Ch. 39 Community Ecology
Which of the following statements about an ecosystem receiving a moderate level of continued disturbance are true? Check all that apply. ____ A moderate level of continued disturbance predicts that most communities eventually reach an end-state or climax community. ____ A moderate level of continued disturbance should lead to increases in species richness. ____ A moderate level of continued disturbance tends to lead to the dominance of K-selected species. ____ An example of a moderate level of continued disturbance would be a tree fall in a mature rain forest. ____ A moderate level of continued disturbance should lead to all successional stages being present in the community at the same time.
A moderate level of continued disturbance should lead to increases in species richness. An example of a moderate level of continued disturbance would be a tree fall in a mature rain forest. A moderate level of continued disturbance should lead to all successional stages being present in the community at the same time.
Which of the following statements about the fundamental and realized niche are true? Check all that apply. ____ A species' realized niche could be the same size as its fundamental niche. ____ A species' realized niche could be smaller than its fundamental niche. ____ A species' fundamental niche can be smaller than its realized niche. ____ A species' realized niche could be the same size as its fundamental niche. ____ A species' realized niche could be smaller than its fundamental niche.
A species' realized niche could be the same size as its fundamental niche. A species' realized niche could be smaller than its fundamental niche. A species' realized niche could be the same size as its fundamental niche. A species' realized niche could be smaller than its fundamental niche.
The amount of sunlight that falls on plant leaves and is captured by photosynthesis is approximately _____ A. 1% B. 10% C. 25% D. 50%
A. 1%
Even though nitrogen constitutes 78% of Earth's atmosphere, the amount available for living things nearly all comes from A. a few groups of nitrogen-fixing bacteria. B. the breakdown of minerals. C. a few genera of detritivores. D. the breakdown of dead plants. E. nitrogen-containing fertilizers.
A. A FEW GROUPS OF NITROGEN-FIXING BACTERIA
What feature do the carbon and nitrogen cycles have in common? A. a large atmospheric component B. involvement in global climate change C. often a limiting nutrient D. mostly local cycling E. many microbes involved in cycling
A. A LARGE ATMOSPHERIC COMPONENT
The cyclic path that involves both biological and chemical processes of an ecosystem is called a _________ A. biogeochemical pathway. B. complete pathway. C. hydrological pathway. D. complementary pathway.
A. BIOGEOCHEMICAL PATHWAY
NPP is the difference between plant photosynthesis and respiration. Therefore, NPP quantifies the net absorption of what element by living plants? A. carbon B. phosphorus C. nitrogen D. oxygen E. sodium
A. CARBON
It is a situation in which a palatable organism resembles another kind of organism that is distasteful or toxic. A. coevolution B. defensive coloration C. camouflage D. secondary chemical compounds E. Batesian mimicry
A. COEVOLUTION
All organisms living together in a place are called a A. community. B. population. C. species. D. ecosystem.
A. COMMUNITY
Communities with a high level of bacterial diversity are found in many habitats including soil and aquatic environments. Recent studies indicate this diversity is crucial to the functioning of these communities. The same studies have also found that phage abundance plays a critical role in the maintenance of the bacterial diversity within these communities. Are phages a density-dependent or a density-independent regulating factor? A. density-dependent B. density-independent
A. DENSITY DEPENDENT
Vampire squid (Vampyroteuthis infernalis) are deep-sea cephalopods with features of both octopods and squids. Extensive deep-sea video recordings show the diet of the vampire squid consists of items like crustacean remains and fecal pellets. Which of the following terms describes the position of the vampire squid in the deep-sea trophic pyramid? A. detritivores B. omnivores C. herbivores D. carnivores
A. DETRITIVORES
Succession happens because species in the habitat alter that habitat in ways that assist other species. There are three dynamic concepts that are of critical importance for succession to take place. They are A. establishment, facilitation, and inhibition. B. symbiotic relationships, facilitation, and aposematic coloration. C. establishment, coevolution, and competitive exclusion. D. competition, climax communities, and tolerance. E. competition, inhibition, and coevolution.
A. ESTABLISHMENT, FACILITATION, AND INHIBITION
Which of the following is a producer? A. gymnosperm B. cricket C. garden spider D. blue jay E. red-tailed hawk
A. GYNOSPERM
Garlic mustard is an invasive plant species in North American temperate forests. Garlic mustard secretes an allelochemical that interferes with relationships between native tree roots and their mycorrhizal fungi. This would be an example of A. interference competition. B. exploitative competition.
