Energy Flow Through Ecosystems Flashcards
How much of the fresh water on earth is due to ground water?
95%
What is percolation?
movement of water through layers of soil (to collect into ground water)
What is fracking?
digging through the earth’s surface in order to get gas
Why is fracking harmful?
it can contaminate ground water
Is percolation a fast or slow process?
slow process
When is water produced and consumed?
water is produced during cellular respiration and consumed during photosynthesis
What does fixation mean?
turning (unusable) gas molecules to an usable form (organic)
What is the main source of carbon for all organisms?
CO2
What organism fixes CO2 into it’s usable form?
plants (through photosynthesis)
Who breaks down the organic form of carbon back into CO2?
plants and animals (through cellular respiration)
How else does organic carbon end up back as CO2 in the environment?
methanogens and decomposition
What is methanogens?
bacteria that release methane gas as a byproduct of various reactions
Is the carbon cycle stable or unstable?
stable
What is one thing that has disrupted the carbon cycle?
burning of fossil fuels b/c during the carboniferous period, dead plants would be compacted into the soil and since the plants were’t burned, there was no excess release of CO2, but now with the burning of fossil fuels, theres an excess of CO2 causing problems
How much of the atmosphere is made up of nitrogen?
78%
Can a lot of organisms convert N2 to NH3?
nope, only a few
What are examples of organisms that can fix nitrogen?
cyanobacteria, rhizobia in legumes
What else can fix nitrogen?
lightening or other high energy source
What exactly is nitrogen fixation?
converting H2 to NH3 or NO3-
How and in what form do plants get nitrogen?
they get nitrogen from the soil in the form of NH3 or NO3-
How do animals get nitrogen?
from plants
What do animals use nitrogen for?
buildup of proteins and nucleic acids
How does nitrogen come out of animals?
via excretion or decomposition
What is denitrification?
when anaerobic bacteria turn nitrate back to nitrogen gas
What is special about phosphorus?
it does not have a gaseous phase
How do animals and plants get phosphorus?
phosphorus weathers from rocks and plants take it up in soil, and animals eat the plants
How do animals release phosphorus?
via excretion or decomposition
What is a downside of phosphorus?
it needs to be taken up by plants from the soil quickly, or it can get washed away and lead to eutrophication
What is a source of iron for phytoplankton?
saharan dust blowing across the Atlantic
Where does all energy come from?
the sun
How much of the suns energy do we actually use?
1%
What are trophic levels?
a food web that shows the transfer of energy
What is net primary productivity?
the amount of biomass or carbon produced by primary producers
What is the equation for net primary equation?
GPP (energy made during photosynthesis)-R (energy used by the producer for its own processes)
What is secondary productivity?
food eaten (energy consumed to grow and develop) - energy lost (through feces or cellular respiration)
About how much energy is transferred from one trophic level to the next?
10%
What is the pyramid of energy?
depicts the energy at each trophic level
Why is the pyramid of energy always upright?
because energy always flows from producers to consumers (unidirectional), and an environment without sufficient primary productivity will die off
What is the pyramid of biomass?
represents the mass of organisms at each trophic level
Why can the pyramid of biomass be upright or inverted?
because in ecosystems such as the ocean, fishes have higher biomass than primary producers (because they are tiny and die off very quickly)
What is the pyramid of individuals?
shows the distribution of age and sex of a population or how much of producers, carnivores are in an population
What is the top-down effect?
alterations in upper tropic levels impact lower trophic levels
What is the bottom up effect?
alterations in low trophic levels impact higher trophic levels
What dies island biogeography graph show?
the number of species on island equilibrium between extinction and colonization
What is the impact of distance on colonization?
far: less colonization
near: more colonization
What is the impact of a bigger island on extinction?
big: less extinction (less comp and more species)
small: more extinction
