1. Showing energy transfer among organisms (biosphere!)
Food Webs:
Showing energy transfer among organisms (biosphere!)

2. Organisms & Energy: Required for life processes
Sources: Sun & other organisms
All organisms need energy.
Organisms are constantly using energy to survive.
Life processes: photosynthesis, cellular respiration, growth, digestion, movement, metabolism, reproduction, etc.
Sun is the original source of nearly all energy used by organisms on Earth.
Plants/Algae can directly convert sunlight into energy whereas all other organisms must obtain energy through eating other organisms.
Reflection Question:
List 4 sources of energy for you in the last 24 hours.
AMV

3. Law of Conservation of Matter:
Matter is neither created nor destroyed, only transformed from one form to another
Energy & matter are related:
Part of what organisms use energy for is to create matter – grow their tissues!
The cells/tissues that make up organisms are stored energy sources … for that organism and for any consumer of that organism.
During chemical and physical reactions, no mass is permanently lost or magically created. It may have been in a different form:
EXAMPLE: 300 pound tree is burned. When it is done burning, ashes remain on the ground. When you weigh those ashes, they total 10 pounds. Where are the other 290 pounds? Released into the atmosphere as smoke/gas. There are still 300 pounds of mass, it has just been transformed.

4. Law of Conservation of Energy: (1st Law of Thermodynamics)
Energy and mass are related:
Transforming energy is constantly happening:
EXAMPLES:
Photosynthesis
Electricity
Reflection Question:
How does your body show the law of conservation of energy?
I consume food (stored chemical energy) and use it for all my movement, etc.
Energy is neither created nor destroyed, only transformed from one form to another

5. 2nd Law of Thermodynamics:
When energy is changed from one form to another, some of it is lost to the surrounding environment.
Energy transfer is not 100% efficient.
Examples of energy transfer not being 100% efficient:
Burning coal for electricity: ~33% of the energy stored in the coal is actually used to generate the electricity, the rest is released to the larger environment and therefore not useable in the electricity generators.
How does this relate to a food chain?
Organisms consume energy for their life processes.
The only portion of their energy that is available to other organisms is the part that the organism used to grow their tissues.
Energy that’s “lost to the larger environment” includes, for EXAMPLE:
Heat released by cellular & metabolic processes
Motion used for movement
Digestion
Reproduction
And so on …
Reflection Question:
How do we use the energy we consume?
AMV – movement, maintaining body temperature, digestion, growth
If a person is being eaten by a polar bear, what portion of the total energy we’ve consumed would be available as energy to the polar bear?
Only growth portion as the rest was used and released to larger environment

6. Food Web Requirements:
Food Web Requirements:
Original energy source (SUN!)
Producers
Consumers
Decomposers
Soil (or water for aquatic)
Arrows – showing energy flow
Layered by trophic level
Meadow practice
Aquatic practice
Hoo eats who?