b7 Flashcards
give three environmental factors that affect plant growth.
- light intensity
- soil ph
- water or moisture
to investigate decay of milk, how does the student keep milk at a constant temperature?
place in water bath
when investigating decay of milk, what product makes ph decrease?
lipids break down into fatty acids
why would different types of milk have different rates of decay?
- different concentration or type of lipid
- different concentration or type or sugar
- different type of bacteria present
what two types of organisms cause decay?
- bacteria
- fungi
give three environmental factors needed for decay
- oxygen
- water
- temperature
what is the main gas found in biogas?
methane
why would a farmer spread dead plant material onto his fields?
used as fertiliser as it contains mineral ions so plants grow faster
why is a large surface area to ratio volume an advantage to respiring organisms?
can absorb more oxygen in a given time
why is it advantageous to place quadrats at random positions when sampling fields?
- to avoid bias
- more representative
- there is an uneven distribution of dandelions
when investigating decaying milk, why should you sterilise the flask before adding milk?
to kill bacteria in flask so only microorganisms in the milk cause the results
how could students sterilise a flask in a school lab?
heating to over 100°C
when investigating decay of milk, why is there a lid on the top of the flask?
to prevent microorganisms entering from the air
what’s the advantage of using a pH meter instead of universal indicator paper?
more accurate and precise
during the first few days of decay, why is rate of decay low?
too few bacteria
when sampling a field, what is tape measure used for?
to measure the area of field
why might a farmer be against using anaerobic decay in a compost bin?
- produces methane
- which is a greenhouse gas so causes global warming
what is meant by biodiversity?
the variety of all the different species of organisms on earth or in an ecosystem
give two uses of peat taken from peat bogs
- compost / fertiliser
- burned as fuel
why is the use of peat harmful to the environment?
decay/ burning of peat releases carbon dioxide which is increasing global warmint
why is the use of antibiotics in farming a threat to human life?
- antibiotics in animal faeces flows into rivers
- bacteria in water become antibiotic resistant
- sone of these bacteria are human pathogens
- so human diseases can not be cured as they are antibiotic resistant
give three reasons why deforestation occurs.
to clear land for…
- mining
- to raise cattle (agriculture)
- building
- paper
what is the order of living things?
- organism
- population
- community
- ecosystem
what do animals compete for?
- food
- territory
- mates
