Energy Flow in Ecosystems Food Chains, Food Webs, & Energy Pyramids
2 types of ENERGY: Potential = STORED energy Kinetic = energy in MOTION
Photosynthesis: the chemical reaction where green plants use water and carbon dioxide and light from the sun to make glucose and oxygen. ENERGY is stored in glucose
It all starts with the SUN Photosynthesis = potential (stored) energy Equation: CO2 + H2O + sunlight C6H12O6 (glucose)+ O2
Fox eats Rabbit that ate plant.
Food Chains Food chains- use pictures or words and arrows to show the movement of energy in an ecosystem Trophic level- indicates the position that the organism occupies in the food chain Arrows- point TO the animal that is doing the eating!! (where the energy is going!)
Types of Food Chains Aquatic: Water-related food chains with sea plants and animals Terrestrial: Land-related food chains with land plants and animals
All food chains begin with the SUN!
Follow the food chain from producer to top level consumer. Note: There’s something wrong. What is it? Follow the food chain from producer to top level consumer.
Why does this look more like a “cycle” than a chain? Let’s discuss this one in detail.
In this food chain, what is the producer? What is the first level consumer? What is the second level consumer? Is the polar bear the 3rd level consumer? Explain.
This picture shows the trophic levels.
Trophic Levels
Food Webs Food webs- a group of interconnecting food chains They describe the complex patterns of energy flow in an ecosystem
Find a few food chains in this food web.
Find as many food chains as you can!
Food Webs are EASY!
Energy Pyramids An energy pyramid shows the amount of energy that moves from one trophic level to another in a food chain. The most energy is available at the producer level of the pyramid. The availability of energy decreases as it moves up the energy pyramid.
The most energy is at the producer level – the base of the pyramid.
10% Rule: only about 10% of energy is passed to the next level of the pyramid. Other 90%?? Gets used by organism or lost as heat energy
Units for Energy: Kcal, Joules (J), calories
Making a Model Let’s make a model of an energy pyramid. The model you will construct will be simple. It will show trophic levels, the names of organisms, and the energy available. Make sure you follow all instructions for proper completion of the model.