Shared Flashcard Set

Details

Ecosystems I Test II
Chapter 6
66
Environmental Studies
Undergraduate 2
11/08/2007

Additional Environmental Studies Flashcards

 


 

Cards

Term
224 billion tons per year
Definition
annual total production of dry plant biomass =
Term
59%
Definition
% of annual plant biomass produced in terrestrial ecosystems
Term
35-40%
Definition
% of terrestrial plant biomass used by humans as food/fiber crops or feed for animals
Term
90%, 10%
Definition
According to Pauly and Christensen, about ___% of consumed energy is used to maintain the consumer, meaning that only ____% is converted through growth and reproduction to biomass, and thus potential food for other organisms.
Term
Charles Elton's contribution (English ecologist of the 1920's)
Definition
Argued that organisms living in the same place not only had similar tolerances of physical factors in the environment but also interacted with one another, most importantly in a system of feeding relationstips that he called a food web.
Term
A.G. Tansley's contribution (English plant ecologist of the 1930's)
Definition
First to consider animals and plants, together with the physical factors of their surroundings, as ecological systems. He called this concept the ecosystem and regarded it as the fundamental unit of ecological organization.
Term
Alfred J. Lotka's contribution (Chemist)
Definition
He developed the first thermodynamic concept of the ecosystem. He was the first to consider populations and communities as energy-transforming systems, and suggested that each system can be described in principle by a set of equations that represent exchanges of matter and energy among its components. (i.e. assimilation of CO2 into organic carbon compounds by plants, consumption of plants by herbivores, and consumption of animals by carnivores.
Term
Lotka's thermodynamic principles
Definition
energy transformations of ecosystems grow in direct proportion to their size, productivity, and inefficiency. earth itself is a giant thermodynamic machine in which the circulation of winds and ocean currents and the evaporation of water are driven by the energy in sunlight. part of that energy is assimilated by the photosynthesis of plants and this energy ultimately fuels all biological systems.
Term
food chain
Definition
sequence of feeding relationships by which energy passes through the ecosystem
Term
Raymond Lindeman's contribution (young aquatic ecologist at U of M)
Definition
brought attention to the concept of the ecosystem as an energy-transforming system in 1942. coined terms "trophic level," "pyramid of energy," and argued that energy is lost at each level because of the work performed by organisms at that level and because of the inefficiency of biological energy transformations.
Term
trophic level
Definition
greek "trophic" = food. link of the food chain, i.e. plant, herbivore, carnivore.
Term
pyramid of energy
Definition
less energy reaches each successively higher trophic level.
Term
ecosystem ecology's conception
Definition
1950's- cycling of matter and associated passage of energy through an ecosystem provides a basis for characterizing that system's structure and function. can compare energy and elements in different ecosystems as common "currency."
Term
Eugene P. Odum's contributions (University of Georgia)
Definition
text "Fundamentals of Ecology," 1953, influenced a generation of ecologists. he depicted ecosystems as energy flow diagrams to convey the principle that energy passes from one trophic level to the next.
Term
light, heat
Definition
energy enters ecosystems as _____ and leaves as _____.
Term
primary production
Definition
when plants, algae, and some bacteria capture light energy and transform it into the energy of chemical bonds in carbohydrates.
Term
photosynthesis equation
Definition
(6)CO2 + (6)H20 -> C6H12O6 + (6)O2
Term
oxidized, reduced
Definition
photosynthesis transforms carbon from a(n) _________ (low-energy) state in CO2 to a _________ (high-energy) state in carbohydrates.
Term
39 kilojoules (kJ)
Definition
for each gram of carbon assimilated, a plant transfers _________ kJ of energy from sunlight to the chemical energy of carbon in carbohydrates.
Term
small, 1/3, heat
Definition
plant pigments that capture the energy of light for photosynthesis actually absorb a ______ fraction of the total incident solar radiation. plants assimilate about ______ of the light energy absorbed by those photosynthetic pigments. the rest is lost as _____.
Term
glucose
Definition
rearranged and joined together, ____ molecules become fats, starches, oils, and cellulose.
Term
proteins, nucleic acids, pigments
Definition
combined with nitrogen, phosphorus, sulfur, and magnesium, simple carbs derived from glucose produce an array of _______, ________ ______, and _______.
Term
gross primary production
Definition
total energy assimilated by photosynthesis
Term
net primary production
Definition
energy accumulated in plants and which is therefore available to consumers
Term
energy of respiration
Definition
amount of energy used by plants for maintenance and biosynthesis. this is the difference between net and gross primary production (gross doesn't subtract this)
Term
carbon
Definition
the energy equivalent of an organic compound depends primarily on its ____ content
Term
39 kJ
Definition
