B4.12/13 - Decay & Preventing Decay Flashcards
What happens when dead plants or animals decay?
Their bodies decay and this decay process releases the elements back into the environment for the plants to reuse, continuing the elements cycle.
In what way is the elements cycle a way of natural recycling?
Nature breaks down the remains of plants and animals to return the elements, so they can be used again.
What are the two main groups of microbes involved in decay?
Bacteria & Fungi
What is compost?
Compost is used as a natural recycling process. Gardeners gather their waste grass cuttings, leaves and twigs and put them in a compost bin to decay. This decay causes a nutrient rich soil which can be used to grow plants in.
In what conditions would decay happen faster? Name 3
- When it is warmer
- When it is moist
- When there is more oxygen
Why does decay happen faster in warmer conditions?
Microbes are able to respire faster and will grow and reproduce quicker in warmer conditions.
Why does decay happen faster when there is more oxygen present?
The more oxygen there is available, the faster the microbes will be able to respire. This will allow them to grow quicker and reproduce faster.
Why is decay faster in moist conditions?
Microbes and water to remain healthy. In moist conditions the microbes will grow faster and reproduce more.
What is detritus?
Dead plants/animals and animal waste
What are the two main groups of decay organisms?
Detritivores & Decomposers
Give two examples of detritivores and what they do
- Millipedes and earthworms are detritivores.
- Detritivores eat small parts of dead material, which they digest and then release as waste. This activity increases the surface area of the dead remind for decomposers to act on.
Give two examples of decomposers and what they do
- Bacteria and fungi are decomposers.
- Decomposers chemically break down dead material, releasing ammonium compounds into the soil.
What is saprotrophic feeding?
Most decomposers are an example of saprotrophic feeders. Saprotrophic feeding is when organisms feed by releasing enzymes onto the dead animal or plant. The enzymes digest the dead material in a process called extracellular digestion. The organisms then absorb the digested chemicals.
Why do we need to keep food fresh?
If we do not it will decay and we cannot safely eat decayed food.
Name four impacts of decay on food
- Reduces the amount of food there is for people to eat.
- In areas of food shortage, decay of foods can cause malnutrition.
- Eating food that is decaying can lead to illness.
- The profits of farmers and supermarkets is reduced if food decays before it is sold.