A. INTERFERENCE COMPETITION
Competition between species is called ____________ A. interspecific. B. exploitative. C. interference. D. fundamental. E. intraspecific.
A. INTERSPECIFIC
Alligators excavate holes in the bottom of bodies of water. During times of severe drought these holes act as refugia for various aquatic organisms that might perish if there were no water available. Thus, alligators in this system can be classified as a(n) A. keystone species. B. symbiotic species. C. sympatric species. D. allopatric species. E. refugistic species.
A. KEYSTONE SPECIES
What structures evolved in the Acacia in order to develop a mutualistic relationship with the Pseudomyrmex ant? A. nectaries and Beltian bodies B. nectaries and tough fibrous leaves C. hollow thorns and a fibrous root system D. secondary compounds and Beltian bodies E. secondary compounds and tough fibrous leaves
A. NECTARIES AND BELTIAN BODIES
Which of the following biogeochemical cycles contain a mineral component? A. phosphorus B. carbon C. nitrogen D. oxygen E. water
A. PHOSPHORUS
In a marine ecosystem with an inverted biomass pyramid, which trophic level should have the smallest number of organisms? A. phytoplankton B. zooplankton C. primary carnivores (sardines) D. secondary carnivores (tuna) E. detritivores
A. PHYTOPLANKTON
The combustion of fossil fuels is altering the balance between photosynthesis and ___________ A. respiration. B. sunlight. C. growth. D. decomposition.
A. RESPIRATION
The rate of production of new biomass by heterotrophs is called A. secondary productivity. B. primary productivity. C. consumer productivity. D. gross productivity. E. net productivity.
A. SECONDARY PRODUCTIVITY
What type of relationship is it when two or more kinds of organisms live together in often elaborate and more or less permanent association? A. symbiotic B. parasitic C. mutualistic D. synergistic
A. SYMBIOTIC
Resource partitioning can often be seen in similar species that occupy the same geographic area. These species avoid competition by living in different portions of the habitat or by utilizing different food or other resources. They are referred to as being ____________ A. sympatric. B. allopatric. C. competitive. D. fundamental. E. exploitative.
A. SYMPATRIC
Cardiac glycosides, molecules causing a drastic effect on vertebrate heart function, are produced as defensive chemicals by plants belonging to A. the milkweed and dogbane families. B. the mustard family. C. the grass family. D. the poison ivy, oak, and sumac families. E. the bean family.
A. THE MILKWEED AND DOGBANE FAMILIES
A good average value for the amount of energy that reaches the next trophic level is about A. 20%. B. 10%. C. 5%. D. 2%. E. 1%.
B. 10 %
A species that plays a critical role in maintaining the structure of an ecological community and helps to determine the types and numbers of various other species in the community is known as A. a predator. B. a keystone species. C. the primary species. D. the dominant species. E. the alpha species.
B. A KEYSTONE SPECIES
A permeable underground layer of rock, sand, and gravel saturated with groundwater is called a(n) ________ A. natural spring. B. aquifer. C. hot spring. D. submergence.
B. AQUIFER
Which of the following is an example of commensalism? A. a tapeworm living in the intestines of a mule deer B. barnacles hitching a ride on the skin of a whale C. a female mosquito sucking blood from a musk oxen D. wood-digesting flagellates living in the gut of termites E. acacia trees and their ants
B. BARNACLES HITCHING A RIDE ON THE SKIN OF A WHALE
The net weight of all of the organisms living in an ecosystem is its A. productivity. B. biomass. C. vital force. D. photosynthesis minus metabolism. E. combined output of metabolism and photosynthesis.
B. BIOMASS
Cattle egrets follow African ungulates such as African buffalo around and catch insects that the buffalo flush. Oxpeckers perch on the backs of buffalo and feed on ectoparasites that infest the buffalo. Which one of the following shows the ecological interaction that the buffalo has with each bird? A. Cattle Egret: mutualism; oxpecker: commensalism B. Cattle Egret: commensalism; oxpecker: mutualism C. Cattle Egret: competition; oxpecker: mutualism D. Cattle Egret: mutualism; oxpecker: mutualism E. Cattle Egret: commensalism; oxpecker: commensalism
B. COMMENSALISM; MUTUALISM
Chemical compounds produced by plants that are not components of major metabolic pathways. A. coevolution B. defensive coloration C. camouflage D. secondary chemical compounds E. Batesian mimicry
B. DEFENSIVE COLORATION
In an ecosystem A. both energy and nutrients cycle. B. energy flows and nutrients cycle. C. energy cycles and nutrients flow. D. both energy and nutrients flow. E. energy is contained with nutrient cycles.
