6.5.2 transfer of biomass

Question 1

define trophic level

Answer 1

the level at which an organism feeds in a food chain (each level of the food chain)

Question 2

how can tracking how biomass changes in a food chain help

Answer 2

helps track movement of materials & energy through a food chain

Question 3

describe biomass transfer through an ecosystem

Answer 3

• at each trophic level, living organisms require energy (produced by respiration) & some energy is converted to heat/materials lost in carbon dioxide/water
• biomass also lost in dead organisms & waste material = available to decomposers
• biomass is less at higher levels of the food chain

Question 4

how can the efficiency of biomass transfer be calculated

Answer 4

• draw pyramid of biomass = area of each bar is proportional to dry mass of all organisms at trophic level

Question 5

how does an ecologist draw a pyramid of biomass

Answer 5

• collects all organisms
• puts them in 80 degrees oven until all water has been evaporated (check this by finding mass of organisms)
• once mass stops reducing = certain all water has been removed

Question 6

what do ecologists do instead of construct a pyramid of biomass (destructive to ecosystem)

Answer 6

measure wet mass of organisms & calculate dry mass on basis of previously published data

Question 7

how can the efficiency of biomass transfer between trophic levels be calculated

Answer 7

(biomass as higher trophic level divided by biomass at lower trophic level) x 100