Multiple Choice Review – Ecology 1. Which level of biological organization includes all others? a. Population b. Organism c. Community d. Ecosystem Questions #2-5 refer to the following information: Nitrogen is the most limiting mineral for plant growth. Although the atmosphere is 79% nitrogen, plants are unable to incorporate N2 into their tissues. Legumes have formed relationships with nitrogen-fixing bacteria, called Rhizobia, who convert N2 to NH3, a form of nitrogen that plants can use. These bacteria require a host plant for survival and often live in the roots of these plants where they receive nutrition from the plant while the plant receives a usable source of nitrogen from the bacteria. The equation for this process is shown below. N2 + 8H+ + 16 ATP  2 NH3 + H2 + 16 ADP + 16 P 2. What process is described by the equation above? a. Denitrification b. The nitrogen cycle c. Nitrogen fixation d. Nitrogen overload 3. How would the relationship between Rhizobia and a plant be classified? a. Parasitism b. Obligate symbiosis c. Commensalism d. Facultative symbiosis 4. Nitrogen fixation is only possible under anaerobic conditions. Which of the following is not something that would help to create this environment? a. Thick root walls that limit gas exchange. b. The presence of the plant protein leghemoglobin that binds to free oxygen. c. Specialized root stomata that allow the direct passage of oxygen from the soil into the roots. d. Lignin-rich cells that surround the bacteria, creating a boundary from the soil. 5. Which of the following is not an abiotic factor that affects the plant? a. Precipitation b. Temperature c. N2 availability d. Rhizobia availability

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Questions #6-8 refer to the following food web:

Source: http://pubs.usgs.gov/circ/circ1316/html/circ1316chap14.html

6. Phytoplankton require sunlight and nutrients, such as nitrogen and phosphorous, to produce food via photosynthesis. If a nearby farm uses an abundance of fertilizers, excess nitrogen and phosphorous will flow into the Chesapeake Bay. Which of the following local populations will not experience an immediate increase in density after such an event? a. Benthic invertebrates b. Bivalves c. Small planktivorous fish d. Gulls 7. Bivalves are filter feeders, meaning that they filter nutrients and food out of the water surrounding them. As pollutants enter the Chesapeake Bay, the bivalves take in these pollutants. Many bivalves are dangerous to eat from the Chesapeake Bay because they contain high levels of pollutants. Which of the animals below are not affected by the contaminated bivalves? a. Herbivorous ducks b. Osprey c. Sea ducks d. Bald eagle 8. Biomagnification is the process by which the level of contaminants increase as they move upwards in a food chain. If bivalves in the Chesapeake Bay become contaminated from run-off, which organism will experience the highest level of contamination? a. Bald eagle b. Tundra swan c. Bivalves d. Sea duck

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9. Pacific salmon are a type of salmon that are found in the Pacific Ocean. Although born in freshwater streams, these salmon spend the majority of their lives in saltwater. Depending on the species, Pacific salmon spend between one and eight years in the ocean before returning to freshwater to spawn. While in the ocean, they feed on a variety of organisms including kelp, copepods and crustaceans. Which of the following is a biotic factor affecting Pacific salmon? a. Water salinity b. Oxygen levels c. Copepod abundance d. Water temperature Questions #10-11 refer to the following information: The black rhinoceros is a mammal found in Africa. Weighing in at up to 1,350 kg, these rhinos can live roughly 35 years. Gestation in the black rhino lasts for 15-16 months, with calves staying under the mother’s parental care for up to four years. Black rhinos have been hunted extensively by humans for their horns. Poaching pressure has reduced the black rhino population to an endangered level. Ongoing efforts are attempting to save the animal from extinction. 10. How can the black rhino survivorship strategy be categorized? a. K-selection, type I b. K-selection, type III c. r-selection, type I d. r-selection, type III 11. What is the relationship between survivorship strategy and population recovery? a. K-selection populations recover quickly due to their short lifespan. b. r-selection populations recover slowly due to their early maturation. c. K-selection populations recover slowly due to their low fecundity. d. r-selection population recover quickly due to their extensive parental care. 12. Which of the following is not a result from predator-prey interactions? a. Cleaner wrasse, a coral reef fish, eat parasites off of larger fish. b. Planthopper, an insect, has the same shape and coloring of green leaves. c. Lynx have large, padded paws that enable them to walk quietly on snow. d. Scorpion venom is fast-acting and can paralyze or even kill other animals. 13. Where does intraspecific competition occur? a. Between members of two or more different species b. Between members of the same food web c. Between members of the same species d. Between any members of the same community

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Use the choices below to categorize the interactions described in questions #14-17. I. II. III. IV. V.

