2.3.21 (HL)—Nitrogen cycle flows

Label a nitrogen arrow by what moves and where: uptake enters producers, consumption enters consumers, death and waste enter detritus, and decomposition returns inorganic forms.

Photosynthesis builds carbon compounds but does not itself name a nitrogen flow; mineral uptake and ammonification identify the nitrogen-specific steps.

Nitrate → plant protein is mineral uptake; dead plant protein → ammonium is ammonification.

Excretion/defecation transfers nitrogen to waste; it is not decomposition until microbes process that waste.

Do not label every arrow ‘decomposition’; reserve it for breakdown of dead organic material.