B. ENERGY FLOWS AND NUTRIENTS CYCLE
Which of the following statements accurately reflects the differences between Batesian mimicry and Müllerian mimicry? A. In Batesian mimicry the model must behave differently than the mimic; in Müllerian mimicry they behave the same. B. In Batesian mimicry the model must be more dangerous than the mimic; in Müllerian mimicry they are both dangerous. C. Batesian mimicry does not differ from Müllerian mimicry. Two different scientists discovered these two types at the same time, and they disagreed on what to call it. D. Batesian mimicry differs from Müllerian mimicry in that they occur on different continents—Batesian on the North American and Müllerian on the European. E. Batesian mimicry involves invertebrates; Müllerian mimicry involves vertebrates.
B. In Batesian mimicry the model must be more dangerous than the mimic; in Müllerian mimicry they are both dangerous.
The scarcity of which two elements limits plant growth? A. oxygen, nitrogen B. nitrogen, phosphorus C. oxygen, phosphorus D. carbon, nitrogen E. carbon, phosphorus
B. NITROGEN, PHOSPHOROUS
Which one of the following ecosystems is most likely to show an inverted biomass pyramid but a normal energy pyramid? A. grassland B. open ocean C. intertidal D. tropical forest E. desert
B. OPEN OCEAN
Warning coloration, serves to protect an animal or plant by sending a warning signal to potential ________ A. competitors. B. predators. C. mates. D. rivals.
B. PREDATORS
The honey possum (Tarsipes rostratus) is a tiny Australian marsupial and one of the very few entirely nectarivorous mammals. Which of the following terms describes the role of a honey possum in its ecosystem? A. primary producers B. primary consumers C. secondary consumers D. secondary producers E. decomposers
B. PRIMARY CONSUMERS
In an aquatic ecosystem, a secondary carnivore is temporarily excluded and then, after a period of time, is returned. Which one of the following is not an expected top-down effect after it is returned? A. Primary carnivores become less abundant. B. Primary productivity increases. C. Algae decrease. D. Herbivores become more abundant. E. Secondary carnivore biomass increases.
B. PRIMARY PRODUCTIVITY INCREASES
The actual niche the organism is able to occupy in the presence of competitors is called its A. fundamental niche. B. realized niche. C. interference niche. D. intraspecific niche. E. exploitative niche.
B. REALIZED NICHE
Competition shapes communities because there are usually limited A. species. B. resources. C. interactions. D. nutrients.
B. RESOURCES
Chemicals that play the dominant role in protecting plants from being eaten by herbivores or predators are called A. primary compounds. B. secondary compounds. C. poisons. D. oils. E. amino acids.
B. SECONDARY COMPOUNDS
The difference in the fundamental niche and the realized niche is A. the fundamental niche is the actual niche that a species occupies while the realized niche is the potential area that the species is capable of inhabiting. B. the fundamental niche is the entire niche that a species is capable of using while the realized niche is just what is being occupied. C. the fundamental niche is smaller than the realized niche. D. the realized niche is theoretical while the fundamental niche is the entire niche that an organism can use.
B. the fundamental niche is the entire niche that a species is capable of using while the realized niche is just what is being occupied.
