Energy Flow in ecosystems?

1. Energy Flow in ecosystems? Most of Earth’s energy comes from the sun Some of Earth’s inhabitants have adapted to convert solar energy to chemical potential energy in carbon bonds. Food chains trace a single flow of energy and show trophic levels-the levels of nourishment in a food chain The primary producers Energy Flow in Ecosystems

2. First law of thermodynamics • Energy cannot be created or destroyed • It can be converted to other forms Energy Flow in Ecosystems

3. Second law of thermodynamics • There is loss of energy with conversion, usually in the form of heat • The heat energy still exists, but cannot be used • Example: Internal combustion engines in cars are 25% efficient in converting chemical energy to kinetic energy; the rest is not used or is lost as heat. Energy Flow in Ecosystems

4. THINK ABOUT IT • What happens to energy stored in body tissues when one organism eats another? • Energy moves from the “eaten” to the “eater.” Where it goes from there depends on who eats whom! Energy Flow in Ecosystems

5. How does energy flow through ecosystems? • Energy flows through an ecosystem in a one-way stream, from primary producers to various consumers. • Many types of consumers • Herbivores - eat plants, algae, or autotrophic bacteria, are the primary consumers of an ecosystem • Carnivores - which eat the consumers from the levels below • Secondary consumers include many small mammals, such as rodents, and small fishes that eat zooplankton • Tertiary consumers, such as snakes, eat mice and other secondary consumers • Quaternary consumers include hawks and killer whales. Energy Flow in Ecosystems

6. Omnivores • Detritivores • Decomposers • Scavengers • Derive their energy from the dead material left by all trophic levels • Digest complex organic chemicals into inorganic nutrients that are used by producers • Completes the cycle of matter. Energy Flow in Ecosystems

7. Quaternary, tertiary, and secondary consumers Tertiary and secondary consumers Secondary and primary consumers Primary consumers Producers (plants) Energy Flow in Ecosystems

8. Producers Also called autotrophs Obtain energy from nonliving sources Most capture energy during photosynthesis to make simple sugars Consumers Also called heterotrophs Obtain energy from living or once-living organisms Ways of obtaining energy Energy Flow in Ecosystems

9. How producers get their energy? PhotosynthesisChemosynthesis • Source of energy: • Chemicals • Sulfer-rich salt marsh • Source of energy: • Sunlight Use non-living sources for energy Examples: -Green plants -Cyanobacteria Examples: -Deep sea vent bacteria CO2 + water  sugars CO2 + water + H2S + O2  sugars + sulfuric acid Energy Flow in Ecosystems

10. Energy from the Sun is stored as GLUCOSE • Created during photosynthesis from carbon dioxide • Broken down during cellular respiration (in consumers) and released as carbon dioxide Glucose Energy Flow in Ecosystems

11. Associated terms with energy production and energy flow. • Primary production: • Fixation of energy by autotrophs in an ecosystem. • Rate of primary production: • Amount of energy fixed over a given period of time. • Gross primary production (GPP): • Total amount of energy fixed by autotrophs. • Net primary production (NPP): • Amount of energy leftover after autotrophs have met their metabolic needs. Energy Flow in Ecosystems

12. Primary Productivity in Ecosystems • Gross primary productivity (GPP) • The rate at which an ecosystem's producers capture and store a given amount of chemical energy as biomass in a given length of time. • Net primary productivity (NPP) • Rate at which all the plants in an ecosystem produce net useful chemical energy; equal to the difference between the rate at which the plants in an ecosystem produce useful chemical energy (gross primary productivity) and the rate at which they use some of that energy through cellular respiration. • (NPP = GPP – Respiration) Energy Flow in Ecosystems

13. Secondary productivity: • The rate of production of new biomass by consumers, i.e., the rate at which consumers convert organic material into new biomass of consumers. • Note that secondary production simply involves the repackaging of energy previously captured by producers--no additional energy is introduced into the food chain. • And, since there are multiple levels of consumers and no new energy is being captured and introduced into the system, the modifiers gross and net are not very appropriate and are not usually used.

14. Coral reefs and Marine ecosystems have the highest primary productivity? WHY? • Highest rates of primary production by marine phytoplankton are generally concentrated in areas with higher levels of nutrient availability. • Highest rates found along continental margins. • Nutrient run-off from land. • Sediment disturbance • Open ocean tends to be nutrient poor. • Vertical mixing main nutrient source. Energy Flow in Ecosystems

15. What controls primary productivity? • Terrestrial primary production generally increases with moisture and temperature • Rosenwitz studied net primary production across biomes • Compare NPP to actual evapotranspiration Energy Flow in Ecosystems

16. What controls primary productivity? • Terrestrial and aquatic primary production is also limited by nutrient availability Energy Flow in Ecosystems