Lesson 3 (Chapter 55, Ecosystems Ecology) Flashcards
all the organisms living in a community, as well as the abiotic factors with which they interact
ecosystem
an ecosystem’s dynamics involve these two main processes, regardless of its size
energy flow, chemical cycling
scientists who study the transformations of energy and matter within ecosystems
ecologists
laws that apply to ecosystems
laws of physics, laws of chemistry
states that energy cannot be created or destroyed, only transformed
first law of thermodynamics
application of first law of thermodynamics in an ecosystem
energy enters an ecosystem as solar radiation, is conserved, and is lost from organisms through heat
states that every exchange of energy increases the entropy of the universe
second law of thermodynamics
application of second law of thermodynamics in an ecosystem
in an ecosystem, energy conversions are not completely efficient, and some energy is always lost as heat
states that matter cannot be created nor destroyed
law of conservation of mass
application of law of conservation of mass in an ecosystem
chemical elements are continually recycled within ecosystems
systems that absorbing energy and mass and releasing heat and waste products
open systems such as ecosystems
organisms that build molecules themselves using photosynthesis or chemosynthesis as an energy source
autotrophs
organisms that depend on the biosynthetic output of other organisms
heterotrophs
also known as primary producers
autotrophs
also known as primary consumers
herbivores
also known as secondary consumers
herbivore-eating carnivores
also known as tertiary consumers
carnivore-eating carnivores
also known as decomposers, consumers that derive their energy from detritus
detritivores
nonliving organic matter
detritus
examples of important detritivores
prokaryotes, fungi
process that connects all trophic levels
decomposition
amount of light energy converted to chemical energy by autotrophs during a given time period
primary production
the primary producers in a few ecosystems
chemoautotrophs
what sets the spending limit for an ecosystem’s energy budget
extent of photosynthetic production
what sets the limit of photosynthetic output of ecosystems
amount of solar radiation reaching Earth’s surface
true or false: only a small fraction of solar energy actually strikes photosynthetic organisms, and even less is of a usable wavelength
true
total primary production of an ecosystem
gross primary production
formula for gross primary production
conversion of chemical energy from photosynthesis per unit time
gross primary production minus energy used by primary producers for respiration
net primary production
formula for net primary production
gross primary production minus energy used by primary producers for respiration
ways to express net primary production
energy per unit area per unit time
biomass added per unit area per unit time
indication of net primary production
amount of new biomass added in a given time period
true or false: only net primary production is available to consumers
true
the total biomass of photosynthetic autotrophs at a given time
standing crop
areas that are among the most productive ecosystems per unit area
tropical rain forests, estuaries, coral reefs
significance of marine ecosystems
relatively unproductive per unit area but contribute much to global net primary production because of their volume
a measure of the total biomass accumulation during a given period
net ecosystem production
formula for net ecosystem production
gross primary production minus the total respiration of all organisms in an ecosystem
how to estimate net ecosystem production
comparing the net flux of CO2 and O2 in an ecosystem
significance of the release of O2 by a system
indication that a system is also storing CO2
two factors that control primary production in marine and freshwater ecosystems
light, nutrients
factor that affects primary production in the photic zone of an ocean or lake
depth of light penetration
the element that must be added for production to increase in an area
limiting nutrients
the two nutrients that most often limit marine production
nitrogen, phosphorus
limiting nutrient in the phytoplankton growth off the shore of Long Island, New York
nitrogen
limiting nutrient in the phytoplankton growth off the shore of the Sargasso Sea in the subtropical Atlantic Ocean
iron
contributes to regions of high primary production
upwelling of nutrient-rich waters
excessive plant and algal growth
eutrophication
cause of eutrophication in some areas
sewage runoff
effect of eutrophication
loss of most fish species
limiting nutrient of cyanobacterial growth in lakes
phosphorus
why phosphate-free detergents are used
to limit eutrophication of cyanobacteria due to sewage runoff
two factors that affect primary production of terrestrial ecosystems on a large scale
temperature, moisture
true or false: primary production increases with moisture
true
the water transpired by plants and evaporated from a landscape
actual evapotranspiration
factors that affect evapotranspiration
precipitation, temperature, solar energy
true or false: actual evapotranspiration is not related to net primary production
false
what is often a limiting factor in primary production on a more local scale
a soil nutrient
the most common limiting nutrient in terrestrial ecosystems
nitrogen
another common limiting in terrestrial ecosystems, especially in older soils
phosphorus
examples of adaptations that help plants in accessing limiting nutrients from soil
some form mutualisms with nitrogen-fixing bacteria
many form mutualisms with mycorrhizal fungi, which supply phosphorus and other limiting elements
have root hairs that increase surface area
many release enzymes that increase the availability of limiting nutrients
the amount of chemical energy in food converted to new biomass during a given period of time
secondary production
the fraction of energy stored in food that is not used for respiration
production efficiency
formula of production efficiency