Commensalism Mutualism Competition Symbiosis Parasitism

14. Mistletoe is a plant that attaches to trees or shrubs. Special mistletoe structures called haustorium penetrate the branches of the trees and shrubs. The mistletoe is then able to absorb water and nutrients from the plant, leading to illness and sometimes death of the host plant. a. I b. II c. III d. V 15. Cecropia trees have hollow trunks that are inhabited by Azteca ants. The trees provide shelter and nutrients to the ants while the ants protect the trees from encroaching vines and herbivorous insects. a. I b. II c. IV d. II and IV 16. Orchids are epiphytes that grow on the bark of other plants. They do not harm the plant but obtain their nutrients and water from the surrounding air and debris. a. I b. II c. III d. V 17. The pelagic zone of the ocean is the area of the ocean that is neither close to the bottom nor close to land. There are a wide variety of organisms that inhabit the pelagic zone. Phytoplankton float along the surface, using photosynthesis to produce food. Zooplankton are tiny organisms that float in the surface waters and feed on the abundant phytoplankton. Krill, small crustaceans, also feed on phytoplankton. They display vertical migration in which they swim at deeper depths during the day and then come up to the surface waters at night to eat. What is the relationship between zooplankton and krill? a. I b. II c. III d. IV 18. Which of the following only includes individuals of a single species? a. Population b. Biome c. Ecosystem d. Community www.njctl.org

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Questions #19-21 refer to the trophic cascade illustrated by the following graphs:

Source: http://www.southernfriedscience.com/?p=12692

19. According to the information above, what is the relationship between sea urchins and kelp? a. Mutualism b. Predation c. Neutralism d. Obligate symbiosis 20. In 1997, the sea otter population plummeted. What effect did this have on the kelp? a. Kelp density increased due to decreased sea urchin biomass. b. Kelp density increased due to increased sea urchin grazing intensity. c. Kelp density decreased due to increased sea urchin grazing intensity. d. Kelp density decreased due to decreased sea urchin biomass. 21. The removal of sea otters led to the crash of the entire community. How would you classify the sea otter? a. Keystone species b. Autotroph c. Detrivore d. Abiotic

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Questions #22-23 refer to the following information: Many fisheries have exhausted the supply of large predatory fish in the oceans. As a result, the fisheries have moved down to the next trophic level on the food chain. This practice is called fishing down the food chain and has important implications for fisheries management. The following partial food chain applies to the North Sea. Juvenile Cod

Pout

Krill

Copepods 22. For decades, cod was the major fishery in the North Sea. When fishermen exhausted the supply of cod, they moved their focus to pout. With the removal of pout, the krill population increased which forced the copepod population to decrease. How would this affect the recovering cod stocks? a. Removing the predation pressure of pout would allow cod to recover faster. b. Decreasing the copepod population would make cod stocks recover slower. c. The increased competition of krill would make cod stocks recover faster. d. This would have no effect on recovering cod stocks. 23. For cod populations, what type of effect does fishing pressure exert? a. Dominant b. Density independent c. Competitive d. Density dependent 24. As the last ice age ended, glaciers retreated northward and trees colonized the new environment. During this time, the Scotch pine colonized the Norfolk region of Great Britain. The Scotch pine population grew exponentially for 500 years. As this initial growth rate slowed, what increased? a. Predation b. Carrying capacity c. Logistic growth d. Intraspecific competition 25. The mackerel, a marine fish, produces many eggs at a time. Out of 1 million eggs produced, only 10 will survive the first 70 days of life. What type of survivorship pattern do mackerel follow? a. Type I b. Type II c. Type III d. Not enough information

