Question

part 1:
below is a food web. using the key label each organism with its trophic level.
a - autotroph
1 - primary consumer
2 - secondary consumer
3 - tertiary consumer
4 - quaternary consumer

Explanation:

• Algae: Autotrophs (A) as they produce their own food through photosynthesis.
• Phytoplankton: Autotrophs (A) for the same reason as algae.
• Limpets: Primary Consumers (1) as they feed on algae (producers).
• Mussels: Primary Consumers (1) if they filter - feed on phytoplankton (producers).
• Zooplankton: Primary Consumers (1) as they feed on phytoplankton.
• Starfish: Secondary Consumers (2) if they feed on primary consumers like limpets.
• Fish: Can be secondary (2) if they feed on zooplankton (primary consumers) or higher - level consumers depending on their diet in the web.
• Seagull: Can be secondary (2) if it feeds on fish (which may be primary consumers in some parts of the web) or higher - level depending on its diet.
• Octopus: Can be tertiary (3) if it feeds on secondary consumers like starfish.
• Human: Can be at various levels (secondary (2) if fishing for primary - consumer fish, tertiary (3) if eating octopus (tertiary consumer) etc.)

Answer:

• Algae: A
• Phytoplankton: A
• Limpets: 1
• Mussels: 1
• Zooplankton: 1
• Starfish: 2
• Fish: 2
• Seagull: 2
• Octopus: 3
• Human: Varies (e.g., 2, 3)