Class 12 Biology Chapter 12
Ecosystem
Important Questions

Explanation:
Energy flow in an ecosystem is a fundamental ecological process, illustrating how energy is passed from one organism to another through food chains and webs.

• Food Chains: A food chain is a linear sequence that illustrates how energy and nutrients pass from one organism to another. It begins with producers (like plants) that convert solar energy into chemical energy via photosynthesis. This energy is then transferred to primary consumers (herbivores), and then to secondary and tertiary consumers (carnivores and omnivores). Each step in this chain represents a trophic level.
• Food Webs: A food web is a more complex structure that connects multiple food chains within an ecosystem. It shows the intricate feeding relationships among various organisms, highlighting how they interact and depend on one another for energy.
• Energy Flow: Energy flow is unidirectional; it starts with solar energy captured by producers and moves through the trophic levels. However, energy is lost at each level, primarily as heat, due to metabolic processes. Only about 10% of the energy at one trophic level is passed to the next, a phenomenon known as the 10% rule. This significant energy loss explains the smaller number of organisms and biomass present at higher trophic levels.
• Trophic Levels: Organisms in a food chain or web are categorized into trophic levels: First Trophic Level: Primary producers (plants). Second Trophic Level: Primary consumers (herbivores). Third Trophic Level: Secondary consumers (carnivores). Higher Trophic Levels: Tertiary and quaternary consumers.

The study of energy flow provides insight into the functioning of ecosystems, the importance of each species, and the balance and sustainability of ecological communities.