Why are there typically a larger number of producers than tertiary consumers in an ecosystem?

• A. Because tertiary consumers can photosynthesize to obtain energy directly.
• B. Because producers require more sunlight than tertiary consumers.
• C. Because tertiary consumers reproduce more rapidly than producers.
• D. Because energy is lost at each trophic level, limiting the amount available to higher-level consumers.

Answer: (D)

Verified step by step guidance

1. Understand the concept of trophic levels: In an ecosystem, organisms are categorized into trophic levels based on their role in the food chain. Producers (like plants and algae) form the base, followed by primary consumers, secondary consumers, and tertiary consumers.
2. Recognize the energy flow in ecosystems: Energy enters the ecosystem through producers, which convert sunlight into chemical energy via photosynthesis. This energy is then transferred to consumers as they feed on other organisms.
3. Learn about energy loss at each trophic level: According to the 10% rule, only about 10% of the energy at one trophic level is passed on to the next level. The rest is lost as heat, waste, or used for metabolic processes.
4. Understand why producers are more abundant: Since energy diminishes as it moves up the trophic levels, there must be a larger number of producers to support the energy needs of higher-level consumers, including tertiary consumers.
5. Conclude that energy limitations restrict population sizes: Tertiary consumers are fewer in number because the energy available to them is significantly reduced compared to lower trophic levels, making it unsustainable for large populations at the top of the food chain.