An unprotected species resembling others that are distasteful is an example of which type of mimicry? A. Müllerian B. competitive C. Batesian D. aposematic
C. BATESIAN
In a food chain with four trophic levels, what would be the energy in the top trophic level if the energy contained in the primary producer level is 40,000 kcal/m2/yr? Assume a trophic level transfer efficiency of 10%. A. 4,000 kcal/m2/yr B. 400 kcal/m2/yr C. 40 kcal/m2/yr D. 4 kcal/m2/yr E. 0.4 kcal/m2/yr
C. C. 40 kcal/m2/yr
Adaptation that enables organisms to blend into their environment thereby avoiding predation. A. coevolution B. defensive coloration C. camouflage D. secondary chemical compounds E. Batesian mimicry
C. CAMOFLAGE
You have been studying the relationship between jackals and tigers in India. Until recently, the only relationship you have observed is that jackals will attach themselves to a particular tiger and follow it at a safe distance in order to feed on the big cat's kills. However, recently you observed a jackal alerting a tiger to a kill with a loud cry. If you continue to observe this alerting behavior, you might change the categorization of the jackal/tiger relationship from ___________ to __________________. A. mutualism; parasitism B. mutualism; commensalism C. commensalism; mutualism D. parasitism; mutualism E. competition; predation
C. COMMENSALISM; MUTUALISM
The attempt of two organisms trying to utilize the same resource is called A. synergy. B. parasitism. C. competition. D. interference.
C. COMPETITION
Which one of the following explanations for why the tropics have greater species diversity than the temperate zone is least convincing? A. Seasonality variability is less in the tropics. B. Niches are narrower in the tropics. C. Fewer predators in the tropics allow more prey species to flourish. D. Greater spatial heterogeneity in the tropics creates more niches. E. The tropics have greater plant production, which supports greater overall species richness.
C. FEWER PREDATORS IN THE TROPICS ALLOW MORE PREY SPECIES TO FLOURISH
Which one of the following quantities best represents the respiratory heat lost by plants in an ecosystem? A. gross primary productivity B. net primary productivity C. gross primary productivity - net primary productivity D. gross primary productivity - standing crop biomass E. gross primary productivity - secondary productivity
C. GROSS PRIMARY PRODUCTIVTY - NET PRIMARY PRODUCTIVITY
Two or more unrelated but protected species resembling each other and achieving a kind of group defense is an example of what type of mimicry? A. Batesian B. disruptive C. Müllerian D. cooperative
C. MULLERIAN
A relationship in which both members benefit is called A. predation. B. parasitism. C. mutualism. D. commensalism. E. sympatric.
C. MUTURALISM
In an ecosystem, the amount of organic matter produced in a given time that is available for heterotrophs is known as A. daily yield. B. gross primary productivity. C. net primary productivity. D. effective vitality. E. net yield.
C. NET PRIMARY PRODUCTIVITY
Over tropical rainforest areas, approximately 90% of the water that reaches the atmosphere comes from A. animal metabolism. B. animal perspiration. C. plant transpiration. D. plant absorption. E. plant metabolism.
C. PLANT TRANSPIRATION
A wolf that feeds on moose and elk would be classified within which trophic level? A. decomposer B. primary producer C. primary carnivore D. secondary carnivore E. detritivore
C. PRIMARY CARNIVORE
Communities evolve to have greater biomass and species richness in a process called A. sympatric interactions. B. adaptive modifications. C. succession. D. symbiotic relationships. E. competitive exclusion.
C. SUCCESSION
Which statement is an accurate interpretation of the outcome in an ecosystem when a major predator is removed? A. The remaining community adjusts and quickly becomes stable. B. The diversity of the ecosystem actually increases. C. The diversity of the ecosystem decreases since there is an increase in competition. D. The diversity of the ecosystem decreases because parasites become more of a problem. E. The diversity of the ecosystem decreases because new herbivores move in.
C. THE DIVERSITY OF THE ECOSYSTEM DECREASES SINCE THERE IS AN INCREASE IN COMPETITION.
The upper, unconfined portion of the groundwater which flows into streams and is partly accessible to plants is called the ____ A. aquifer. B. hydrozone. C. water table. D. watershed.
C. WATER TABLE
Is the process by which different kinds of organisms adjust to one another by genetic change over long periods of time. A. coevolution B. defensive coloration C. camouflage D. secondary chemical compounds E. Batesian mimicry
COEVOLUTION
Which of the following are types of symbioses? Check all that apply. ____ Batesian mimicry ____ commensalism ____ predation ____ parasitism ____ mutualism ____ Müllerian mimicry
COMMENSALISM PARASITISM MUTUALISM
Which of the following are true statements about the carbon cycle? Check all that apply. ____ Carbon and nitrogen fixation are both faciliated by microbes. ____ Burning of gasoline is a contributor to the current imbalance in the carbon cycle. ____ Replacing rainforest with farms decreases atmospheric CO2 levels. ____ In water, inorganic carbon exists in two different forms, both of which can be used by autotrophs. ____ Carbon cycles locally.
