ch55 Flashcards
A measure of the total biomass accumulation during a given period of time is called the _________.
net ecosystem production
A measure of the total primary production in an ecosystem is called the _________.
gross primary production
In a working ecosystem such as the arctic tundra, all of the following exist except _______.
a reduction in the competition for resources
Increased rates of decomposition occur in ________ ecosystems.
tropical
Biological augmentation is a process that _________.
uses organisms to add essential materials to a degraded ecosystem
Detritivores are _________.
heterotrophs
The phosphorus cycle lacks a(n) __________ component.
atmospheric
Which of the following is an ecosystem?
All of the organisms living in your aquarium and the abiotic factors with which they interact
The law of conservation of mass is important in ecology because _________.
it allows scientists to determine the gain or loss of a chemical element in an ecosystem
A measure of production that is calculated by subtracting autotrophic respiration from all primary production in an ecosystem is called _________.
net primary production
The direct product of nitrogen fixation is __________.
NH3
Most of the sunlight that reaches Earth __________.
is not captured for use by living things
Local conditions such as heavy rainfall or the removal of plants may limit the amount of nitrogen, phosphorus, or calcium available to a particular ecosystem, but the amount of carbon available to the system is seldom a problem. Why?
Many nutrients come from the soil, but carbon comes from the air.
The global hydrologic cycle supports a net flow of atmospheric water vapor __________.
from the oceans to land
Bioremediation is a process that _________.
uses organisms to detoxify polluted ecosystems
Which of the following statements is true?
Over oceans, evaporation exceeds precipitation.
The biggest difference between the flow of energy and the flow of chemical nutrients in an ecosystem is that __________.
nutrients are recycled, but energy is not
A study of metabolic rates in a terrestrial community showed that the energy released by respiration exceeded the energy captured in photosynthesis. Which of the following situations is most likely?
Community biomass is decreasing.
Primary producers are _________.
autotrophs
The percentage of production transferred from one trophic level to the next-higher level is called ________.
trophic efficiency
The main decomposers in an ecosystem are __________.
fungi and prokaryotes
Important biogeochemical cycles in ecosystems include all of the following except the ________ cycle.
potassium
The percentage of energy stored in assimilated food that is not used for respiration is the _________.
production efficiency
In an ecosystem, all incoming energy will eventually be __________.
dissipated into space as heat
