topic 9 - ecosystems and material cycles Flashcards
how does increasing human population affect food security levels?
increases food security
how does increased animal farming and meat and fish consumption affect food security levels?
increased consumption, less energy and less biomass every time you move up the food chain, there’s also a risk of over-fishing and there not being enough in future
how does the impact of new pests and pathogens affect food security levels?
causes damage to crops, decreases food security, wipes out large numbers of crops and reduced yield
how do environmental changes caused by human activity affect food security levels?
burning fossil fuels increases global warming and affects growth of crops which could reduce yields
how do sustainability levels affect food security levels?
increase in crops and growth to grow biofuels, take up land that could be used for crops, high input costs of farming makes crops expensive to grow
how are nitrates made available for plant uptake?
ammonia is converted to nitrates by nitrifying bacteria in the soil
what is the role of bacteria in the nitrogen cycle?
they convert atmospheric nitrogen into nitrates
what is the importance of the nitrogen cycle?
essential for the formation of amino acids, which form proteins
what is the importance of the carbon cycle?
it can affect the amount of heat contained in the atmosphere
moves carbon from the air between the ocean and the atmosphere
how is the carbon cycle involves in the role of micro organisms as decomposers?
decomposers break down the dead minerals from plants and other organisms, and release carbon dioxide into the atmosphere
what is the importance of the water cycle?
enables availability of water for all living organisms
regulated weather patterns on our planet
how is the water cycle involves in the production of potable water?
removes salt and minerals from seawater (water desalination)
how does temperature, water content and oxygen affect the rate of decomposition in food preservation?
temperature - lower temperatures decrease the rate of decomposition
water content - drying foods removes the water that micro organisms need to survive, as does adding salt or sugar - causes micro organisms to lose water by osmosis
oxygen availability - airtight storage stops micro organisms getting in, they are sealed and sterilised
which indicator species indicate:
polluted water
clean water
air quality
polluted water - bloodworm, sludgeworm
clean water - stonefly, freshwater shrimps
air quality - lichen, blackspot fungus on roses
how does the effect of water content, temperature and oxygen availability, affect the rate of decomposition in composting?
temperature - warmer temperatures speed up enzyme controlled reactions, decay happens faster, enzymes denature if temperatures are too high
water content - decays faster in moist environments as the organisms involved in decay need water
oxygen availability - rate increases when there is a large supply of oxygen, microorganisms need oxygen to respire
what are some benefits of reforestation?
provides food and shelter for lots of different species
helps restore biodiversity
if there are lots of types of trees there is higher biodiversity compare to just one type of tree
what are some benefits of the conservation of animal species?
protects natural habitats
protects species in face areas outside their natural habitats
the use of seed banks store and distribute seeds of rare and endangered plants
what are some benefits of maintaining local and global biodiversity?
protecting human food supply - over fishing has greatly reduced fish stocks in oceans
ensuring minimal damage to food chains - conserving species to help other survive
provides new jobs
ecotourism - brings money to biodiverse areas
what are some advantages and disadvantages of eutrophication?
ad - none
dis - nitrates are put into fields as fertilisers, if too much is added and then it rains, the nitrates find their way towards rivers and lakes
- causes algae to grow fast and block out the light
- plants cannot photosynthesise without light and so they die
- with more food available, organisms will increase and so will oxygen consumption
- organisms cannot then respire without oxygen and so they eventually also die
what are some positives of the introduction of non-indigenous species?
faster growth and reproduction rates
higher ecological tolerance
contributes to ecosystems stability
increases biodiversity
what are some negatives of the introduction of non-indigenous species?
causes competition for food and shelter
non-indigenous species could be stronger and so indigenous species may die out ‘
they may bring about new diseases into the habitat
what are some positives of fish farming?
fish are protected from predators
competing species cannot enter the farm
indoor farmed fish are protected from weather changes
what are some negatives of fish farming?
produce huge amounts of waste from food in nets given to the fish
food and waste can leak into open water causing eutrophication
predators get trapped and die
fish can escape into the wild causing problems to non indigenous species
how do you calculate the efficiency of energy between trophic levels?
efficiency = (energy transferred to next level / energy available at previous level) x 100
how do you calculate percentage of biomass between trophic levels?
efficiency = (biomass transferred to next level / biomass available at previous level) x 100
what is the energy transferred to at each trophic level?
less useful forms
what does the energy transferred at each trophic level affect?
number of organisms at each tropic level
limits length of food chain
determines the shape of the pyramid of biomass in an ecosystem
what are the trophic levels?
- producers
- primary consumers
- secondary consumers
- tertiary comsumers
