[问答题]
The diagram below shows the food web in a salt marsh, o
xq-40x av9imi 8gjgf1*obv: p ne of the mos
ewcpgtdv.s me*y x70 zom4 w,+;j 99wut productive habitats on Ear
d4j*wm+7 ;tsz9peceuvwx90.mog yw, th.
1.The numbers on the arrows show the percentage of gross primary production that flows into different trophic levels or is used in plant respiration.
2.Define gross and net primary production.
Identify the herbivores shown in the system.
3.If the energy available to consumers from producers in organic compounds is 300 g m$^{-2}$yr$^{-1}$(dry), calculate the amount of energy that is lost by export to the tide.1
4.(1)The table below shows the NPP for three trophic levels in a food web. Draw a pyramid of energy from the information in this table, labelling it appropriately with the trophic levels and corresponding NPP values (rounded to 3 significant figures as in the table).
(2)Outline a limitation of the ecological pyramid of energy.
5.Explain how a food web provides a more accurate representation of an ecosystem’s feeding relationships than a food chain.