organic compounds contain approximately ___ kJ of metabolizable energy per gram of carbon
Term
amount of plant biomass produced in a year
Definition
in terrestrial ecosystems, ecologists often estimate net production by measuring the amount of _______.
Term
AANP
Definition
aboveground net productivity- most common basis for comparing terrestrial communities
Term
assimilation, respiration
Definition
when a plant is exposed to light, carbon dioxide flux includes both ____ (uptake) and _____ (output), and thus measures net production.
Term
saturation
Definition
for plants growing in full sunlight, light levels usually exceed the ______ pt. of their photosynthetic pigments and is therefore not restricted by light availability
Term
photosynthetic efficiency
Definition
percentage of the energy in sunlight that is converted to net primary production during the growing season.
Term
1-2%. what happens to the remaining 98-99%? leaves reflect some and molecules other than photosynthetic pigments absorb most of the remainder.
Definition
where water and nutrients do not limit plant production severely, the photosynthetic efficiency of an ecosystem as a whole varies between ___ and ___ %.
Term
25-75%
Definition
leaves and other surfaces reflect anywhere from ___ - ____% of light energy.
Term
increases
Definition
rate of photosynthesis ______ as temperature rises (up to a pt.)
Term
16 degrees C, 38 degrees C
Definition
optimum temp. for photosynthesis varies with the prevailing temperature of the environment- from about ____degrees C in many temperate species to as high as _____ degrees C in tropical species.
Term
increases, decrease
Definition
net production depends on the rate of respiration as well as on the rate of photosynthesis, and respiration generally ____ with increasing leaf temp. thus, net prod. (and therefore net assim. of CO2) may _______ with increased temp.
Term
stomates, water, transpiration
Definition
tiny openings in leaves through which CO2 and O2 are exchanged with the atmosphere, and which also allow ___ to leave the leaf by ____.
Term
close
Definition
when soil moisture approaches a plant's wilting point, stomates _____.
Term
transpiration efficiency (water use efficiency)
Definition
number of grams of dry matter produced (net production) per kilogram of water transpired
Term
2g/kg, 4g/kg
Definition
in most plants, transpiration efficiencies are < ___ g of production per kilogram of water, but they may be as high as ____ g per kilogram in drought-tolerant crops
Term
nitrogen, phosphorus
Definition
when nitrogen and phosphorus fertilizers were applied singly and in combination to chaparral habitat in southern Ca, most species responded with increased production to additions of _____ but not _____.
Term
phosphorus, nitrogen
Definition
growth of Ca lilac bushes, which harbor nitrogen-fixing bacteria in their root systems, responded to the addition of _____ but not _____.
Term
aquatic
Definition
nutrients limit primary production most strongly in ___ environments.
Term
5-20%
Definition
only ___ - ___% of energy passes between trophic levels
Term
ecological efficiency (food chain efficiency)
Definition
percentage of energy transferred from one trophic level to the next
Term
egestion
Definition
regurgitation of food components that are difficult to digest.
Term
assimilated energy
Definition
ingested energy - egested energy
Term
production
Definition
assimilated energy - respiration - excretion
Term
assimilation efficiency
Definition
ratio of assimilation to ingestion, usually expressed as a percentage. depends on food quality,
Term
lowest
Definition
the most active animals have the ____ net production efficiencies
Term
net production efficiency
Definition
ratio of energy contained in an organism's production to the total assimilated energy
Term
low, high
Definition
active, warm-blooded animals exhibit ____ net prod., sedentary, cold-blooded animals, particularly aquatic, have _____ net prod.
Term
gross production efficiency
Definition
product of assimilation efficiency and net prod. efficiency
Term
net production efficiency for plants
Definition
ratio of net production to gross production (plants)
Term
detritus
Definition
dead remains of plants and undigestible excreta of herbivores
Term
exploitation efficiency
Definition
proportion of prod. on one trophic level that is consumed by organisms on the next higher level.
Term
residence time
Definition
the longer the ______ ____, the greater the accumulation of energy
Term
residence time
Definition
(energy stored in biomass)/(net productivity)
Term
biomass accumulation ratio
Definition
(biomass)/(rate of biomassproduction)
Term
energy budget
Definition
lindeman constructed the first ____ ____, for cedar bog lake in mn.
Term
allochthonous
Definition
organic materials produced outside the system
Term
autochthonous
Definition
photosynthesis that occurs within the system
Term
autochthonous, allochthonous
Definition
in general, _____ prod. predominates in large rivers, lakes, and most marine ecosystems; ______ prod. make up the largest part of energy flux in small streams and springs under the closed canopies of forests.
Term
egested, detritus
Definition
material not assimilated is _____ and becomes part of the _____ food chain.
Term
oxygen saturation
Definition
equilibrium amount of dissolved O2 pure water can hold
Supporting users have an ad free experience!