Energy Flow in an Ecosystem

• Food chains and Food Webs


  Ecological concepts that describe the flow of energy and nutrients through ecosystems. They illustrate how organisms in an ecosystem interact with each other based on their feeding relationships.
• Food Chain


  A simplified linear representation of the flow of energy and nutrients in an ecosystem. It typically consists of a series of organisms, with each organism feeding on the one before it.
• Key components of a food chain

  • Producers
  • Primary Consumers
  • Secondary Consumers
  • Tertiary Consumers
  • Decomposers
• Producers


  Autotrophic organisms, usually plants or photosynthetic algae, that convert sunlight into chemical energy through photosynthesis. They are at the base of the food chain and produce their own food.
• Consumers


  Heterotrophic organisms that obtain their energy by consuming other organisms.
• Primary Consumers


  Herbivores that feed on producers (plants).
• Secondary Consumers


  Carnivores that feed on primary consumers.
• Tertiary Consumers


  Carnivores that feed on secondary consumers, and so on.
• Decomposers


  Bacteria and fungi that break down dead organic matter (detritus) and waste products. They play a crucial role in recycling nutrients back into the ecosystem.
• Characteristics of a Food Chain


  • It involves a nutritive interaction between the living organisms of an ecosystem
  • It is always straight
  • It proceeds in a progressive straight line
  • Flow of energy is unidirectional from sun to producers and consumers
  • 80-90% of energy is lost as heat at each transfer
• Food Web


  A network of food chains that become interconnected at various trophic levels to form several feeding connections amongst different organisms of a biotic community. It is a more realistic and intricate representation of the complex interactions among species in an ecosystem.
• Characteristics of a Food Web

  • Food webs are never straight
  • Food webs are formed by interlinking food chains
  • Food webs provide alternative ways of food availability
  • Food webs help in checking the overpopulation of organisms
• Energy Pyramid


  Also known as a trophic or ecological pyramid. The bottom and largest level of the pyramid is the producers and contains the largest amount of energy. As you move up the pyramid, through the trophic levels to primary, secondary and tertiary consumers, the amount of energy decreases and the levels become smaller.
• Removing a species from an ecosystem

  • The organisms that depended on the removed species for food will face starvation, causing population decline or even extinction for these predators
  • If the removed species was a prey animal, its predators might experience a temporary population boom due to lack of predators, but this can't be sustained as the food source will eventually get depleted
  • The disruption can ripple through the food web, for example, if herbivores increase due to lack of predators, they might overgraze on plants, impacting plant populations and the animals that depend on those plants
  • Removing a decomposer species can disrupt the nutrient cycle, affecting plant growth and the entire food web
• Biogeochemical Cycle


  It describes the movement of chemical elements through different media, such as the atmosphere, soil, rocks, bodies of water, and organisms.
• Examples of Biogeochemical Cycles

  • Carbon Cycle
  • Nitrogen Cycle
  • Sulfur Cycle
  • Phosphorus Cycle
• Carbon Cycle


  Carbon flows between each reservoir in an exchange called the carbon cycle, which has slow and fast components. Most of Earth's carbon is stored in rocks and sediments.
• Nitrogen Cycle


  Nitrogen moves through both living and non-living things; the atmosphere, soil, water, plants, animals and bacteria. In order to move through the different parts of the cycle, nitrogen must change forms.
• Sulfur Cycle


  Describes the movement of sulfur through the geosphere and biosphere. Sulfur is released from rocks through weathering and then assimilated by microbes and plants.
• Phosphorus Cycle


  Also referred to as the "Mineral cycle". It is the movement of phosphorus from the organism's environment to organisms and then back to the environment.
• Types of Ecosystems


  • Artificial Ecosystems
  • Natural Ecosystems
• Artificial Ecosystem


  Human-made structures where biotic and abiotic components are made to interact with each other for survival. It is not self-sustaining and can perish without human help. Examples include aquariums, agriculture fields, zoos, etc.
• Natural Ecosystem


  An interaction between the environment and the organisms living in the environment. It occurs naturally in nature and requires no human activity for its functioning. Examples include ponds, rivers, forests, etc.