Energy Transfer in Ecosystems

Ten Percent Rule Overview

• The Ten Percent Rule states that only 10% of energy is stored when one organism is consumed by another in an energy pyramid.
• This rule illustrates energy transfer inefficiencies within ecosystems.

Primary Producers

• Primary producers occupy the base level of the energy pyramid.
• They primarily convert light energy into chemical energy (food) through photosynthesis.

Energy Transfer between Organisms

• When a first-level consumer eats a primary producer, only 10% of the producer's energy is stored as the consumer's energy.
• The remaining 90% of energy is lost, mainly as heat or used for metabolic processes.

Structure of the Pyramid of Energy

• The levels include:
  • Primary Producer
  • First-Level Consumer
  • Second-Level Consumer
  • Third-Level Consumer

Energy Transfer Calculation

• If energy flows from a primary producer to a third-level consumer through two intermediaries:
  • 10% from primary producer to first-level consumer
  • 1% from first-level consumer to second-level consumer
  • 0.1% from second-level consumer to third-level consumer
• Thus, the third-level consumer retains only 0.1% of the original energy from the primary producer.

Energy Flow in Ecosystems

• Energy enters ecosystems from the sun.
• It circulates through ecosystems via food webs, illustrating ecological relationships and energy transfer.

Basic Energy Requirement

• All organisms need energy to survive, which is fundamental for life processes, growth, and reproduction.