Energy transfer in and between organisms - ENERGY TRANSFERS

Question 1

What is each level of the food chain called?

Answer 1

Trophic level

Question 2

What is an apex predator?

Answer 2

The organism at the top of a food chain

Question 3

Define biomass

Answer 3

• Total mass of living material
• In a specific area
• At a given time

Question 4

What is dry biomass and how can we measure it?

Answer 4

The measured biomass when water has been removed
- Bomb calorimetry

Question 5

What does GPP stand for and what is it?

Answer 5

Gross primary production
- Chemical energy store in plant biomass
- In a given area/volume
- At a given time

Question 6

What does NPP stand for and what is it?

Answer 6

Net primary production
- Chemical energy store in plant biomass after respiratory losses

Question 7

Formula for NPP?

Answer 7

NPP = GPP - R (respiratory losses)

Question 8

Why is not all of the NPP passed on to the next trophic level?

Answer 8

• Not all of the organism is consumed
• Some part not being digested so lost in faeces
• Some energy lost in excretory materials
• Some energy losses occur as heat in respiration

Question 9

Formula for net production?

Answer 9

N = I - (F+R)
where:
N = net production
I = chemical energy store of ingested food
F = energy lost in faeces in urine
R = energy lost in respiration

Question 10

Why is only 1% of the light energy from the sun captured by green plants and made available to organisms?

Answer 10

• Over 90% of the sun’s energy is reflected back into space by clouds/dust or absorbed by the atmosphere
• Not all wavelengths of light are able to be absorbed and therefore used via photosynthesis
• Light may not fall on the chlorophyll molecule
• Low levels of CO2 may limit rate of photosynthesis