topic 9 ecosystems Flashcards
levels of organisation
individual - single organism
population - all the organisms of one species in a habitat
community - all organisms of a different species living in a havitsf
ecosystem - a community of organisms along with the non living (abiotic) conditions
interdependence definition
organisms depend on each other
what is mutualism
a relationship between two organisms from which both organisms benefit
what is a parasite
live very closely with a host
takes what it needs to survive but the host doesn’t benefit
e.g fleas feed on the host blood but doesn’t offer anything in return
abiotic factors
temperature
water availability
light intensity
levels of pollutants
biotic factors
competition
predation
disease
core practical - distribution
place a 1m^2 quadrant on the ground at a random point
count al organisms you’re interested in within the quadrant
repeat lots of times steps 1 and 2
find mean by divide total number of organisms by number of quadrants
repeat whole process again
compare the two means
belt transect core practical
mark a line in the area u wanna study
collect data along the line using quadrants placed next to each other
repeat steps 1 and 2 then find mean number for each quadrant
what is eutrophication
fertilisers enter water adding excess nitrates
excess nitrates cause algae to grow fast and block out the light
plants can’t photosynthesise due to lack of light and begin to die and decompose
decomposers feed on the plants and use up the oxygen
organisms like fish that need oxygen for aerobic respiration die
fish farming advantages
preserves the wild population
selectively breed to ensure high quality fish
control water quality
fish farming disadvantages
disease spreads easier
fish excrete waste a lot and that goes into the ecosystem spreading bacteria
introducing non native species advantage
pest control
introducing non native species disadvantage
no natural predators so population booms as they can outcompete
biological levels affecting food security
increase in consumption of meat and fish which increases animal farming (overfishing, people get rich and want more meat and fish, takes longer than growing crops)
environmental changes caused by human activity (burning fossil fuels, climate change, soil pollution)
sustainability
new pests and pathogens
carbon cycle
green plants use carbon from co2 to make fats and proteins
eating passes the carbon compounds in plants to animals in a food chain
both animal and plants respiration
release co2 back out into air
they eventually die and decompose
microorganisms break down the material and release co2
useful plant and animal products are burned and releases co2 in the air
water cycle
energy from the sun makes water evaporate and it turns into water vapour
water also evaporates from plants (transpiration)
warm water vapour carried upwards
cooks and condenses to form clouds
water falls from clouds as precipitation
drains into sea
nitrogen cycle
nitrogen in the air turns into nitrates
plants absorb the mineral ions from the soil and use the nitrogen in them to make proteins
nitrogen is passed along the food chain
decomposers break down proteins in rotting plants and animals which returns nitrogen to the soil
nitrifying bacteria definition
turn ammonia in decaying matter into nitrites and then nitrates
nitrogen fixing bacteria
turns nitrogen gas into ammonia which forms ammonium ions
denitrifying bacteria
turns nitrates back into nitrogen gas
often found in waterlogged soils
nitrogen fixing bacteria on nodules
some live in nodules on the roots of legume plants
when the plants decompose, nitrogen stored in their nodules is returned to the soil
they can also leak out of nodules during plant growth
it is a mutualistic relationship with the bacteria as they get food from the plant and the plant gets nitrates to make into proteins
crop rotation
different crops are grown each year on a cycle
usually includes a nitrogen fixing crop (peas or beans) to put nitrates back into the soil for another crop to use a following year
fertilisers
animal manure or compost return nutrients left in a plant through decomposition
artificial fertilisers containing nitrates can also be used
indicator species (water)
clean - stonefly larvae
polluted - bloodworms and sludge worms
