Chapter 20: Movement of Energy in Ecosystems Flashcards
terrestrial biomes depend on
temperature and precipitation levels
aquatic biomes depend on
salinity, depth, water flow
primary producers (autotrophs)
convert energy from sun –> chemical bond energy by photo/chemosynthesis
primary consumers
herbivores
secondary consumers
carnivores eat herbivores
tertiary consumers
carnivores eat carnivores
decomposers
live on dead/decaying matter
- keystone species
biomass
energy to build body size
amount of growth and reproduction depend on…
energy available
primary productivity
rate at which solar/chemical energy is captured and converted into chemical bonds by photo/chemosynthesis
- energy available in an ecosystem
- powers all trophic levels
standing crop
biomass of producers present in ecosystem at given place/time
gross primary productivity (GPP)
rate at which energy is captured and assimilated by producers in given area in Joules/meter^2/year
net primary productivity (NPP)
rate energy is assimilated by producers and converted into producer biomass in area; how much energy the organism has (how much will a consumer get if they eat it; biomass)
- amnt energy available to consumers
NPP =
GPP - respiration;
- change in producer biomass over time
__% of solar energy is absorbed for primary productivity
40
Egested energy
portion of energy consumed that is excreted/regurgitated
Assimilated energy
portion of energy that consumer digests/absorbs
- = GPP for producers
Respired energy
energy assimilated by consumer for respiration
- net secondary productivity
Net secondary productivity
rate of energy used for biomass accumulation
- = NPP for producers
Trophic pyramid
distribution of energy/biomass among trophic groups in ecosystem
Trophic groups
position on food chain
Pyramid of energy
trophic pyramid displays total energy existing at each trophic level
Pyramid of biomass
trophic pyramid represents standing crop of organisms present in diff trophic groups
Consumption efficiency
% energy/biomass at trophic level consumed by next higher trophic level
Assimilation efficiency
% consumed energy that is assimilated
Net production efficiency
% assimilated energy used for growth/reproduction; % assimilated remaining after respiration
Ecological efficiency (food chain efficiency)
% net production from 1 trophic level compared to lower trophic level
where is energy lost?
o Not all energy is obtained from photosynthesis
o Energy loss of respiration (homeostasis)
o Energy loss of excretion
o Some parts are inedible
Energy residence time
length of time energy remains at trophic level
Energy residence time equation
Energy residence time (years) = (energy present in trophic level (J/ m2))/ (net productivity (J/m2/year)
Biomass residence time
- length of time biomass remains at trophic level
biomass residence time equation
Biomass residence time (years) = (biomass present in a trophic level (kg/ m2))/(net productivity (kg/ m2/year)
Ecological stoichiometry
balance of nutrients in ecological interactions
ecosystem
biotic, abiotic, and nonliving material
4 components of an ecosystem (that energy flow links)
abiotic environment, producers, consumers, decomposers
GPP =
NPP + respiration
abiotic environment includes
soil, climate, atmosphere, particulate matter, solutes in water
When a leaf is exposed to light, __ and __ occur; the net uptake of __ represents NPP
photosynthesis and respiration;
- CO2
when a leaf is concealed in the dark, only ___ occurs.
CO2 respiration
Remote sensing
a technique that allows measurement of conditions on Earth from a distant location, typically using satellites or airplanes that take photographs of large areas of the globe.
Satellite images that show a pattern of ____ absorption of blue and red light, and ___ reflectance of green light indicate ecosystems with high standing crops.
high, high
ecosystem ecology includes:
- how energy flows among the components of an ecosystem
- how carbon, nitrogen, and other elements cycle through organisms, sediments, oceans, and the atmosphere
- how humans affect the abiotic environment.
2-7 trophic structure are described by
food webs / food chain
how do you measure biomass?
dehydrate; the dry mass
Increases in NPP are _____ correlated with increases in net secondary productivity.
positively
where is the most secondary production?
where the most plants/primary production are
primary production in terrestrial environments
expect for deserts, terrestrial productivity declines from the equator –> poles
highest primary productivity in terrestrial environments and why?
tropical rainforests bc of….
- intense sunlight
- warm temps
- high precipitation
- rapidly recycled nutrients
primary productivity in aquatic environments (highest and lowest locations)
highest productivity in coastal waters and lowest in the open ocean
highest primary productivity in aquatic environments
swamps and marshes
lowest primary productivity in terrestrial environments
deserts (low precipitation) and arctic regions (low temps)
terrestrial net primary production is limited by…
- temperature (and sunlight)
- precipitation
mean annual precipitation is positively related w/ NPP until ___ of annual precipitation is reached
3 m
Ecosystems that receive more than 3 m of precipitation experience…
a decline in NPP because nutrients leach from the soil
Nutrients such as __ and __ strongly affect NPP in terrestrial ecosystems.
nitrogen and phosphorus
- reduces rates of decomposition
Grasslands, forests, and tundra habitats all experienced ____ NPP when nitrogen and phosphorus were added.
increased
the overall productivity of marine ecosystems is limited by the availability of ____ and ____.
nutrients and light
limiting nutrients in the ocean
silicon (for silicate shells) and iron because it attaches to P and precipitates to the bottom
on avg how much energy is lost between each trophic level? how much transferred?
~90% lost
- 10% transfered
aquatic ecosystems have __ trophic levels compared to terrestrial ecosystems because of ____.
- more trophic levels (5) than terrestrial ecosystems (3-4)
- bc of… differences in ecological efficiencies
avg. number of links in food chain
~ 3.5
higher trophic level =
higher ecological efficiency
aquatic environments have ___ energy moving up trophic levels compared to terrestrial because…
more energy bc of easy consumption (small producers) and less defense systems
where is energy lost at each trophic level?
respiration and maintenance activity
aquatic ecosystems trophic pyramids are…
inverted (upside down)
net production efficiency is much higher in ___ than ___.
poikilotherms (~75%) than homeotherms (~1%)
the longer the residence time, the ___ the accumulation of energy in that trophic level.
greater
dead organic matter residence time depends on
- decomposition rate
- temps
- precipitation
- high temps/precipitation = quicker
