Question

trophic levels and biomass
with less energy at higher trophic levels, there are usually fewer organisms as well. organisms tend to be larger in size at higher trophic levels, but their smaller numbers result in less biomass. biomass is the total mass of organisms at a trophic level. the decrease in biomass from lower to higher levels is also represented by the figure above.
questions

1. what is a trophic level?

1. which trophic level includes humans?

1. what types of organisms are in the first trophic level? give an example.

1. assume that producers in an ecosystem have 1,000,000 kilocalories of energy. how much energy is available to primary consumers?

1. which trophic level has the greatest biomass?

1. what percent of energy is lost from one trophic level to the next as heat?

Explanation:

1. A trophic level is a position an organism occupies in a food chain or food web, representing its feeding stage.
2. Humans can be in the third or higher trophic levels (secondary or higher consumers) as they eat primary consumers (e.g., herbivores) or other secondary consumers.
3. Producers (autotrophs) are in the first trophic level. An example is plants (which perform photosynthesis).
4. According to the 10% - rule (only about 10% of energy is passed from one trophic level to the next), if producers have 1,000,000 kilocalories, primary consumers get \(1000000\times0.1 = 100000\) kilocalories.
5. The first trophic level (producers) has the greatest biomass as they convert sunlight (or other energy sources) into biomass and support higher - level consumers.
6. About 90% of energy is lost from one trophic level to the next as heat (due to metabolic processes like respiration).

Answer:

1. A position an organism occupies in a food chain or web representing its feeding stage.
2. Third or higher (secondary or higher consumers).
3. Producers (autotrophs); e.g., plants.
4. 100,000 kilocalories.
5. The first trophic level (producers).
6. 90%.