In AP Environmental Science, a secondary consumer is an organism that eats primary consumers (herbivores). It occupies the third trophic level of a food chain and is usually a carnivore or omnivore, as described in CED topic 1.11.
A secondary consumer is whatever eats the plant-eaters. Producers make their own food, primary consumers (herbivores) eat the producers, and then secondary consumers eat those herbivores. That puts them at the third trophic level in a food chain.
Most secondary consumers are carnivores, but omnivores count too if they're eating animals that ate plants. Think of a frog eating a grasshopper, or a small fish eating zooplankton. In the food web model from EK ENG-1.D.1, the same organism can act as a secondary consumer in one chain and something else in another. A snake that eats a frog is a tertiary consumer, but a bird that eats that same frog might be a secondary consumer in a different chain. The label depends on the chain, not the animal itself.
This term lives in Unit 1: The Living World: Ecosystems, specifically topic 1.11 Food Chains and Food Webs. It supports learning objective AP Enviro 1.11.A, which asks you to describe food chains and food webs and identify their members by trophic level. You can't label a trophic level correctly without knowing where secondary consumers fit.
It also connects to EK ENG-1.D.2 on feedback loops. Remove or add a species and the whole web shifts. If you wipe out a secondary consumer, the herbivores it ate can explode in number, which then crushes the producers. Energy flow and the 10% rule both run through this concept, so getting trophic levels right is foundational for the rest of the unit.
Keep studying AP Environmental Science Unit 1
Primary Consumer (Unit 1)
Primary consumers are the herbivores that eat producers, and they're exactly what secondary consumers feed on. To find the secondary consumer in any chain, first find the herbivore, then find whatever eats it.
Carnivore and Omnivore (Unit 1)
These describe HOW an organism eats; secondary consumer describes WHERE it sits in the chain. A secondary consumer is usually a carnivore, but an omnivore can be one too when it's eating a plant-eater.
Feedback Loops (Unit 1)
EK ENG-1.D.2 says removing or adding a species ripples through the web. Knock out a secondary consumer and herbivore populations can boom, triggering negative feedback that hammers the producer level.
Bioaccumulation and Biomagnification (Units 1, 8)
Toxins concentrate as you move up trophic levels, so a secondary consumer carries more accumulated toxin than the primary consumer it ate. This links food web structure directly to pollution effects later in the course.
Expect this on multiple-choice questions that hand you a food chain and ask which trophic level an organism occupies, or which arrow shows energy flowing into a secondary consumer. A released question gives a marine chain (phytoplankton to zooplankton to small fish to tuna) and asks where a bioaccumulating toxin concentrates most, so you need to track which organism is the secondary consumer versus the top predator. The 2018 SAQ Q3 used an Arctic food web stimulus and asked you to read organisms by trophic level. On FRQs, you'll typically identify roles in a given web and then explain what happens if one species is removed, which is where feedback loops come back in.
A primary consumer eats producers (it's the herbivore, second trophic level). A secondary consumer eats primary consumers (it's the carnivore or omnivore one level up, third trophic level). The quick test: if it eats plants, it's primary; if it eats the plant-eater, it's secondary.
A secondary consumer eats primary consumers and occupies the third trophic level of a food chain.
Secondary consumers are carnivores or omnivores, but the label is about position in the chain, not just diet type.
The same organism can be a secondary consumer in one food chain and a different trophic level in another chain.
Removing a secondary consumer can trigger feedback loops, letting herbivore populations grow and damaging the producer level (EK ENG-1.D.2).
Toxins that bioaccumulate get more concentrated in secondary consumers than in the primary consumers they eat.
It's an organism that eats primary consumers (herbivores), placing it at the third trophic level of a food chain. It's usually a carnivore or omnivore, like a frog eating a grasshopper.
No. It's usually a carnivore, but an omnivore can be a secondary consumer when it's eating an animal that ate plants. The defining feature is that it eats a primary consumer, not what else it might eat.
A primary consumer eats producers (plants), sitting at the second trophic level. A secondary consumer eats the primary consumer, sitting one level higher at the third trophic level.
Yes, because trophic level depends on the food chain, not the organism. An animal that eats a herbivore in one chain is a secondary consumer, but if it eats a small carnivore in another chain, it's a tertiary consumer there.
Toxins concentrate as energy moves up trophic levels, so secondary consumers carry more accumulated toxin than the primary consumers they eat. Top predators above them carry the most, which is a common multiple-choice setup.