bio exam 2 chapter 55 w/o diagrams
Acid precipitation lowered the pH of soil in a terrestrial ecosystem that supported a diverse community of plants and animals. The decrease in pH eliminated all nitrogenfixing bacteria populations in the area. Which prediction most accurately reflects the impact this will have on the community? -The decrease in pH actually increases the availability of soil nutrients, so other nutrients that were less available cause an increase in primary production and an increase in biomass at other trophic levels. -Primary producers will suffer from nitrogen deficiency and the entire community will experience a decrease in carrying capacity. -Plants can obtain the nitrogen necessary for growth from the atmosphere, but bacterial communities will be negatively impacted. -Since phosphorus can replace nitrogen as an essential nutrient, the impact will be minimal.
Primary producers will suffer from nitrogen deficiency and the entire community will experience a decrease in carrying capacity.
Why is terrestrial productivity higher in equatorial climates? -Productivity increases with temperature. -Productivity increases with water availability. -Productivity increases with available sunlight. -The answer is most likely a combination of the other responses.
The answer is most likely a combination of the other responses.
How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top-level predators? -Top-level predators are more likely to be stricken with parasites. -Predators are more disease-prone than animals at lower trophic levels. -Top-level predators are destined to have small populations that are sparsely distributed. -Predators have relatively large population sizes.
Top-level predators are destined to have small populations that are sparsely distributed.
How do pyramids of net production and pyramids of biomass differ? -Pyramids of net production include fewer trophic levels than pyramids of biomass. -Unlike pyramids of net production, the shape of a pyramid of biomass varies with the size of the organisms in the ecosystem. -Unlike pyramids of biomass, pyramids of net production are based on measurements per unit time.
Unlike pyramids of biomass, pyramids of net production are based on measurements per unit time.
Which of these ecosystems has the lowest net primary production per square meter? an open ocean a tropical rain forest a salt marsh a grassland a coral reef
an open ocean
For most terrestrial ecosystems, pyramids composed of species abundances, biomass, and energy are similar in that they have a broad base and a narrow top. The primary reason for this pattern is that _____. -top carnivores and secondary consumers have a more general diet than primary producers -biomagnification of toxic materials limits the secondary consumers and top carnivores -secondary consumers and top carnivores require less energy than producers -at each step, energy is lost from the system
at each step, energy is lost from the system
How is net ecosystem production (NEP) typically estimated in ecosystems? -by detecting the amount of heat energy released by the ecosystem -by calculating the annual total of incoming solar radiation per unit of area -by measuring the rate of decomposition by detritivores -by measuring gas exchange from vegetation as well as estimates of respiration by all other organisms
by measuring gas exchange from vegetation as well as estimates of respiration by all other organisms
An ecosystem is unlikely to be limited by the supply of _____ because it is obtained from the air. See Concept 55.4 ( page 1246) Hints water carbon phosphorus calcium nitrogen
carbon
If the sun were to suddenly stop providing energy to Earth, most ecosystems would eventually vanish. Which of the following ecosystems would likely survive the longest after this hypothetical disaster? -tundra -pelagic ocean -deep benthic ocean -a desert spring
deep benthic ocean
Many of the organisms in the ocean are nutrient-limited. If you wanted to investigate this phenomenon, one reasonable approach would be to ________. -contrast nutrient uptake by autotrophs in marine locations that are different temperatures -compare nutrient concentrations between the photic zone and the benthic zone in various marine locations -observe Antarctic Ocean productivity from year to year to see if it changes -experimentally enrich some areas of the ocean and compare their productivity to that of untreated areas
experimentally enrich some areas of the ocean and compare their productivity to that of untreated areas
On a global scale, energy _____ ecosystems whereas chemical elements _____ ecosystems. See Concept 55.1 ( page 1237) Hints -is biologically magnified in ... are recycled in -is dissipated in ... flow through flows through ... are recycled in -is continuously supplied to ... are continuously removed from -is recycled in ... flow through
flows through ... are recycled in
Which of the following ecosystems would likely have the largest net primary productivity per hectare and why? -tundra, because of the incredibly rapid period of growth during the summer season -deep ocean, due to the high activity of chemoautotrophs at deep sea vents -open ocean, because of the total biomass of photosynthetic autotrophs -grassland, because of rapid growth, the small standing crop biomass that results from consumption by herbivores, and rapid decomposition
grassland, because of rapid growth, the small standing crop biomass that results from consumption by herbivores, and rapid decomposition
What is the single greatest threat to biodiversity? -overharvesting of commercially important species -novel pathogens -habitat alteration, fragmentation, and destruction -introduced species that compete with native species
habitat alteration, fragmentation, and destruction
Which of the following terms encompasses all of the others? herbivores primary consumers carnivores heterotrophs
heterotrophs
