Ecosystems and Energy Pyramids

Energy Pyramids

Trophic Levels

• A trophic level represents a position in a food chain, with each level representing a different feeding position
• Typically, there are 4-5 trophic levels in an ecosystem:
  1. Producers (autotrophs): plants, algae, and some bacteria
  2. Primary consumers (herbivores): animals that eat producers
  3. Secondary consumers (carnivores): animals that eat primary consumers
  4. Tertiary consumers (top carnivores): animals that eat secondary consumers
  5. Decomposers (detritivores): organisms that break down dead organic matter

Energy Transfer

• Energy is transferred from one trophic level to the next through consumption
• Energy is lost as heat at each trophic level (approx. 90% lost per level)
• Only 10% of energy is transferred to the next trophic level
• This energy loss is the reason for the pyramid shape of energy pyramids

Food Chain Dynamics

• Food chains are simplified representations of energy transfer between trophic levels
• Food webs are more complex representations of energy transfer, showing multiple food chains interconnected
• Key concepts:
  • Predator-prey relationships: population dynamics of predators and prey affect energy transfer
  • Nutrient cycling: decomposers recycle nutrients, making them available to producers
  • Energy flow: energy is transferred through consumption, but also lost as heat and waste