Energy Flow in Ecosystems Chapter 3

The capacity to do work Thermodynamics is the study of energy.

1st Law of Thermodynamics When energy is converted from one form to another in a physical or chemical change, no energy is created or destroyed

2nd Law of Thermodynamics Whenever energy is changed from one form to another, we end up with lower-quality or less usable energy than we started with

Initial Energy in Ecosystems Sun – Photosynthesis Chemical – Chemosynthesis Energy is converted by producers(autotrophs) Basis for energy transfer (food chain)

6CO2 + 6H2O —> C6H12O6 + 6O2 carbon water glucose oxygen dioxide Photosynthesis 6CO2 + 6H2O —> C6H12O6 + 6O2 carbon water glucose oxygen dioxide

Chemosynthesis Video in picture

Primary Productivity The fabrication of carbon compounds through photo or chemo- synthesis Gross Primary Productivity Rate at which producers can convert solar energy into biomass Net Primary Productivity Rate at which producers make & store products while accounting for the producers own energy requirements GPP – Respiration = NPP (mg/L/day) or (Kcal/day)

Net Primary Productivity

Trophic Levels Feeding Levels

Trophic Level Organisms Organisms are identified by the food they consume 2nd trophic level and above

Eat producers Primary consumers Example: Deer, rabbits, cows Herbivores Eat producers Primary consumers Example: Deer, rabbits, cows

Carnivores Eat meat (other animals) Secondary+ consumers Example: Lion, frog, ladybug

Eat plants & meat Secondary+ consumers Example: Raccoon, bear, human Omnivores Eat plants & meat Secondary+ consumers Example: Raccoon, bear, human

Other consumers…. Scavengers Decomposers Detritivores Eat dead organisms Decomposers Break down & recycle dead organisms Detritivores Live off detitrus Detritus – dead parts & waste from organisms

Food Webs Arrows represent energy flow Food webs can be disrupted by many factors Keystone species Invasive species