Chapter 2.2 – Flow of Energy in an Ecosystem

Energy in an Ecosystem  Autotrophs 2.2 Flow of Energy in an Ecosystem Principles of Ecology  Organism that collects energy from sunlight or inorganic substances to produce food  Heterotrophs  Organism that gets it energy requirements by consuming other organisms A lynx is a heterotroph. Chapter 2

 Detritivores eat fragments of dead matter in an ecosystem, and return nutrients to the soil, air, and water where the nutrients can be reused by organisms. Principles of Ecology Fungus 2.2 Flow of Energy in an Ecosystem Chapter 2

Principles of Ecology Models of Energy Flow  Food chains and food webs model the energy flow through an ecosystem.  Each step in a food chain or food web is called a trophic level. 2.2 Flow of Energy in an Ecosystem Chapter 2

Principles of Ecology Food Chains  A food chain is a simple model that shows how energy flows through an ecosystem. 2.2 Flow of Energy in an Ecosystem Chapter 2

Regents Biology  Feeding relationships  all food chains start with energy from the sun  first level of all food chains is plants  most food chains usually go up only 4 or 5 levels  all levels connect to decomposers Food chains Fungi Level 4 Level 3 Level 2 Level 1 Decomposers Producer Primary consumer Secondary consumer Tertiary consumer Top carnivore Carnivore Herbivore Sun Bacteria

Regents Biology Food Chains in the water too.

Principles of Ecology Food Webs  A food web is a model representing the many interconnected food chains and pathways in which energy flows through a group of organisms. 2.2 Flow of Energy in an Ecosystem Chapter 2

Regents Biology But what about decomposers?  Energy flows through but nutrients cycle  nutrients must be recycled to be available for the next generation  decomposers return nutrients to the soil after creatures die  fungi  bacteria nutrientsnutrients decomposers

Principles of Ecology Ecological Pyramids  A diagram that can show the relative amounts of energy, biomass, or numbers of organisms at each trophic level in an organism 2.2 Flow of Energy in an Ecosystem Chapter 2

Regents Biology Food chain pyramid  Loss of energy between levels of food chain  can feed fewer animals in each level 1,000,000, , Numbers

Regents Biology Vegetarians or Meat-eaters??  How many people can Earth support?  If we are meat eaters?  If we are vegetarian? more people can live on Earth fewer people can live on Earth