active at different times of the day and do not come into contact with one another. Nonetheless, the presence of one species limits the survival and reproduction of the other. What type of competition is this? a. Interference b. Exploitation c. Allelopathy d. Logistic e. Apparent f. This is not an example of competition.BTwo species of grasshoppers live in the same area. They both feed on plants, but the presence of one species does not affect the survival or the reproduction of the other. What type of competition is this? a. Interference b. Exploitative c. Allelopathy d. Apparent e. This is not an example of competitionEBlack walnut trees release chemicals that can be toxic to other plants. This phenomenon may be an example of _______, although experimental confirmation is still needed. a. competitive exclusion b. exploitative competition c. allelopathy d. character displacementCIn Brown and Davidson's study of seed-eating rodents and ants in Arizona, the number of rodents _______ when ants were removed, and the number of ant colonies _______ when rodents were removed. a. increased; increased b. increased; decreased . c. decreased; increased d. decreased; decreasedAIn his experiments with different competing pairs of Paramecium species, Gause found that sometimes both species persisted and sometimes only one species did. Which hypothesis did Gause propose in order to explain the cases in which both species persisted? a. One species was a much better competitor than the other. b. Periodic disturbance allowed for coexistence. c. The two species tended to use different resources. d. The two species exhibited only interference competition, not exploitative competitionCWhich statement was supported by Stomp and colleagues' study of the partitioning of resources between two species of Baltic Sea cyanobacteria? a. One feeds on large species of other bacteria, while the other feeds on smaller ones. b. One tends to stay close to the surface of the water, and the other tends to stay near the bottom. c. One uses short (green) wavelengths of light efficiently, while the other uses longer (red) wavelengths. d. One uses nitric oxide efficiently, while the other uses ammonium efficientlyCSuppose that, instead of the results actually obtained in Brown and Davidson's experiments, the number of rodents in the ant-excluded treatment was roughly the same as the number of rodents in the control group, and the number of ants in the rodent-excluded treatment was roughly the same as the number of ants in the control group. Which of the following would you then conclude? a. Competition is asymmetrical, with rodents affecting ants more than ants affect rodents. b. The two species have reduced competition through resource partitioning. c. Competition is asymmetrical, with rodents affecting ants less than ants affect rodents. d. The rodents and ants are engaged in apparent competition.BCharacter displacement is likely to _______ the competition coefficients in two competing species and to _______ resource partitioning. a. increase; increase b. lower; increase c. lower; decrease d. increase; lowerBA population of Drosophila melanogaster with 10,000 individuals and a carrying capacity of 40,000 follows the logistic growth equation. Suppose that 5,000 individuals of a competitor species, Drosophila simulans, are added to the population, and that this species has an α of 0.5. One would predict that this number of competitive individuals will decrease the D. melanogaster population growth rate by the same amount as the addition of _______ D. melanogaster individuals would. a. 1,000 b. 2,500 c. 5,000 d. 7,500 e. 10,000B (N2 x α is 5000 x 0.5 - which is 2500)A population at the zero population growth isocline is a. increasing in size via exponential growth. b. stable in size. c. decreasing in size. d. increasing in size via logistic growthBA population of white oak trees with 500 individuals and a carrying capacity of 1,500 follows logistic growth. Under ideal low-density conditions, its growth rate is 0.15 per year, but it faces competition from a population of 1,000 Chapman oaks with an α of 0.5. What is the expected growth of the population of white oaks in the next year? a. 0 b. 25 c. 50 d. 75BThe intrinsic growth rate is 0.15. It is reduced by N/ K or (500/1500) by intraspecific competition and by (αN2/K) or(1000 * 0.5/ 1500) by interspecific competition. This the realized r is 1/3 (0.15) or 0.05. We expect the population to increase by the realized r times N. That is 0.05 x 500 or 25. 14. By pitting two species of worms against each other at varying densities, researchers have determined that the zero growth isocline of species A is always above that of species B. This means that a. species A will always exclude species B. b. species B will always exclude species A. c. one species will exclude the other, depending on the initial conditions. d. both species will coexist at a lower density than either would alone.ABased isocline with all arrows in same direction, what is the expected outcome of the competition between species 1 and species 2? a. Coexistence b. Competitive exclusion of species 2 by species 1 c. Competitive exclusion of species 1 by species 2 d. Persistence of one species only; whichever one persists will depend on the initial conditions