B1.6 Waste Materials from Plants and Animals

Question 1

What conditions do microorganisms work best in?

Answer 1

warm, moist, aerobic conditions.

Question 2

What does the decay process release?

Answer 2

carbon dioxide when microorganisms respire and…

Substances that plants need to grow

eg carbon, nitrogen, mineral ions

Question 3

In a stable community,….

Answer 3

The processes that remove materials are balanced by the processes that return materials. The materials are constantly cycled.

Question 4

What is compost?

Answer 4

The decayed remains of plant and animal matter that can be used as fertiliser.

Question 5

Describe how a compost bin creates ideal conditions for decomposition

Answer 5

• Mesh sides let in air
• Finely shredded waste- larger surface area for microorganisms
• Extra decomposers added -(compost make)
• Warmth generated by decomposition

Question 6

What is the carbon cycle?

Answer 6

The constant cycling of carbon

Question 7

Describe the carbon cycle

Answer 7

• CO2 is removed- plants- photosynthesis- carbon used to make proteins, carbohydrates and fats, which make up the body of plants.
• CO2 released- Carbon becomes CO2 when plants and animals respire
• Plants eaten by animals and animals eaten by other animals, some of the carbon becomes part of the protein and fats that make up their bodies.
• When plants and animals die, microorganisms feed on their bodies
• CO2 released when these organisms respire
• Microorganisms cycled the materials as plant nutrients- all energy originally absorbed by plants has been transferred.
• Combustion of wood and fossil fuels releases CO2 into atmosphere

Question 8

Why do materials decay?

Answer 8

Because they are digested by microorganisms.

Question 9

Describe the part played by green plants and algae in the carbon cycle

Answer 9

They photosynthesise so absorb carbon dioxide from the atmosphere

They release carbon dioxide when they respire

eaten by animals- carbon transferred

decayed by microorganisms when they die- microorganisms respire releasing carbon dioxide

Question 10

Why is respiration much faster in rainforests than in other habitats?

Answer 10

Tropical rainforests are warm and most, ideal conditions for microorganisms so there are lots of them

As it is warm, enzymes work faster

also, there is a lot of material to decay

Question 11

Describe how the carbon in dead animal bodies may be recycled

Answer 11

microorganisms breakdown the bodies, which releases carbon into the soil.

Plants will then absorb this carbon

animals may eat dead animal, so carbon passed on

microorganisms and animals will respire, releasing carbon dioxide

dead animal may fossilise- eventually turn into fossil fuel. When fossil fuel burnt- carbon dioxide is produced

Question 12

Describe how the carbon in dead plants is returned into the air over a few months

Answer 12

microorganisms decompose the plant material

these organisms respire

and release carbon dioxide

Question 13

Why does the decay process release thermal energy?

Answer 13

microorganisms respire which releases thermal energy