B4.1.8 Decomposers

Question 1

Decomposers

Answer 1

Microorganisms that break down organic molecules

Question 2

Detritivores

Answer 2

Small animals that speed up decomposition by shredding organic material into very small pieces
This creates a larger surface area for decomposers to work on

Question 3

Examples of detritivores

Answer 3

Earthworm-leaves
Woodlousse-wood
Maggot-animal material

Question 4

How do decomposers release nutrients

Answer 4

A fungus releases enzymes on to the dead remains
Enzymes digest the dead matter and make it soluble
The soluble products are absorbed by the fungus
May be used for growth and as an energy store

Question 5

Factors affecting rate of decomposition

Answer 5

Warm temperatures
Moist environments
Aerobic conditions

Question 6

Rate of decay of biological material

Answer 6

Change in mass (g)/time (day)

Question 7

How do warm temperatures affect rate of decomposition

Answer 7

At high temps the enzymes are denatured
This prevents decomposition and often results in organisms death
At low temperatures the rate of decomposition is slow as the rates of enzyme controlled reactions are reduced
The rate of microorganism replication is also slow

Question 8

How do moist environments affect rate of decomposition

Answer 8

If not enough water is available, reactions within the microorganism will slow down or be prevented
This reduces or stops the process of decomposition

Question 9

How do aerobic conditions affect the rate of decomposition

Answer 9

Oxygen is needed for the microorganisms to respire
Anaerobic conditions will prevent most forms of decomposition as the microorganisms cannot survive in the environment