Energy Flow Through Ecosystems

Ecology Developed by Ernst Haeckel Eco-house -logy-study The study of the interactions among organisms and between organisms and their abiotic environment. Composed of biotic (living) and abiotic (nonliving or physical)

Levels of biological organization in ecology Biosphere Landscapes Ecosystems Communites Populations Individual Organism

Energy Roles Energy Role in an Ecosystem Stored=potential Motion=kinetic Thermodynamics is the study of energy Closed system: no energy exchange with surroundings Open system: energy exchanged with surroundings

Laws of Thermodynamics First Law: Energy can neither be created nor destroyed, but transformed from one form to another. In biological terms: organisms do not create energy but use energy from the environment. Sun-photosynthesis-food Second Law: When energy is converted from one form to another, usable energy is lost. Heat is an examples in biological orgranisms.

Some Energy Roles The sun: provides energy (light energy) Producers: harness energy from the sun ex. plants Consumers: organisms that eat something else ex. animals Decomposers: return energy to the environment ex. fungus, bacteria

Producers Plants harness energy from the sun through photosynthesis- Autotroph 6 CO2 + 12 H2O Light C6H12O6 + 6 O2 + 6 H2O They are the base of every food chain Source of food for all other animals

Consumers Relies on producer for their energy needs. Heterotroph 4 Types Herbivore: eats only plants Ex. Cows, horses Carnivore: eats only meat Ex. Polar bear Obnivore: eats plants and animals Ex. Humans, grizzly bears Scavenger: carnivore that feeds on bodies of dead organisms Ex. Vultures

Decomposer Decomposers break down wastes and dead organisms and return the raw materials to the environment-Heterotroph Ex. Bacteria, fungi

Energy flow through biological systems

Food Chains Food Chain: series of events in which one organism eats another and obtains energy

Food Chains Continued Arrows always points in the direction of energy flow 1st organism is always the producer 2nd organism is the consumer that eats the producer Primary consumer 3rd organism is the consumer that eats the 1st level consumer Secondary consumer And so on…..

Energy passes onto next level Energy Flow 100 The energy available to each trophic level will always equal the amount entering the trophic level, minus total losses to that level (due to metabolic activity, death, excretion, etc) Energy lost as heat will be lost from the ecosystem. Other loses becaome part of the detritus and may be utilized by other organisms in the ecosystem. Trophic Level Energy lost as heat Energy lost to detritus 65 10 25 Energy passes onto next level

Energy (ecological) Pyramid The percentage of energy transferred from one trophic level to the next is called the trophic effeciancy. 5-20% An average figure of 10% is often used-the 10% rule. Energy Pyramid shows the amounts of energy that moves from one level to the next Can also have a pyramid of biomass

Sample Energy Pyramid

Productivity of Producers Gross primary productivity (GPP) Rate at which energy is captured during photsynthesis. Net primary productivity (NPP) The energy that remains in plant tissues after respiration. Only the energy represented by NPP is avaible for consumers.

Net Primary Productivities NPP= GPP- Plant respiration The NPP for a particular river ecosystem is measured at 8,833 kcal/m2/year. Respiration by the aquatic producers is estimated at 11,977 kcal/m2/year. Calculate the GPP for this ecosystem.

8,833 kcal/m2/year + 11,997 kcal/m2/year = 20,830 kcal/m2/year