ecosystems and material cycles Flashcards
what is an ecosystem
a community of organisms with all abiotic conditions in an area
what is a community
all the organisms of different species living in a habitat
population
all the organisms of one species in a habitat
how is a belt transect used?
it shows the distribution of organisms along a gradient
what is eutrophication
this is when fertilizers leach into water. this causes an excess of nutrients in the water which can lead to the death of many of the species present in the water. the excess nutrients cause algae to grow, blocking light
how can fish farms reduce biodiversity
-food is added to the nets to feed the fish, which produce huge amounts of waste. this can leak into open water and cause eutrophication
-they also contain lots of parasites. if they get out, it will kill wild animals
what are some conservation schemes to protect at risk species
-protecting a species natural habitat
-protecting the species in safe areas outside their habitat. eg zoos
what benefits does maintaining biodiversity have
providing future medicines
-ecotourism
-can provide new jobs
what is food security
this is the ability for humans to access sufficient food
what are some factors that can affect food security
-increasing consumption of meat and fish
-sustainability-future generations may not have enough food because of how much we are eating today
what is desalination
this removes salts from salt water.
what is thermal desalination
salt water is heated until the water evaporates. this water is then collected.
what is nitrogen fixation
this is the process of turning N2 from the air into nitrogen containing ions
what are nitrogen fixing bacteria
they turn nitrogen into ammonia that plants use
where are nitrogen fixing bacteria found
root nodules
what are decomposers
they decompose proteins and urea into ammonia
what are nitrifying bacteria
they turn ammonia in decaying matter into nitrites
denitrifying bacteria
turns nitrates into N2 gas
how does the method of crop rotation increase the crop growth in soil
-there will be more nitrates in the soil which act as fertilisers for the plant
what is crop rotation
this is when crops are moved to different soils once they are grown. in this cycle, a legume plant will be involved
-after the legume plant is moved, the soil that the legume plant was in has lots of nitrates which the new plant can use as fertilisers
why is excess fertilisers bad in rivers
it can increase amount of algae and which use up oxygen
why are stonefly larvae and freshwater shirimps good indicators of water pollution
as they are very sensitive to the concentration of dissolved oxygen. if there are any of these in a river, it means it is clean
is the water dirty or clean if you see blood worms and sludge worms in the water
dirty as these animals are adapted to live in polluted conditions
what does it mean if there is lots of lichen growing
this means that the air is really clean. this is because they are sensitive to sulfur dioxide in the atmosphere, so they dont grow where there is lots of sulfur dioxide
what will the presence of blackspot fungus indicate
it means air is clean as it wont grow in high levels of sulfur dioxide
what three things does the rate of decay depend on?
-temperature
-water content
-oxygen availability
