ecosystems - biomass - carbon/ nitrogen stores Flashcards
ecosystem
living and non-living parts of an environment and the interactionx that occur between them
eg african savannah, tropical rainforest, garden pond, farm
biotic
living organisms
eg fish, flower, plant
abiotic
non-living
eg rock, water, table, soil
population
total no. one species in an ecosystem
eg pop of humans - 7.8bill, pop of fish - 3.5 trill
community
all plants/ animals living in a single ecosystem
individual
a single organism
biodiversity
range of diff. species in an ecosystem
habitat
place where an organism lives in an ecosystem
interdependence
where organisms depend on each other for survival
effect of temp on rabbit populations
temp increase > snow melts > white rabbits no longer camoflagued > easier for predator to spot > white rabbits more likely to be eaten > if snow disappears white rabbits could become extinct > brown rabbits less competition > pop. could explode
CO2 (plants)
0.04% in air
rate of photosynthesis increases if CO2 increases
used for photosynthesis to make food which is used for energy/growth
temp (plants)
temp increases = faster metabolic reactions - enzymes work faster and catalyse reactions more
ectotherms - rely on sun/temp to warm them and temp increases metabolic reactions
endotherms - less affected by change in temp
moisture levels (plants + humans)
10-20% of water loss is life threatening to huamns
plants lacking water - wilts - cells become plasmolysed - plant cant keep upright
plants filled with water - turgid - stays upright
soil pH (plants)
impact of soil pH changes - affects biological activity + availability of minerals
acidic soil - ferns
alkali soil - cucumber
ph of soild in high rainfall areas - acidic (alkaline compounds drain away)
as soil pH increases - elements increase - Ca, Mg, N, S, K
light intensity decrease - effect on ecosystem
plants use photosynthesis to make food which needs light
they wont be able to grow if LI is low + will die
less plants means less food for herbivores and therefore less food for carnivores so organisms cant grow or make energy so die
food chain
diagram that shows what an organism eats arrow direction (transfer of energy) TROPHIC LEVELS - each step in a food change
how glucose stores energy
in chemical bonds
apex predators
carnivore with no predators
food web
series of interlinked food chains
producer
make their own food (using sunlight) - first level of all food chains
algae, plants
primary consumer
organisms that eat producers ( herbivores)
deer, turtles
secondary consumer
eat primary consumers
pyramid of numbers
shiws the pop. at each trophi level
bar width = no. organisms
do not take into acount size of orgnisms
pyramid of biomass
amount of biomass at each trophic level
both NUMBER and SIZE of organisms present
bar = relative mass of living material
biomass calc
average mass of organisms x no. organisms = total biomass of one trophic level
challenges of measuring total biomass
- organisms need to be collected + killed to measure biomass
- difficult to catch + weight organisms
- biomass varies ( tree increases in summer , tree decreases in winter)
- some organisms feed on more than one tropic level
why is dry mass used
water content can vary between individual but dry mass cant
why is biomass lost in a food chain
- used to make energy (respiration) - lost to environment as CO2+ H2O
- lost in keeping warm (respiration)
- organism is left uneaten
- biomass is indigestible + passes out organism as faeces
loss of biomass means pyramids are limited to max 4/5 tropic levels
biomass transfer efficiency
= energy used to grow tissues/ energy eaten x 100
predator / prey relationship
follow cyclical pattern
predators dependant on prey
cycle of predator is out of phase ( lags behind) cycle of prey
mutualism
both organisms benefit from relationship
parasitism
parasites live at the expense of the host organism - harm the host
why do organisms compete
- for resources they both need
- to get sufficient resources
plants compete for
- light
- water
- space
- minerals
- pollinators
animals compete for
- mates
- teritory
- shelter
- food/water
inter specific
between diff. species
intra specific
within species
intra specific is more significant
- have same niche - compete for EXACT same resources
- can avoid other species competition cant avoid same species
decay
break down organic matter to release nutrients
saphrophytes
feed on dead matter and break it down
- releases enzymes which digest organic matter - bacteria/fungi absorb products of enzyme digestion
detrivores
speed up decay (increase surface area)
worms , woodlice, maggots
factors that speed decomposition
- water - lack of water prevents decay
- oxygen - lack of oxygen prevents decay
- temp - high temp stops decay - low temp slows decay
water cycle
evaporation
condensation
precipitation - when clouds are full water falls to ground
runoff/ percolation / transpiration - loss of water from plants
roles of water
- maintains habitat
- maintains internal fluids/ transport system
- needed for chemical reaction
- reactant in photosynthesis
nutrients cycled
carbon, water, nitrogen, oxygen
nitrogen cycle
N2 (g) > (nitrogen fixation) > ammonium > (nitrification)> nitrite> (nitrification)> nitrate >(denitrification >N2 (g)) > absorb/assimilate > N2 in plants/animals > decay > ammonia
nitrogen fixation
process of turning nitrogen in air into ammonium ions
- nitrogen fixing bacteria in soil/root nodules of legumes
- energy from lightning splits N2gas allowing it to react with oxygen and form nitrates
- haber process- artificial nitrogen fixation process
anaerobic conditions
decomposition
decomposers break down protein and urea and turn them into ammonia
nitrification
process of turning ammonium ions into nitrates
nitrification is performed by nitrifying bacteria
aerobic conditions
denitrification
turning nitrates into nitrogen gas
anaerobic conditions
by denitrifying bacteria ( IN WATER LOGGES SOIL)
carbon cycle
see diagrams of both carbon and nitrogen
the amount of C on earth is fixed
process by which carbon is cycled through the atmosphere earth plamts and animals
carbon stores
shells of marine organisms on sea ed
these compress to form limestone
acid rain (= carbonic acid from CO2 reacting with rain) weathers limestone and releases carbon
CO2 can be absorbed by oceans (carbon sinks)
volcanic eruptions and forest fires release CO2
