ecosystems/ecology Flashcards
definition of habitat
the place where an organism lives
definition of community
all the different species in a habitat
definition of population
all the organisms of one species in a habitat
eg the human population
definition of ecosystem
all the organisms living in a particular area and all of the non-living conditions eg temperature, climate, soil type
word meaning ‘non-living’
abiotic
(think A- prefix meaning non- eg Asexual,
word meaning ‘living’
biotic
what are some abiotic conditions?
NON-LIVING
- toxic chemicals eg fertilisers or pesticides)
- environmental conditions eg soil pH, light intensity, moisture levels, temperature average
what are some biotic conditions?
LIVING
- availability of food
- number of predators
- competitions between organisms
changes in the environment are caused by a…… and b……. factors
- abiotic
- biotic
food chain list:
- producers
- primary consumers
- secondary consumers
what are each stage of a food chain called?
a trophic level
what is transferred along a food chain?
ENERGY
sun —-> everything else
why does most energy not get transferred?
- not all of the organism is eatable
- some parts are not digestible so are lost as faeces
- some are used in life processes eg respiration
- lost as heat/transferred to surroundings
what is a quadrat (practical)
a quadrat is a square frame enclosing a known area
(to find the population of a species)
mean number of organisms per quadrat equation
mean = total number of organisms/number of quadrats
then to work out population multiply the mean by the total area of the habitat
what are belt transects used for?
they are used to find out how organisms are distributed across a habitat
what is a pyramid of number
it shows the numbers of each trophic level eg 500 dandelions feeds 100 rabbits which feed 1 fox
(not always in a pyramid shape)
what is a pyramid of biomass
this shows the distribution of WEIGHT eg one fox would have a very large biomass but 500 fleas would have much lower
(usually in a pyramid shape)
pyramids of energy show
the exchange in energy
- always in a pyramid shape because only 10 percent of energy transfers
species in a food web are i……..
interdependent
which means if one species changes, it impacts all the rest
what is a food web?
it shows how different food chains are linked
eg if grass –> rabbit —-> fox
if grass —-> cow —–> human
if lots of foxes die, more rabbits survive so more grass is eaten. therefore cows have less food so may die, so humans eat less.
Food webs show other factors that impact food chains, even if they’re not directly part of that chain.
