Trophic levels

What are trophic levels?

The different levels of a food chain.

What is the first trophic level?

Always a producer (plant/algae)

Why is the first trophic level called producers?

Because they are able to use photosynthesis to produce their own food. This is where all the energy in the food chain comes from.

What is the second trophic level made up of?

Primary consumers. The first organisms in the food chain that consume other organisms.

What can primary producers also be called?

Herbivores because they only eat plants and algae.

What is the third trophic level made up of?

Secondary consumers. The second level of consumers in a chain.

They are carnivores because they eat other animals.

What is the 4th trophic level made up of?

Tertiary consumers. Also carnivores.

What is important about different food chains in different ecosystems?

They will have different numbers of trophic levels, but usually won’t get more than 4 or 5.

What happens when you go up a trophic level?

Some of the energy gets lost, so there’s not enough energy to sustain organisms in a higher trophic level.

Between each trophic level, how much energy gets passed on to the next level?

About 10%.

What are the carnivores at the very top of the chain who have no predators called?

Apex predators.

What organisms do not fit neatly into this pattern?

Omnivores. They eat both producers and other animals.

Where are omnivores generally placed?

In trophic level 3 because they eat primary consumers. However, because they also eat producers its not really a perfect fit.

What are detritivores and decomposers?

Decomposers - bacteria, fungi

Detritivores - small animals e.g. worms.

What do detritivores and decomposers do?

• Decompose the dead plant and animal matter in the environment.

• This allows them to recycle nutrients from animals and plants back into the ground, and then used again by producers.