Chapter 4: Energy and Matter in Ecosystems Flashcards
what is a biogeochemical cycle
the cycling of matter through the abiotic factors such as rocks and atmosphere and biotic factors such as plants and animals
what is the geochemical cycle
matter cycled through the lithosphere through chemical reactions in the earths crust
what is a chemotrophic organism
organism that are autotrophic that live below the zone where light can penetrate
what is biomass
the total amount of dead or alive biological matter in a given area at a given time.
measured g/m^2
what is primary productivity
the amount of energy turned into biomass by producers
what is photosynthetic efficiency
how well a producer turns light energy into carbs
factored by temperature, season and altitude
what is primary productivity measured in
kj/m^2 year^1
what role do herbivores serve
they are able to break down cellulose
what is detritus
dead animal or plant matter
when would an inverted pyramid of numbers occur
when a parasite feeds on the apex predator
when would a pyramid of biomass be inverted
when an efficient producer such as phytoplankton has a short life cycle but produces a lot of energy for it’s size.
key phrases of carbon cycle
moving through reservoirs rapidly
most abundant element in living things
circulate through biotic and abiotic
carbon cycle
mainly carbon dioxide gas
why are nitrogen fixing symbiotic relationships important
no free nitrogen particles in the soil
all of it is fixed into an organism
doesn’t get eroded away
extra nitrogen can kill earthworms and cause algal blooms when soil erosion carries it away
what are nitrogen-fixing bacteria symbiotic with legumes called
azotobacter
define ecological niche
an organisms function in an environment - the time they feed, what they feed on, habitat etc
explain fundamental vs realised niche
the fundamental niche is the niche a species would fill if there was no outside competition - theoretical
the realised niche is narrower and is more practical as this accounts for competition from outside species
such as an ideal situation for a bilby is they would be able to be diurnal and nocturnal but due to excess competition during the day it has adapted to the realised niche
explain what resource partitioning is
resource partitioning is when multiple species adapt to exploit different niches of an area to reduce competition
e.g birds adapt different beak shapes and sizes to exploit different areas of the tree
what is the competitive exclusion principle
multiple species cannot fill the same niche for an extended period of time
one species will out compete the other
explain what a keystone species is
little abundance compared to the effect they have on the ecosystem
seed dispersal, predation, nutrient cycling
what is the role of decomposers
they break down complex organic materials into simple inorganic nutrients so that they can reenter the foodchain via producers
explain what nitrifiers, denitrifiers and nitrogen fixers are
nitrifiers turn organic waste like faeces into nitrites
denitrifiers turn nitrates in the soil into nitrogen gas
nitrogen fixers turn atmospheric nitrogen into nitrates and nitrites