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26. When does competitive exclusion occur? a. When predators displace prey from their habitat. b. When different species compete for the same resources. c. When the same species competes for different resources. d. When prey displace predators due to a competitive advantage. 27. When would it be appropriate to conduct an exclusion experiment? a. When obtaining a population count for a species. b. When studying how one species affects another species in the same community. c. When studying survivorship strategies of two or more different species. d. When studying how a species from one community would affect another species from a different community. 28. Food webs and food chains both show interactions between trophic levels. What is the difference between the two? a. A food web shows several food chains in a community. b. A food chain shows four trophic levels while a food web shows unlimited trophic levels. c. A food chain shows several food webs in a community. d. A food chain has a trophic energy transfer of 20%. 29. In aquatic ecosystems, phytoplankton diversity is extensive despite the limited resources available. First observed in 1961 by G.E. Hutchinson, this has been coined “the paradox of the plankton.” What usually occurs under conditions of limited resources? a. Competitive exclusion leads to the dominance of one species. b. Mutualism leads to a variety of species via symbiosis. c. Keystone species are eliminated, leading to the crash of the ecosystem. d. Facultative symbionts become obligate symbionts. 30. Which of the following is not an example of interspecific competition? a. A shrub and a vine competing for sunlight in the understory of a dense forest. b. Cheetahs and lions competing for gazelle and zebra. c. Two male moose competing for a female during mating season. d. Different bird species compete for nest sites in trees. 31. In a study of two flour beetle species, Tribolium castaneum and Tribolium confusum, it was found the beetles prey on the eggs of both their own species and other species. When studied in the same environment, T. castaneum was found to be a stronger competitor for resources and was able to exclude T. confusum 84% of the time. Adelina is an intracellular parasite that can infect both species of beetle. When Adelina was present in a community and had infected both species of beetle, the competitive interactions were reversed. In an infected community, T. confusum was able to outcompete T. castaneum. This example illustrates that when a variety of interactions happen in the same community, surprising results sometimes occur. What interaction is not present in the situation described above? a. Predation b. Commensalism c. Competition d. Parasitism

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Questions #32-34 refer to the following information: Every two to seven years, the eastern Pacific Ocean experiences the El Nino Southern Oscillation (ENSO), which brings warm surface waters and high air pressure. Under normal conditions, winds blow warm surface water away from the coast and are replaced with cold, nutrient-rich water from the ocean bottom. These nutrients support immense primary production by the phytoplankton which form the base of the food chain. During an ENSO event, surface winds weaken. Warm water is not moved away from the coast and nutrients from bottom waters are not brought to the surface. ENSO events bring extreme weather across the globe and have effects on both farming and fisheries. A basic food chain from the eastern Pacific Ocean is shown below. Predators (Whales, birds, sea lions)

Forage Fish (Herring, sardine, anchovy, Pollack)

Zooplankton

Phytoplankton 32. Based on the description of ENSO above, which of the following is not a plausible result from an ENSO event? a. Fish migrations, as fish travel to other areas in search of food. b. Massive fish kills, in which fish that have starved wash onto the shore. c. Exponential growth in the sea lion population. d. The collapse of the anchovy fishery. 33. For the phytoplankton populations, ENSO would be considered what type of factor? a. Biotic b. Abiotic c. Symbiotic d. Competitive 34. In this food chain, how would phytoplankton be classified? a. Keystone species b. Obligate species c. Primary consumers d. Dominant species www.njctl.org

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Questions #35-36 refer to the following information: In 1976, the dominant finch on Daphne Major in the Galapagos Islands was the medium ground finch, with a population of 1,200. In 1977, a drought struck the island negatively affecting most of the vegetation. As a result, the population of medium ground finch dropped to 180 due to starvation. In 1983, however, a large amount of rainfall fell on the island creating optimal conditions for vegetation. The medium ground finch population increased to 1,100. 35. What type of factor affected medium ground finch populations in 1977 and 1983? a. Density independent b. Logistic c. Density dependent d. Biotic 36. After the rainfall of 1983, what type of population growth did the medium ground finch experience? a. Logistic b. Quantitative c. Exponential d. Abiotic 37. The ecologist Adolph Murie studied survival of Dall sheep in Mount Danali National Park. Some of the information he gathered is presented in the table below. Based on this information, what type of survivorship pattern do Dall sheep follow? Age (years) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 10-11 11-12 12-13 13-14 14-15 a. b. c. d. www.njctl.org

