Distribution of organisms Flashcards
What is the name of the living factors which affect the distribution of organisms
Biotic factors
Which is the name for the non living components which affects an organism
abiotic factors
name five biotic factors
food availability
disease
predators
competition for resources
grazing
name four abiotic factors
temperature
soil moisture
light intensity
Soil ph
What is the instrument used to measure light intensity
Light metre
what is a source of error when using a light metre and how to minimise error
shadow cast on metre
avoid casting a shadow on the metre
what is the instrument used to measure temp
thermometer
what is a source of error and ways to minimise when measuring temp
damp or dirty probe
clean probe between readings
what is the instrument used to measure Ph
Ph metre
what is a source of error and ways to minimise when measuring soil ph
damp or dirty probe
clean probe between readings
what is the instrument used to measure soil moisture?
Moisture meter
what is a source of error and ways to minimise when measuring soil moisture
Damp or dirty probe
clean probe between readings
why do you repeat a test
to make the results more reliable
what is used to sample plants
Quadrats
what do you have to make sure when taking a sample when using quadrats
equal in size
chosen at random
what do you count when using quadrats
we count the number of squares the organism appears in
what is used to measure small invertebrates
pitfall traps
what is a source of error when using pitfall traps
traps not camouflaged
traps too shallow
traps aren’t covered up
why should a pitfall trap be covered
so that it is dark and so plants can’t fly out or be eaten by birds before being counted
why is it important to regularly check pitfall traps
to ensure organisms don’t escape or get eaten before being counted
why are keys used
to identify unknown organisms
name the two different types of keys
branched key
paired statement key
what human activities can cause a decrease in biodiversity
pollution - air and water
habitat destruction- deforestation
overfishing
intensive agriculture
what is intensive agriculture
aims to produce as much yeild as possible by using chemicals in order to feed the growing population
whose presence or absence indicates the level of pollution in an environment
indicator species
