DECOMPOERS AND DETRIVORES

Question 1

What is the major food chain in most ecosystems?

Answer 1

Saprotrophic

Question 2

What are detrivores?

Answer 2

Invertebrates that eat detritus (Dead organisms or waste material)

Question 3

Give examples of detrivores

Answer 3

Earthworm, millipede and woodlouse

Question 4

How is detritus digested by detrivores?

Answer 4

Internally using enzymes secreted into the gut

Question 5

What happens to undigested detritus?

Answer 5

It becomes fragmented into smaller pieces as it is passed through the digestive system. This passes out as faeces and forms humus

Question 6

What is the result of fragmentation?

Answer 6

It increases the surface area of the material available for decomposers to work on.

Question 7

What is decomposition?

Answer 7

The chemical breakdown of organic matter in detritus

Question 8

Which organisms are decomposers?

Answer 8

Bacteria and fungi

Question 9

What are the major decomposers of plant material?

Answer 9

Fungi

Question 10

Where do fungi get their energy from?

Answer 10

By breaking down organic matter such as cellulose in dead plants or herbivore droppings.

Question 11

What are the major decomposers of dead animals?

Answer 11

Bacteria

Question 12

What type of digestion do decomposers use?

Answer 12

External

Question 13

What do the secreted enzymes break the complex organic molecules into?

Answer 13

Smaller molecules and nutrient ions which can then be absorbed into the cell.

Question 14

What are the nutrient ions also available to?

Answer 14

Plants

Question 15

What is the result of the decomposition of the decomposers?

Answer 15

All the nutrients are recycled into the soil

Question 16

What is another word for decomposition and why?

Answer 16

Mineralisation because nutrients are released into the soil

Question 17

Why are soil decomposers essential for an ecosystem?

Answer 17

They are the only organisms able to make mineral nutrients available again for use by plants.

Question 18

What would be the result of no soil decomposers?

Answer 18

A build up of dead material and plant growth would cease due to lack of nutrient availability

Question 19

Where else can nutrients become available?

Answer 19

The very slow erosion of weathering rocks

Question 20

What are two limiting factors for decomposition?

Answer 20

Low temperature (enzymes work slower)
Nitrogen availability (microbes need nitrogen to make enzymes and other cell proteins)

Question 21

What is the cycle of a nutrient?

Answer 21

Nutrients are fixed into organisms , transformed into various compounds as they pass along the food chain, and are then broken down into simple forms that can be fixed again

Question 22

How is the CO2 fixed by photosynthesis recycled back into the atmosphere?

Answer 22

Respiration

Question 23

How do other nutrient elements become available to the community again?

Answer 23

Compounds have to be broken down be decomposer organisms in the soil

Question 24

What are the three basic stages of a nutrient cycle?

Answer 24

Fixation
Transformation
Loss

Question 25

Describe fixation

Answer 25

The nutrient is taken from the abiotic environment and is fixed into a food web as an organic compound

Question 26

Describe transformation

Answer 26

The organic compound can be changed into other organic molecules

Question 27

Describe loss

Answer 27

The organic compounds are lost from the food web; they are broken down to release simple organic units back to the abiotic environment