Ecology - Energy Transfer

Question 1

Key terms

Answer 1

Biomass - Amount of organic compound left over that’s stored in organism that gives energy to the consumer (meat in grams from cow to human)

Gross primary productivity - Rate of production of organic compound by plant via photosynthesis within a certain area of time

Net Primary Productivity - plant biomass, organic compound available in tissue for consumer

Question 2

Light absorption by plant

Answer 2

Plant = producers
-obtain organic compound via photosynthesis, most plant use >10% of light fall on them

Due to:
-some light reflected or pass through plant and not touch chlorophyll
-not useful light
-energy loss in evaporation

Question 3

Calculating efficiency of plant

Answer 3

Gross primary productivity - glucose use in respiration = net primary productivity for plant to eat

Question 4

Calculating energy efficiency of transfer

Answer 4

Efficiency of process (%) = (quantity of energy utilised such as growth/ quantity of energy consumed) x 100

Question 5

Energy transfer from producers to primary consumers

Answer 5

-Less than 10% of energy obtained from plant used for organic compound for growth, repair, or metabolic reaction. Secondary productivity.

Due to:
-Not all grass is consumed
-energy from plant lost in respiration (eg heat loss)
-cellulose hard to digest so pooed out

% efficiency of transfer can be worked out using formula of last slide

Question 6

Energy transfer from primary to secondary consumer (cow to human)

Answer 6

Secondary productivity greater (around 20% of biomass consumed used to convert to organic compound)

Due to:
Protein easier to break down - less loss in urine or faeces

But loss due to:
-respiration
-some biomass not eaten (bone)
-protein denature in cooking

Question 7

Role of decomposers

Answer 7

-Bacteria or fungi

-Digest remains of organisms and give energy back to producer to grow (ions)

Question 8

Why food chain/ trophic level can’t be too high

Answer 8

-energy is lost at each level, while as trophic level increase organism require more energy

Question 9

How organism can maintain biomass energy

Answer 9

-farm animal in barn (heat less loss)
-gastric fermentation/ eat faeces
-smaller organism need less heat for surface area