Topic 10.2 Energy transfer through ecosystems

Question 1

How is energy transferred between trophic levels?

Answer 1

Only a small amount of the energy available to an organism is transferred to the next trophic level. Some is never taken in, some is lost before being transferred.

Question 2

What is meant by net primary productivity

Answer 2

Net primary productivity = energy transferred into biomass (available to the next trophic level)

Question 3

What is meant by gross primary productivity

Answer 3

Gross primary productivity = energy taken in by primary consumers

Question 4

What is the productivity equation

Answer 4

GPP = NPP + R

Question 5

Why is some energy never taken in at each trophic level?

Answer 5

• Some parts of food aren’t eaten
• Some parts of food are indigestable
• Plants can’t use all light energy as some is in the wrong wavelength

Question 6

Why is some energy lost at each trophic level?

Answer 6

Respiration; it is lost as heat

Question 7

How are nutrients recycled within an ecosystem?

Answer 7

By microorganisms

Question 8

Outline the role of microorganisms in the nitrogen cycle

Answer 8

• Nitrogen-fixing bacteria in roots/soil convert gaseous nitrogen into ammonia
• Saprobionts decompose nitrogenous waste into ammonium compounds
• Nitrifying bacteria convert ammonium compounds into nitrates and nitrites

Question 9

Describe the nitrogen cycle

Answer 9

Look at book or photos

Question 10

Describe the carbon cycle

Answer 10

Look at book or photos