Trophic Levels
Introduced| English |
|---|
| trophic level/ˈtrəʊfɪk ˈlevl/ |
| producers/prəˈdjuːsəz/ |
| primary consumer/ˈpraɪməri kənˈsuːmə/ |
| decomposers/ˌdiːkəmˈpəʊzəz/ |
Who eats whom
- In any ecosystem, energy passes from one organism to the next by eating.
- Each step in this chain is a feeding level.
- These feeding levels are called trophic levels.
- They stack up from plants at the bottom to top predators at the top.
Producers: the foundation
- Every food chain starts with producers 生产者 — usually green plants.
- They capture the Sun's energy through photosynthesis.
- This makes them the base, or first, trophic level 营养级.
- Everything above them depends on the energy they capture.
A trophic level is…
A trophic level is one feeding step: producers, then primary consumers, then secondary, and so on.
What is at the base of every food chain?
Producers (plants) form the base, capturing the Sun's energy for all levels above.
Consumers stack up
- A primary consumer 初级消费者 eats producers directly (a herbivore).
- A secondary consumer eats primary consumers.
- A tertiary consumer eats secondary consumers, and so on.
- Each higher level is a new trophic level, further from the Sun's energy.
Build the trophic pyramid
Stack the trophic levels - producers at the base feed each higher level of consumers.
An animal that eats a producer directly is a ____ consumer.
A primary consumer eats producers; a secondary consumer eats primary consumers.
Decomposers close the loop
- Decomposers 分解者 — bacteria and fungi — feed on dead organisms.
- They break dead matter down and release its nutrients.
- Those nutrients return to the soil for producers to reuse.
- So decomposers recycle the materials of life at every level.
Decomposers break down dead organisms and recycle their nutrients.
Decomposers (bacteria and fungi) return nutrients from dead matter to the soil.
Select all true statements about trophic levels.
Top predators sit at the top, not the base. The other three are correct.
Do not put the top predator at the bottom. Producers are always the base of a food chain, because they capture the energy everything else needs. The trophic levels build upward from producers to primary, secondary, and higher consumers.
A simple grassland chain:
- Grass (producer) → grasshopper (primary consumer) → frog (secondary consumer) → snake (tertiary consumer).
- Each arrow shows energy passing to the next trophic level.
- Decomposers feed on all of them when they die, recycling the nutrients.
A trophic level is a feeding position in a food chain. Producers form the base; a primary consumer eats producers, and higher consumers stack above. Decomposers feed on dead matter at every level, recycling nutrients back to the producers.