Number of survivors at the beginning of each year 1,000 801 789 776 764 734 688 640 571 439 252 96 6 3 0

Type I Type II Type III Type IV AP Biology

Ecology

Questions #38-40 refer to the following information: A well-known ecological field study involved rodents in the Chihuahuan Desert, Arizona. The study consisted of 9 different species, divided into three categories: large granivores (animals that eat seeds), small granivores, and small insectivorous rodents. Ecologists wanted to determine the effect of large granivores on the abundance of smaller rodents. Experimental Design: Researchers built eight 50m by 50m plots that were surrounded with small wire mesh fencing. On four of the plots, holes were cut in each side of the fence that were large enough to allow free passage of all rodents. On the other four plots, smaller holes were used that would only allow passage of small rodents. These plots were referred to as semi-permeable. 38. Researchers hypothesized that large rodents compete with small rodents. If this hypothesis were correct, what would be a likely result of the exclusion experiment? a. Small rodent populations would decrease in the semi-permeable plots. b. No population change would be observed in the semi-permeable plots. c. Small rodent populations would increase in the semi-permeable plots. d. Large rodent populations would increase in the semi-permeable plots. 39. In the first three years of the experiment, small granivore populations increased 3.5 times in the semi-permeable plots. In these same plots, however, small insectivorous populations did not change. How can these results be explained? a. Large granivores only compete with small insectivorous populations. b. Competition is not a factor in the community ecology of desert rodents. c. Small granivores are a keystone species of the desert ecosystem. d. Competition that occurs between large and small rodents is a result of nutrient availability. 40. Four out of the eight study plots were made semi-permeable. What was the purpose of maintaining the four plots that were not semi-permeable? a. These plots contained control populations to which the populations in the semipermeable plots could be compared. b. These plots were held in reserve, to be used if something negative happened in the semi-permeable plots. c. These plots allowed the ecologists to study the feeding habits of the large granivores. d. These plots were maintained in order to be used in an identical study that would increase the initial study’s reliability.

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Quantitative Review – Ecology

Questions #1-2 refer to the following graph of logistic population growth:

1. At what value on the y-axis does the population reach its carrying capacity? 2. At the carrying capacity, the growth rate of the population approaches what value? 3. In a basic food chain for a meadow community, flowers are consumed by herbivorous insects. Herbivorous insects are consumed by rodents who are, in turn, consumed by a variety of predators. If the biomass of flowers is 10,000 kg, what is the approximate biomass of the secondary consumers? 4. Each trophic level in a food chain is only able to assimilate a certain amount of the energy available to them into growth. If 1,000,000 J of sunlight in a valley results in 10,000 J of energy stored in primary producers, what is the production efficiency of the primary producers? 5. Production efficiency varies by organism. Birds have a production efficiency of about 1% while fish are more efficient at 10%. Insects have even higher production efficiencies at 40%. If 200 J of energy are available to a grasshopper, how much of that energy will the grasshopper not be able to assimilate into new growth? 6. The basic equation for exponential growth is N = N0 ert Where N0 is the starting population, r is the rate of growth, and t is time. A population of buffalo in Kruger National Park numbered 29,359 in 1991. After this census was complete, a severe drought affected the region. By 1995, the population had dropped to 14,123. The following two years brought ample rainfall that allowed the buffalo population to begin recovery. If the growth rate of the population between 1995 and 2006 was 0.078, what was the population in 2006? Write your answer with two significant digits.

ANSWER KEY www.njctl.org

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Ecology

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24.

D C B C D D B A C A C A C D D A C A B C A B D D

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25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40.

C B B A A C B C B D A C A C D A

1. 2. 3. 4. 5. 6.

1 0 100 kg 1% 120 J 3.3 x 104 buffalo

Ecology