MP Board · Class 10 · Science · Our EnvironmentWhat is an ecosystem? Explain its various components with examples and describe the flow of energy through different trophic levels in an ecosystem.

Introduction to Ecosystem\nAn ecosystem is a self-sustaining structural and functional unit of the biosphere, consisting of a community of living organisms interacting with each other and with their non-living physical environment. It can be natural (like a forest, lake, or desert) or artificial (like an aquarium or a crop field).

Components of an Ecosystem\nAn ecosystem is broadly divided into two main components:

• Biotic Components (Living Factors): These include all the living organisms present in an ecosystem. They are further classified into three categories based on how they obtain their food:

  • Producers (Autotrophs): These include green plants and blue-green algae that can manufacture their own food through photosynthesis using sunlight, water, and carbon dioxide. Example: Grass, trees.
  • Consumers (Heterotrophs): These are organisms that depend directly or indirectly on producers for food. They include herbivores (plant-eaters like deer), carnivores (meat-eaters like lions), and omnivores (eat both plants and animals like humans).
  • Decomposers (Saprotrophs): These include micro-organisms like bacteria and fungi that break down the complex organic remains and waste products of dead organisms into simpler inorganic substances, returning nutrients to the soil.

• Abiotic Components (Non-living Factors): These are the physical and chemical factors of the environment that influence living organisms. Examples include temperature, light, rainfall, soil, minerals, wind, and humidity.

Flow of Energy in an Ecosystem\nEnergy flow in an ecosystem is always unidirectional and follows the laws of thermodynamics:

• Sunlight to Producers: Green plants capture about 1% of the total sunlight falling on their leaves and convert it into chemical energy through photosynthesis.
• Trophic Levels: The transfer of food or energy takes place through successive steps or trophic levels in a food chain. Producers form the first trophic level, herbivores form the second trophic level, primary carnivores form the third, and top carnivores form the fourth trophic level.
• Ten Percent Law: According to Lindeman's Ten Percent Law, only 10% of the energy is transferred from one trophic level to the next, while the remaining 90% is lost to the environment as heat during metabolic processes, respiration, and movement. Due to this rapid loss of energy, food chains generally consist of only 3 to 4 trophic levels, as insufficient energy remains to support any further organisms beyond the top carnivore.