Question

The transfer of energy from one trophic level to the next is known as what?

• A. Nutrient Cycling
• B. Decomposition
• C. Energy Flow
• D. Production

Answer 1

Answer:

C. Energy Flow

Energy Flow in Ecosystems

• Energy Flow refers to the transfer of energy from one trophic level to the next within an ecosystem. It is a fundamental concept in ecology.
• The ultimate source of energy for almost all ecosystems on Earth is the Sun.

• Trophic Levels:

  • Producers (Autotrophs): Organisms, primarily green plants and some bacteria, that produce their own food using sunlight (photosynthesis) or chemical reactions (chemosynthesis). They form the first trophic level.
  • Primary Consumers (Herbivores): Organisms that feed directly on producers. Examples include deer, rabbits, and grasshoppers. They occupy the second trophic level.
  • Secondary Consumers (Carnivores/Omnivores): Organisms that feed on primary consumers. Examples include snakes eating mice, or foxes eating rabbits. They are at the third trophic level.
  • Tertiary Consumers (Top Carnivores/Omnivores): Organisms that feed on secondary consumers. Examples include eagles eating snakes or lions eating gazelles. They occupy the fourth trophic level.
  • Decomposers (Detritivores): Organisms like bacteria and fungi that break down dead organic matter from all trophic levels, returning nutrients to the soil. They play a crucial role in nutrient cycling, though they are often depicted separately from the main trophic pyramid.

• Key Principles of Energy Flow:

  • Unidirectional Flow: Energy flows in a single direction, from the sun to producers and then through successive trophic levels. It does not cycle back.
  • Ten Percent Law (Lindeman's Law): Only about 10% of the energy from one trophic level is transferred to the next higher trophic level. The remaining 90% is lost, primarily as heat during metabolic processes (respiration) or remains unconsumed. This law was proposed by Raymond Lindeman in 1942.
  • Due to the 10% law, the amount of energy significantly decreases at higher trophic levels, limiting the number of trophic levels in an ecosystem (typically 4-5 levels).
  • This concept is often represented by an Energy Pyramid (or Ecological Pyramid), which illustrates the decreasing amount of energy, biomass, or number of organisms at each successive trophic level.
  • Energy flow is distinct from nutrient cycling; while energy flows unidirectionally and dissipates, nutrients are continuously recycled within the ecosystem.