2.3 Flows of Energy and Matter

Question 1

Define Productivity

Answer 1

The conversion of energy into biomass in a given period of time.

Question 2

Define Ecological Efficiency

Answer 2

The percentage of energy assimilated in one trophic level that is available to be passed to the next.

Question 3

Define Primary Productivity

Answer 3

The production of chemical energy in organic compounds by autotrophs (producers). It is usually measured as biomass per unit area per unit time. For example PP is high in rainforests because there are ample resources: sunlight, water, nutrients, temperature, etc.

Question 4

Define Gross Primary Productivity (GPP)

Answer 4

The total gain in energy or biomass per unit area per unit time fixed by photosynthesis in green plants.

Question 5

Define Net Primary Productivity (NPP)

Answer 5

The total gain by producers in energy or biomass per unit area per unit time minus respiratory losses (R).

Question 6

Define Secondary Productivity

Answer 6

The biomass gained by heterotrophs (consumed) as they feed. It is also usually measured as biomass per unit area per unit time.

Question 7

Define Gross Secondary Productivity (GSP)

Answer 7

The energy of biomass gained by consumers through absorption.

Question 8

Define Net Productivity (NP)

Answer 8

The gain in energy or biomass per unit area per unit time remaining after the deduction of losses through respiration (R) - that is, the biomass available to consumers at subsequent trophic levels.

Question 9

Define Gross Productivity (GP)

Answer 9

The total gain in energy or biomass per unit area per unit time, which could be through photosynthesis in primary producers or absorption in consumers (including that lost to respiration).

Question 10

Define Maximum Sustainable Yield (MSY)

Answer 10

The largest amount of a raw material that can be taken without permanently depleting the stock. It is equivalent to either the net primary or net secondary productivity of the system.

Question 11

Define Organic Compounds

Answer 11

Carbon - containing compounds excluding carbon dioxide and carbonates that are found in the bodies of living organisms. Examples of organic compounds are organisms.

Question 12

Define Inorganic Compounds

Answer 12

Compounds of mineral origin. Examples of inorganic compounds are the atmosphere, soil and fossil fuels.