Biogeochemical cycles are crucial to ecosystem function because _____. See Concept 55.4 ( page 1246) Hints -they keep the planet warm enough for living things to survive -nutrients and other life-sustaining molecules are in limited supply and must be continually recycled -energy flows through ecosystems in one direction only and is eventually dissipated as heat -they remove poisons and keep them locked up in "sinks" -they prevent catastrophic extinctions
nutrients and other life-sustaining molecules are in limited supply and must be continually recycled
How can biodiversity affect the way we decontaminate industrial sites? I) Bacteria have been found to be able to detoxify certain chemicals; perhaps there are more. II) Trees produce sawdust, which can be used to soak up chemicals. III) Species evolving in contaminated areas could adapt and detoxify the area. only I only II only III only II and III
only I
The Hubbard Brook watershed deforestation experiment revealed that _____. I) deforestation increased water runoff II) nitrate concentration in waters draining the deforested area became dangerously high III) calcium levels remained high in the soil of deforested areas only I only II only III only I and II
only I and II
Which of the following organisms is correctly paired with its trophic level? -grasshopper: secondary consumer -fungus: primary consumer -cyanobacterium: primary consumer -phytoplankton: primary producer
phytoplankton: primary producer
The relationship between biomass and primary productivity is that _____. See Concept 55.2 ( page 1239) Hints -biomass is the rate of primary productivity -biomass is the inverse of primary productivity -biomass is the natural log of primary productivity -primary productivity is the inverse of biomass -primary productivity is the rate at which biomass is produced
primary productivity is the rate at which biomass is produced
To recycle nutrients, an ecosystem must have, at a minimum, _____. -producers and decomposers -producers, primary consumers, secondary consumers, and decomposers -producers, primary consumers, and decomposers -producers
producers and decomposers
The discipline that applies ecological principles to returning degraded ecosystems to a more natural state is known as _____. -restoration ecology -conservation ecology -landscape ecology -resource conservation
restoration ecology
Which of the following has the greatest effect on the rate of chemical cycling in an ecosystem? -the ecosystem's rate of primary production -the rate of decomposition in the ecosystem -the location of the nutrient reservoirs in the ecosystem -the trophic efficiency of the ecosystem -the production efficiency of the ecosystem's consumers
the rate of decomposition in the ecosystem
Which of the following has the greatest effect on the rate of chemical cycling within an ecosystem? -the secondary production efficiency of the ecosystem's consumers -the ecosystem's rate of primary production -the trophic efficiency of the ecosystem -the rate of decomposition in the ecosystem
the rate of decomposition in the ecosystem
The energy for nearly every organism in nearly every ecosystem ultimately comes from _____. See Concept 55.1 ( page 1237) Hints -minerals in the soil -the sun -heat from Earth -respiration -decomposition
the sun
Which of the following organisms is incorrectly paired with its trophic level? -grasshopper-primary consumer -cyanobacterium-primary producer -eagle-tertiary consumer -fungus-detritivore -zooplankton-primary producer
zooplankton-primary producer
The producers in aquatic ecosystems include organisms in which of the following groups? See Concept 55.2 ( page 1240) Hints -cyanobacteria -algae -plants -photoautotrophs -All of the above are correct.
All of the above are correct.
Why is it that nitrogen is often a limiting plant nutrient, despite the fact that the atmosphere is 80% nitrogen gas (N2)? -Because N2 easily leaches away from soil -Because plants cannot fix N2 -Because plants cannot assimilate nitrogen-containing compounds
Because plants cannot fix N2
If you applied a fungicide to a cornfield, what would you expect to happen to the rate of decomposition and net ecosystem production (NEP)? -Both decomposition rate and NEP would increase. -Both decomposition rate and NEP would decrease. -Decomposition rate would increase and NEP would decrease. -Decomposition rate would decrease and NEP would increase.
Decomposition rate would decrease and NEP would increase.
Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems? -Energy transfer between trophic levels is usually less than 20 percent efficient. -Nutrient cycling rates tend to be limited by decomposition. -Many primary and higher-order consumers are opportunistic feeders. -Decomposers compete with higher-order consumers for nutrients and energy.
Energy transfer between trophic levels is usually less than 20 percent efficient.
Matter may be gained by, or lost from, ecosystems. How does this occur? -Chemoautotrophic organisms can convert matter to energy. -Photosynthetic organisms convert solar energy to sugars. -Matter can move from one ecosystem to another. -Heterotrophs convert heat to energy.
Matter can move from one ecosystem to another.
Why is a diagram of energy flow from trophic level to trophic level shaped like a pyramid? See Concept 55.3 ( page 1244) Hints -Organisms at each level store most of the energy and pass little on. -There are more producers than primary consumers, and so on. -Organisms eventually die. -Most energy at each level is lost, leaving little for the next. -Secondary consumers are larger than primary consumers, and so on.
Most energy at each level is lost, leaving little for the next.
Which of the following equations is correct? See Concept 55.2 ( page 1239) Hints -NPP = GPP − R -R = NPP + GPP -GPP = NPP − R -NPP = GPP + R -NPP = GPP/R
NPP = GPP − R
Which of the following is an accurate statement regarding mineral nutrients in soils and their implication for primary productivity? -Adding a nonlimiting nutrient will stimulate primary productivity. -Globally, phosphorous availability is most limiting to primary productivity. -Alkaline soils are more productive than acidic soils. -Phosphorous is sometimes unavailable to producers due to leaching.
Phosphorous is sometimes unavailable to producers due to leaching.