a) Study the flow

a) N_t+1 = N_t + [(B + I) – (D + E)]

b) Three ways to measuring population density of a habitat

i) Per cent cover or biomass for a tree with larger canopy

ii) The number of fishes caught per trap

iii) Pug marks and fecal pellets for tiger census

OR

a)

• Pyramid of energy can never be inverted, is always upright because some energy is always lost as heat at each step when energy flows from a particular trophic level to the next trophic level.

• Energy at a lower trophic level is always more than at a higher level.

• Transfer of energy follows 10 % law of energy transfer in which only 10 % of the energy is transferred to each trophic level from the lower trophic level and the amount of energy decreases at each successive trophic level.

• For their energy demands, organisms at each trophic level depend on those at the lower trophic level.

b)

• Upright pyramid of biomass can be found in forest and grassland ecosystems, while the invented pyramid of biomass is seen in lake and ocean ecosystem as the biomass on the next trophic level is higher than the previous trophic level in an inverted pyramid.