ecology - pyramids of biomass

Question 1

how can we measure the mass of all the organisms at a certain trophic level?

Answer 1

by biomass
eg to find biomass of caterpillars in a food chain, collect the, kill them, dry them and weigh them for dry biomass.
no scientist wants to kill animals so instead look up data they need in scientific journals

Question 2

why is dry biomass better than a wet biomass?

Answer 2

the moisture content of organisms can vary widely and produce inaccurate results

Question 3

how much light energy that falls on producers is absorbed + used for photosynthesis?

Answer 3

1%

Question 4

why does biomass for each trophic level decrease?

Answer 4

• biomass is a living tissues of an organism including proteins, lipids, and carbohydrates
• only 10% of the biomass at one trophic level passes to the next level causing number of organisms at each trophic level to decrease. very few food chains with a large number of different trophic levels

Question 5

why does only around 10% (1g) or another percentage of the biomass from a secondary consumer (caterpillar in this case) end up in the biomass of a tertiary consumer (bird in this case)

Answer 5

• not all of the material that the bird ingests is absorbed. some egested as faeces
• some of the biomass that is absorbed is converted into waste products of metabolism and is released (humans=urea)
• large amount of biomass is used by bird for respiration to release energy. aerobic respiration also produces carbon dioxide and water so some of biomass is used to produce waste compounds. energy from respiration used for example in movement. maintain constant body temp in mammals and birds

Question 6

how to calculate efficiency of biomass transfer?

Answer 6

efficiency = gain in biomass / total biomass intake.
to calculate as percentage multiply by 100

• could reflect how animals moves around and maintains a constant body temperature