Ecology-decay

How does the number of decay organisms affect the rate of decay?

The more microorganisms and detritus feeders there are the faster decomposition happens

How does water availability/amount affect the rate of decay?

Decay takes place faster in moist environments bc the organisms involved in decay need water to carry out biological processes

How does temperature affect the rate of decay?

Decomposition takes place more faster in warmer conditions as decomposers use enzymes to break down plant materials and these enzymes work faster in warmer conditions

What happens if the temperature is too hot /cold in decay?

Enzymes in decomposers can denature and decomposers can die causing decomposition to slow down or stop

When too cold it slows down the rate of decomposition

How does the amount/availability of oxygen affect the rate of decay?

Decomposers carry out aerobic respiration which requires a good supply of oxygen

What factors affect the rate of decay?

Temperature, oxygen/water availability, number of decay organisms

Why do compost bins tend to already be warm?

Bc Decomposers release energy when they carry out aerobic respiration

What does decomposing microorganisms carry out in a compost heap?

Aerobic respiration

What happens to decomposing microorganisms if there isn’t oxygen?

They carry out anaerobic decay

What does anaerobic decay produce?

A mixture of gases including methane /carbon dioxide this is known as biogas

What is compost?

decomposed organic matter that is used as a natural fertiliser for crops and garden plants

What does it do/ what is it used for?

It recycles nutrients back into soil. Compost bins recreate the ideal conditions for decay

What are the products of decay?

Carbon dioxide- from respiration

Methane-during anaerobic decay(e.g. biogas

Nutrients-returned back to soil

What does compost need?

Oxygen,moisture and water

What is the best condition for decay to occur?

Moisture, oxygen and warmth

Explain fully the practical that investigates the rate of decay?

1) measure out 5cm3 of lipase solution and add it to a test tube

2) measure out 5cm3 of milk and add it to a different test tube

3)add 5 drops of phenolphthalein indicator to the tube containing milk

4) then measure out 7cm3 of sodium carbonate solution and add it to the tube containing milk and phenolphthalein.this makes the solution in the tube alkaline so it should turn pink

5)put both tubes into a water bath set to 30degreesC and leave them to reach the temp of water bath

6) once tubes have reached 30dC use pipette to put 1cm3 of lipase solution into milk and start stopwatch straight away

7) stir contents of tube with a glass rod the enzymes will start to decompose the milk

8) as soon as solution loses its pink colour stop the stopwatch and record how long colour change took in table

9)repeat with diff temperatures

What is the practical investigating?

The effect of temperature in the decay of milk by lipase

What are the variables in practical?

Independent-temperature

Dependent- time taken for indicator(phenolphthalein)to change colour

Control-volume of milk/volume and concentration of lipase enzyme

How do u calculate the rate of decay?

Rate=1000/time

What is biogas mainly made up of?

Methane

What are used to produce biogas and what do they decay?

Lots of different microorganisms are used they decay plant material and animal waste anaerobically(without oxygen) this type of decay produces methane gas

What is biogas made in?

A simple fermenter called a digester or generator

Why do biogas generators need to be kept at constant temp?

To keep microorganisms respiring away

What are the types of biogas generators and what do they do?

Batch generators- make biogas in small batches they don’t need to be filled up as often as continuos generators but don’t produce biogas at a steady rate

Continuous generators-make biogas all the time biogas produced at a steady rate CG are more suited to large scale biogas projects