Studied by 1 person
What is an organism?
a single living individual
What is a population?
all the organisms of the same species in an area
What is a community?
all the populations in an area
What is an ecosystem?
all the living organisms (the community) and the non-living components in an area
What does interdependence mean?
the survival of one species is closely linked with another species
What is a parasite?
An organism that feeds on another organism (the host) while they are living together
Give examples of parasites
fleas, head lice, tapeworms, mistletoe
What is mutualism?
when two organisms live closely together in a way that benefits them both
What type of sampling is done with quadrats?
random sampling
What type of sampling is done with belt transects?
systematic sampling
Why are belt transects used?
to see how a change in a factor affects a population
How can you calculate the number of organisms in an area using data from quadrats?
divide the total area by the area of one quadrat and then multiply your answer by the mean number of organisms in one quadrat
Why would repeating the transect multiple times and comparing the results be a good idea?
it would help to average out any random variables
growing one kind of fish in an area, the fish are fed and the waste they produce is removed from the tanks
What is fish farming?
Give two disadvantages of fish farming
the waste can pollute the local area, changing conditions so that some local species die out;
diseases from the farmed fish (such as lice) can spread to wild fish and kill them
Give an advantage of fish farming
it reduces fishing of wild fish
Give two disadvantages of the introduction of non-indigenous species to an ecosystem
they may reproduce rapidly as the have no natural predators in the new area; they may out-compete native species for food or other resources
Give an advantage of the introduction of non-indigenous species to an ecosystem
they may provide food for native species
What is eutrophication?
an excess of nutrients such as phosphates and nitrates in water from fertilisers dissolving in rain water
How can eutrophication lead to a loss of biodiversity?
Plants and algae grow more quickly and block light to deeper water
deeper plants die
bacteria decompose the dying plants and take oxygen from the water;
fsh die due to lack of oxygen
Why should humans maintain local and global biodiversity?
humans should respect other organisms;
people enjoy seeing variety of organisms in different habitats;
some organisms have an important role in ecosystems;
some species are particularly useful to humans.
What is reforestation?
replanting forests where they have been destroyed
Give advantages for reforestation
restores habitat for endangered species;
reduces concentration of CO2 in the air due to photosynthesis;
tree roots bind the soil and minimise soil erosion;
reduces the range of temperature variation in the local climate
What is the role of microorganims in the carbon cycle?
decomposers
How does respiration fit into the carbon cycle?
it releases carbon dioxide into the air
How does photosynthesis fit into the carbon cycle?
it absorbs carbon dioxide from the air
How does combustion fit into the carbon cycle?
it releases carbon from fuels into the air as carbon dioxide
What is desalination?
producing drinking water from salty (sea) water
Name a process used to produce potable water in a area that is close to the sea
distillation
Draw and label the water cycle
labels: precipitation, condensation, evaporation, transpiration
What is added to fertilisers to help plants to grow better?
nitrates
What is crop rotation?
growing different crops each year on a rotation basis
How does crop rotation improve soil fertility?
different crops remove different nutrients from the soil; some plants have nitrogen fixing bacteria in their roots which can be ploughed back into the soil.
Draw and label the nitrogen cycle
labels: death and excretion, proteins and urea, nitrates, nitrogen-fixing bacteria, lightening, ammonium compounds, air, soil, plant roots
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Flashcard (100)