How is the flow of energy in an ecosystem characterized?

Unidirectional, from producers to consumers

The correct answer is Option (1) - Unidirectional, from producers to consumers.

The flow of energy in an ecosystem is primarily unidirectional, moving from producers to consumers. This flow follows the fundamental principle of energy transfer in ecosystems, known as the "10% rule" or the "trophic transfer efficiency."

Producers, such as plants, algae, and some bacteria, are the primary source of energy in an ecosystem. They capture solar energy through photosynthesis and convert it into chemical energy stored in organic compounds. This energy is then passed on to consumers, which are organisms that obtain their energy by consuming other organisms.

When consumers feed on producers (herbivores) or other consumers (carnivores or omnivores), they obtain a portion of the energy stored in the consumed organism's tissues. However, energy is not transferred completely from one trophic level to the next. According to the 10% rule, only approximately 10% of the energy from one trophic level is passed on to the next trophic level. The remaining energy is lost as heat, used for metabolic processes.

This unidirectional flow of energy from producers to consumers continues through different trophic levels in a food chain or food web. Primary consumers (herbivores) obtain energy from producers, secondary consumers obtain energy from primary consumers, and so on.