Carbon and nitrogen fixation are both faciliated by microbes. Burning of gasoline is a contributor to the current imbalance in the carbon cycle. In water, inorganic carbon exists in two different forms, both of which can be used by autotrophs.
During the mid 1930s, G. F. Gause studied competition among three species of Paramecium. Through his experiments he formulated a principle of A. niche overlap. B. exploitative competition. C. metapopulation fluctuation. D. competitive exclusion. E. interspecific competition.
D. COMPETITIVE EXCLUSION
The carbon cycle is based on carbon dioxide. CO2 makes up about A. 30% of the atmosphere. B. 3% of the atmosphere. C. 0.3% of the atmosphere. D. 0.03% of the atmosphere. E. 0.003% of the atmosphere.
D. 0.03% OF THE ATMOSPHERE
In a food chain consisting of four trophic levels, if the energy present in the top level is 48 kcal/m2/yr, how much energy do you expect in primary consumers? (Use an energy transfer rate of 10%.) A. 4.8 kcal/m2/yr B. 48 kcal/m2/yr C. 480 kcal/m2/yr D. 4,800 kcal/m2/yr E. 48,000 kcal/m2/yr
D. 4,800 kcal/m2/yr
Heterotrophs must obtain organic molecules that have been synthesized by A. biogeochemical cycles. B. bacteria. C. decomposers. D. autotrophs.
D. AUTOTROPHS
Two species of warblers colonize the same island habitat. Both species nest in similar locations and eat the same type of prey. Eventually, competition will probably cause one species to A. migrate. B. grow exponentially. C. speciate. D. be eliminated.
D. BE ELIMINATED
Organisms that possess this property are poisonous, sting, or are otherwise harmful; commonly black, yellow, and red in color. A. coevolution B. defensive coloration C. camouflage D. secondary chemical compounds E. Batesian mimicry
D. DEFENSIVE COLORATION
Insects that lay eggs on living hosts are called A. ectoparasites. B. endoparasites. C. brood parasites. D. parasitoids. E. predators.
D. PARASITOIDS
Energy enters most ecosystems by the process of A. biosynthesis. B. respiration. C. biogeochemical weathering. D. photosynthesis. E. fermentation.
D. PHOTOSYNTHESIS
Which one of the links in the food chain shown below does the garden spider represent? grass—cricket—garden spider—blue jay—red-tailed hawk A. detritivore B. primary producer C. primary consumer D. secondary consumer E. tertiary consumer
D. SECONDARY CONSUMER
A Viceroy caterpillar feeds on a leaf. If a day's feeding gains the caterpillar a total of 1000 calories and 50% is lost in its feces and 33% of the energy is used through cellular respiration, how many calories of the original intake are available for caterpillar biomass? A. 830 calories B. 670 calories C. 500 calories D. 330 calories E. 170 calories
E. 170 CALORIES
Chemical defenses are found in all of the following except A. marine animals. B. insects. C. plants. D. snakes, spiders, and fishes. E. Batesian mimics.
E. BATESIAN MIMICS
In India, golden jackals that have been expelled from their pack have been known to attach themselves to a particular tiger, trailing it at a safe distance in order to feed on the big cat's kills. What type of relationship exists between the jackal and the tiger? A. mutualism B. predation C. parasitism D. competition E. commensalism
E. COMMENSALISM
Which of the following groups do not contain any species that are autotrophs? A. Bacteria B. Protista C. Plants D. Archaea E. Fungi
E. FUNGI
The way in which an organism utilizes its environment may be called A. resource partitioning. B. its habitat. C. competitive exclusion. D. intraspecific competition. E. its niche.
E. ITS NICHE
The form of nitrogen most likely to be absorbed from the soil by plants is A. nitrogenous wastes. B. nucleic acids. C. nitrogen gas. D. nitrous oxide gas. E. nitrite/nitrate ions.
E. NITRATE/ NITRITE IONS
With almost no exceptions, the nitrogen fixers are A. beans. B. green plants. C. insects. D. mammals. E. prokaryotes.
E. PROKARYOTES
Which one of the links in the food chain shown below does the blue jay represent? grass—cricket—garden spider—blue jay—red-tailed hawk A. detritivore B. primary producer C. primary consumer D. secondary consumer E. tertiary consumer
E. TERTIARY CONSUMER
True False Resource partitioning would be most likely to occur between allopatric populations of species with similar ecological niches.
