Bio 20: Section 1.2 Flashcards
what is an ecosystem?
biotic & abiotic factors interacting (in time & space)
the first trophic level provides all the ____________ required to fuel the other trophic levels
energy
what is on the first trophic level? (always)
producers
which trophic level contains producers?
the first
what is on the 2nd trophic level?
herbivores, primary consumers
what is on the 3rd trophic level?
carnivores, secondary consumers
what is on the 4th trophic level?
carnivores, tertiary consumers
why are food chains not likely to go beyond 4-6 trophic levels?
b/c the 2nd law of thermodynamics states that energy is lost in other forms
so, as energy is transferred several times b/w trophic levels, more and more energy is lost
a simple model that shows the linear pathways through which energy is transferred from producer to top carnivore up the trophic levels
food chain
a model of energy transfer in an ecosystem that shows the connections among food chains
food web
what % of energy is transferred from one trophic level to another?
10%
what are two ways that energy is lost to the environment?
passing of indigestible matter that decomposers break down (creates heat)
generation of heat through biological processes
what does cellular respiration do when it comes to consuming food?
it breaks down the energy content in the food so that it can be used by the organism that’s consuming it
why is less energy transferred form one trophic level to another?
2nd law of thermodynamics states that systems are not 100% efficient and energy will be lost as it is transferred from one level to another
where are decomposers on the trophic chain?
any trophic level, but the first, b/c they can’t be producers
why can’t decomposers be producers?
b/c they get their energy from breaking down the contents of dead organisms and recieve their food from there, while producers get their energy from the Sun or chemicals (ex. hydrogen sulfide)
and also, decomposers are consumers
if a worm species on the 2nd trophic level decreases, what happens to the small birds on the 3rd trophic level?
the birds will starve and decrease in population
a moose consumes 3500 kJ of energy from a balsam fir tree. Estimate how much of this energy would be available to a wolf that consumes the moose.
350 kJ
what are the 3 types of ecological pyramids?
numbers
biomass
energy
compares population number between trophic levels
represents the relative number of organisms at each link (or each trophic level) in a food chain
pyramid of numbers
in many ecosystems, organisms at higher trophic levels are ___________ in number than organisms at lower trophic levels
lesser
where organisms at a lower trophic level are lesser in number than organisms at a higher trophic level
inverted pyramid of numbers
in some ecosystems, a smaller number of ___________ organisms at a lower trophic level can support a larger number of smaller organisms at higher trophic levels
large
is a large tree is at the lowest trophic level, can its biomass be more than that of insects at high trophic levels?
yes
the relative dry mass in grams per square meter of living or once living organisms in an ecosystem
biomass
there is less biomass at the first trophic level than at the second trophic level
inverted pyramid of biomass
shows the transfer of energy from one trophic level to the next
pyramid of energy
while the estimate for energy loss is 10%, what is the range for the actual effiecieny?
5% to 20%
in all ecosystems, there is _______ energy at the higher trophic levels than at lower trophic levels
less
true or false: there are inverted pyramids of energy
false: there can never be less energy in a lower trophic level than in a higher one
if there was such thing as an inverted pyramid of energy, which law would that be breaking?
the 1st law of thermodynamics