[net secondary production ÷ assimilation of primary production] × 100
production of efficiency of birds and mammals
1-3%
production of efficiency of fish
10%
production of efficiency of insects and microorganisms
40% or more
the percentage of production transferred from one trophic level to the next
trophic efficiency
usual range of trophic efficiency
between 5% to 20%, usually about 10%
amount of chemical energy fixed by photosynthesis that reaches a tertiary consumer
approximately 0.1%
represents the loss of energy with each transfer in a food chain
pyramid of net production
what does each tier of a biomass pyramid represent
the dry mass of all organisms in one trophic level
where do most biomass pyramids show a sharp decrease
at successively higher trophic levels
certain aquatic ecosystems have this kind of biomass pyramid
inverted biomass pyramid
implication of inverted biomass pyramids
primary producers are consumed so quickly that they are outweighed by primary consumers
the ratio of the standing crop biomass to production
turnover time
true or false: dynamics of energy flow in ecosystems have important implications for the human population
true
what is the problem with eating meat
it is a relatively inefficient way of tapping photosynthetic production
true or false: worldwide agriculture could feed many more people if humans ate only plant material
true
true or false: life does not depend on recycling chemical elements
false
nutrient cycles in ecosystems involving biotic and abiotic components
biogeochemical cycles
most commonly occurring gases in the atmosphere which cycle globally
gaseous carbon, oxygen, sulfur, nitrogen
less mobile elements available in the ecosystem
phosphorus, potassium, calcium
difference between terrestrial systems and aquatic systems in terms of nutrient cycling
elements cycle locally in terrestrial systems but more broadly when dissolved in aquatic systems
includes main reservoirs of elements and processes that transfer elements between reservoirs
model of nutrient cycling
true or false: all elements cycle between organic and inorganic reservoirs
true
four factors ecologists focus on when studying cycling of water, carbon, nitrogen, and phosphorus
each chemical’s biological importance
forms in which each chemical is available or used by organisms
major reservoirs for each chemical
key processes driving movement of each chemical through its cycle
an essential to all organisms
water
the primary physical phase in which water is used
liquid water
percentage of the biosphere’s water contained in the oceans
97%
percentage of the biosphere’s water contained in glaciers and polar ice caps
2%
percentage of the biosphere’s water contained in lakes, rivers, and groundwater
1%
cycle depicting the movement of water by the processes of evaporation, transpiration, condensation, precipitation, and movement through surface and groundwater
water cycle
essential to all organisms
carbon-based organic molecules
significance of photosynthetic organisms
convert CO2 to organic molecules that are used by heterotrophs
examples of carbon reservoirs
fossil fuels, soils and sediments, solutes in oceans, plant and animal biomass, the atmosphere, sedimentary rocks, volcanoes
cycle depicting the movement of CO2 in which it is taken up through photosynthesis and released through respiration
carbon cycle
a component of amino acids, proteins, and nucleic acids
nitrogen
the main reservoir of nitrogen and its most common form
atmosphere, atmospheric nitrogen (N2)
forms of nitrogen that can be consumed by plants
NH4+, NO3-
how N2 gets converted into NH4+ or NO3-
nitrogen fixation by bacteria
process in which organic nitrogen is decomposed to NH4+
ammonification
process in which NH4+ is decomposed to NO3-
nitrification
process in which NO3- is converted back to N2
denitrification
a major constituent of nucleic acids, phospholipids, and ATP
phosphorus
the most important inorganic form of phosphorus
phosphate ([PO4]3-)
largest reservoirs of phosphorus
sedimentary rocks of marine origin, the oceans, and organisms
process in which phosphate binds with soil particles, localizing its movement
phosphorus cycle
play a key role in the general pattern of chemical cycling
decomposers or detritivores
effect of differing rates of decomposition
great variation between the rates at which nutrients cycle in different ecosystems
factors affecting the rate of decomposition
temperature, moisture, nutrient availability
effect of rapid decomposition
relatively low levels of nutrients in the soil
area wherein rapid decomposition occurs
tropical rain forest
effect of slow decomposition
large amounts of undecomposed organic matter
areas wherein slow decomposition occurs
cold and wet ecosystems, anaerobic muds
used to study nutrient cycling in a forest ecosystem since 1963
Hubbard Brook Experimental Forest
findings on water loss in undisturbed site
60% of precipitation exits through streams and 40% is lost by evapotranspiration
findings on water loss in deforested site
net losses of water were 30% - 40% greater compared to the loss in the undisturbed site
effect of deforestation on nutrient levels
nutrient loss was much greater than in the undisturbed site
seeks to initiate or speed up the recovery of degraded ecosystems
restoration ecology
two key strategies of restoration ecology
bioremediation, augmentation of ecosystem processes
the use of organisms to detoxify ecosystems
bioremediation
organisms often used in bioremediation, which can take up or sometimes metabolize toxic molecules
prokaryotes, fungi, plants
can metabolize uranium and other elements to insoluble forms that are less likely to leach into streams and groundwater
Shewanella oneidensis
uses organisms to add essential materials to a degraded ecosystem
biological augmentation
examples of biological augmentation
using nitrogen fixing plants to increase available nitrogen in soil
adding mycorrhizal fungi to help plants access nutrients from soil
how to successfully conduct restoration projects
consider alternative solutions and adjust approaches based on experience