FALSE
True False Solar energy is the same thing as heat energy.
FALSE
In which of the following ways does species richness affect ecosystem function? Check all that apply. ____ Low species richness can contribute to ecosystem stability. ____ High species richness can increase ecosystem resistance to drought. ____ Low species richness can make an ecosystem more susceptible to invasive species. ____ High species richness reduces overall ecosystem productivity.
HIGH SPECIES RICHNESS CAN INCREASE ECOSYSTEM RESISTANCE TO DROUGHT. LOW SPECIES RICHNESS CAN MAKE AN ECOSYSTEM MORE SUSCEPTIBLE TO INVASIVE SPECIES.
Which of the following would be an expected long-term change during primary succession on glacial moraines? Check all that apply. ____ increase in species richness ____ decrease in soil depth ____ increase in soil salinity ____ increase in soil nitrogen ____ alder replaced by spruce
INCREASE IN SPECIES RICHNESS INCREASE IN SOIL NITROGEN ALDER REPLACED BY SPRUCE
Which of the following statements about mimicry are true? Check all that apply. ____ Generally, the number of mimics in a Müllerian mimicry system must be less than the number of models ____ Only Batesian mimicry depends on the ability of the predator to learn. ____ In Müllerian mimicry, the participants are both mimics and models. ____ In Batesian mimicry, the participants are either mimics or models. ____ A Müllerian mimic is "a sheep in wolf's clothing".
In Müllerian mimicry, the participants are both mimics and models. In Batesian mimicry, the participants are either mimics or models.
Following their respective breeding seasons, several species of hummingbirds occur at the same locations in North America and several hummingbird flowers bloom simultaneously in these habitats. These flowers seem to have converged to a common morphology and color. Birds are most visually sensitive to the color red. Hummingbird flowers are pollinated by hummingbirds. Which of the following features of these flowers would indicate they have coevolved with hummingbirds? ____ long tubular flowers ____ flowers are colored violet and blue ____ blooming time of the flowers coincides with the arrival of the hummingbirds ____ flowers produce a high volume of nectar and sugar ____ flowers are low to the ground
LONG TUBULAR FLOWERS BLOOMING TIME OF THE FLOWERS COINCIDES WITH THE ARRIAL OF HUMMINGBIRDS FLOWERS PRODUCE A HIGH VOLUME OF NECTAR AND SUGAR
Which of the following factors would influence the productivity of an aquatic community? Check all that apply. ____ nitrogen-fixing bacteria ____ seasonality ____ the number of autotrophs ____ a limiting nutrient ____ the amount of rainfall
NITROGEN-FIXING BACTERIA SEASONALITY A NUMBER OF AUTOTROPHS A LIMITING NUTRIENT
Phosphorus deficiency often appears early in plant growth and results in stunting. Which of the following are reasons why a deficiency in phosphorus would cause growth abnormalities in plants? ____ Phosphorus is required for the storage and transfer of energy. ____ Phosphorus is required for the production of amino acids and the synthesis of proteins. ____ Phosphorus is required for DNA replication. ____ Phosphorus is necessary for building cellular structures responsible for regulating the flow of compounds into and out of a cell. ____ Without phosphorus, cellular division is impeded.
Phosphorus is required for the storage and transfer of energy. Phosphorus is required for DNA replication. Phosphorus is necessary for building cellular structures responsible for regulating the flow of compounds into and out of a cell. Without phosphorus, cellular division is impeded.
Which of the following statements about symbiotic relationships are true? Check all that apply. ____ Plant-pollinator interaction is a good example of mutualism. ____ Both mutualisms and commensalisms result from the process of coevolution. ____ It is sometimes difficult to determine if a specific relationship is mutualism, commensalism, or parasitism. ____ Parasites can sometimes influence the behavior of their hosts to facilitate completion of their life cycles. ____ Mutualists sometimes become parasites.
Plant-pollinator interaction is a good example of mutualism. It is sometimes difficult to determine if a specific relationship is mutualism, commensalism, or parasitism. Parasites can sometimes influence the behavior of their hosts to facilitate completion of their life cycles. Mutualists sometimes become parasites.
