Food chains are sometimes short because a. only a single species of herbivore feeds on each plant species. b. local extinction of a species causes extinction of the other species in its food chain. c. most of the energy in a trophic level is lost as energy passes to the next higher level. d. most producers are inedible.

Verified step by step guidance

1. Identify the key concept: The question is asking why food chains are sometimes short, which relates to the efficiency of energy transfer across different trophic levels in an ecosystem.
2. Analyze the options: Consider how each option relates to the length of food chains and the efficiency of energy transfer.
3. Evaluate option c: This option states that most of the energy in a trophic level is lost as energy passes to the next higher level. Recall that according to the 10% rule in ecology, only about 10% of the energy is transferred from one trophic level to the next, with the rest lost primarily as heat.
4. Compare with other options: Options a, b, and d do not directly address the general principle of energy transfer efficiency in ecosystems, which is a fundamental reason for the shortness of many food chains.
5. Conclude that the correct answer is c: Since energy loss at each trophic level restricts the length of sustainable food chains, option c is the most accurate explanation for why food chains are sometimes short.

Key Concepts

Trophic Levels

Trophic levels represent the hierarchical positions in a food chain, where each level consists of organisms that share the same function in the ecosystem. The primary producers (plants) form the first level, followed by herbivores (primary consumers) and then carnivores (secondary and tertiary consumers). Understanding these levels is crucial for analyzing energy flow and species interactions within an ecosystem.

Energy Transfer in Ecosystems

Energy transfer in ecosystems follows the 10% rule, where only about 10% of the energy from one trophic level is passed on to the next. This significant energy loss occurs due to metabolic processes, heat production, and waste. As a result, food chains tend to be short, as there is insufficient energy to support many levels of consumers.

Local Extinction and Food Web Dynamics

Local extinction refers to the disappearance of a species from a specific area, which can disrupt the food web and lead to cascading effects on other species. When a key species is lost, it can result in the decline or extinction of dependent species, thereby shortening food chains. This concept highlights the interconnectedness of species within an ecosystem and the potential fragility of food webs.