B4g: Decay Flashcards
Factors increasing rate of decay (4)
+microorganisms, more of them to decay other living thing more quickly
+temperature (until optimum temperature reached): microbes respire faster, will grow and reproduce faster
+oxygen: microbes can use aerobic respiration to grow and reproduce faster
+water (moist conditions): allows for material to be digested and absorbed more efficiently and increase growth and reproduction
Groups of organisms involved in decay (2) + examples
detrivitrores - e.g. earthworms, maggots, millipedes, woodlice
decomposers (mostly saprophytes) - e.g. bacteria, fungi
What does detritivores do and how
increases rate of decay by increasing SA of dead remains for decomposers to act on
What is a saprophyte
an organism that feeds on dead and decaying material by extracellular digestion
How do saprophytes feed(3)
saprophytes release enzymes onto dead animal/plant
enzymes digest dead material through extracelullar digestion
saprophytes absorb digested substances
How does canning reduce the rate of decay(2)
foods are heated to kill bacteria
foods sealed in a vacuum to prevent entry of oxygen and bacteria
How does cooling reduce the rate of decay
slow down bacterial and fungal growth and reproduction
How does freezing reduce the rate of decay
kill some bacteria and fungi and slow down their growth and reproduction(or stop it)
How does drying reduce the rate of decay
removes water so decomposers cannot carry out cell reactions, grow or reproduce
How does adding salt/sugar reduce the rate of decay(2)
decreases water concentration in the food, drawing out water from the decomposers through osmosis
-without water, they cannot carry out cell reactions, grow or reproduce
How does adding vinegar reduce the rate of decay
produce very acid conditions killing most decomposers
