Question

Use your knowledge of the relative energy content among trophic levels to answer the following question: A larger human population could be supported if all humans derived their food from which trophic level? A. Producers B. Primary consumers C. Secondary consumers D. Tertiary consumers E. Quaternary consumers

Short answer

A. Producers

Step-by-step solution

- Understanding Trophic Levels

Trophic levels refer to the different stages in a food chain, starting with producers (e.g., plants) that produce energy and followed by various levels of consumers that eat the preceding level for energy. Producers are at the first trophic level, primary consumers (herbivores) are at the second, secondary consumers (carnivores that eat herbivores) at the third, tertiary consumers at the fourth, and quaternary consumers at the fifth.

- Energy Transfer Between Trophic Levels

As energy moves up the trophic levels, from producers to various consumers, the available energy decreases significantly due to energy being lost as heat, through respiration, and other biological processes. Typically, only about 10% of the energy from one trophic level is passed to the next.

- Population Support and Energy Availability

More energy is available at the lower trophic levels. Since producers convert solar energy into usable chemical energy efficiently and are at the base of the food chain, they contain the most energy. Eating lower on the food chain (e.g., consuming producers directly) means there is more energy available to support a larger population.

- Answering the Question

Based on the principles of energy transfer and availability, a larger human population could be supported if all humans derived their food from producers. This is because producers contain the maximum amount of energy available in the food chain.

Key concepts

energy transfer

Energy transfer in trophic levels is foundational to understanding ecosystems. When organisms consume others as food, energy is transferred from one trophic level to the next. However, not all energy is efficiently transferred.
Approximately only 10% of the energy at one trophic level is available to the next level. This is due to various losses such as heat, metabolic processes, and waste. For example, plants (producers) capture energy from the sun through photosynthesis. When herbivores (primary consumers) eat the plants, they only obtain about 10% of the energy the plants captured.
This 10% rule continues up the food chain, with energy diminishing at each subsequent level due to continuous losses. Therefore, primary consumers get more energy from their food compared to secondary consumers, and so on. This explains why top predators are fewer in number compared to species lower on the food chain.

food chain

The food chain is a sequence showing the flow of energy from one organism to another. It begins with producers, who generate energy through photosynthesis. From there, the energy moves to primary consumers, which are herbivores that eat the plants.
Next are secondary consumers, which are carnivores that eat herbivores. This is followed by tertiary consumers, which prey on secondary consumers, and finally quaternary consumers, which are top predators feeding on tertiary consumers. Each step in the food chain represents a different trophic level.
Understanding the food chain is essential as it shows how energy and nutrients move through an ecosystem. It also reveals the interdependence among organisms. If one level of the food chain is disrupted, it can have ripple effects throughout the ecosystem, affecting every other level.

producers

Producers form the base of the food chain and are crucial for energy production in an ecosystem. They are typically plants or algae that can manufacture their own food through the process of photosynthesis. Using sunlight, water, and carbon dioxide, producers create glucose and oxygen, which serve as energy and building material for themselves and other organisms.
Since producers convert solar energy directly into usable chemical energy, they contain the highest amount of available energy in the food chain. This is why more energy is accessible at the level of producers compared to any other trophic level.
In terms of human dietary choices, relying on producers for food can support a larger population. Consuming plants directly allows us to take in more of the original energy captured from the sun, thereby making it a more efficient energy source compared to consuming meat, which involves higher trophic levels.