Which of the following observations were an outcome of studies by David Tilman and coworkers at Cedar Creek, Minnesota on ecosystem stability? Check all that apply. ____ Plots with more species showed less year-to-year variation in biomass. ____ Species-rich plots were less affected by drought than species-poor plots. ____ Over-yielding was observed in more recent work at Cedar Creek. ____ Nitrogen uptake and total biomass produced were negatively correlated to species richness. ____ More diverse plots were less susceptible to invasion by new species.
Plots with more species showed less year-to-year variation in biomass. Species-rich plots were less affected by drought than species-poor plots. Over-yielding was observed in more recent work at Cedar Creek. More diverse plots were less susceptible to invasion by new species.
Which of the following statements about predation are true? Check all that apply. ____ Predation reduces competition in a community. ____ Removal of a predator often leads to increased community stability. ____ Animal predation on plants is called herbivory. ____ Predation can induce coevolutionary changes in prey species. ____ Batesian mimicry is not a coevolutionary adaptation to predation.
Predation reduces competition in a community. Animal predation on plants is called herbivory. Predation can induce coevolutionary changes in prey species.
Which of the following factors could be important in determining a species' fundamental niche? Check all that apply. ____ salinity ____ presence of a commensalist ____ soil type ____ presence of a predator/parasite ____ seasonal temperatures
SALINITY SOIL TYPE SEASONAL TEMPERATURES
Forests, like other ecological systems, are subject to the species succession process. Which of the following would be characteristics of pioneer plant species facilitating the early stages of forest succession? ____ slow-growing ____ pollinated by animals ____ seedling growth requires direct sunlight ____ seeds germinate in the shade ____ plants produce great quantity of seeds
SEEDLING GROWTH REQUIRES DIRECT SUNLIGHT PLANTS PRODUCE GREAT QUANTITY OF SEEDS
Communities with a high level of bacterial diversity are found in many habitats including soil and aquatic environments. Recent studies indicate this diversity is crucial to the functioning of these communities. The same studies have also found that phage abundance plays a critical role in the maintenance of the bacterial diversity within these communities. What is the probable role of phages in this community? ____ they act as facilitators ____ they have a mutualistic relationship with the bacteria ____ they parasitize the bacteria ____ they have a commensal relationship with the bacteria ____ they compete with the bacteria for space and nutrients
THE PARASITIZE THE BACTERIA
True False In general, communities in early succession will be dominated by fast-growing species with r-selected life histories.
TRUE
True False Interspecific competition can affect the phenotypic characteristics of organisms.
TRUE
True False Mimicry is a form of camouflage.
TRUE
In studies of two species of barnacles in the marine intertidal zone it was observed that Chthamalus can live in the upper intertidal zone and the lower intertidal zone if Semibalanus is absent, and Semibalanus can only live in the lower zone because it is more subject to dehydration. Based on this, which of the following statements are true? Check all that apply. ____ The realized niches of the two species differ. ____ The fundamental niche of Chthamalus is larger than its realized niche. ____ The fundamental niche of Chthamalus is larger than the fundamental niche of Semibalanus. ____ The fundamental and the realized niches of Chthamalus are the same. ____ The fundamental and the realized niches of Semibalanus are the same.
The realized niches of the two species differ. The fundamental niche of Chthamalus is larger than its realized niche. The fundamental niche of Chthamalus is larger than the fundamental niche of Semibalanus. The fundamental and the realized niches of Semibalanus are the same.
Which of the following are true about ecosystems? Check all that apply. ____ They contain both living and nonliving components. ____ There is a transfer of energy through the system and some energy is lost as heat energy. ____ Nutrients repeatedly cycle through the ecosystem. ____ They represent the lowest level of biological organization. ____ The ultimate source of energy for most ecosystems is the sun.
They contain both living and nonliving components. There is a transfer of energy through the system and some energy is lost as heat energy. Nutrients repeatedly cycle through the ecosystem. The ultimate source of energy for most ecosystems is the sun.
Which of the following examples would be undergoing secondary succession? Check all that apply. ____ an abandoned potato farm ____ a coastal grassland damaged by a hurricane ____ an abandoned landfill ____ rocks in a national park covered by mosses and lichens ____ a garden bed that has been weeded
an abandoned potato farm a coastal grassland damaged by a hurricane an abandoned landfill a garden bed that has been weeded