gru4l3.2 flow of energy 10% rule - fighting...
TRANSCRIPT
Objective!
The student will (TSW) evaluate the flow of energy within an ecosystem and calculate how energy is divided in a food pyramid using the
10% rule.
Why are we learning this?!
Ecology helps us understand the connections and relationships between living organisms and their physical
environment.
Energy Flow!
Energy flow is the transfer of energy within an ecosystem.
(Energy comes from eating things.)
Energy Pyramids!
Energy Pyramids show the amount of energy transferred as you move up the
food chain. Energy is measured in kcal (kilo calories)
or J (joules).
10% Rule!
Only 10% of the energy in a food web is passed from one trophic level to the next.
As we move up the trophic levels, more energy is lost to the environment as heat.
10% Rule!
How do we find out what the new amount of energy will be?
Move the decimal point one space to the
left as you go up the trophic levels.
DIRECTIONS
• Voices at a Level Zero
• Complete the ‘Guided Practice’
• Answer in complete sentences • Raise your hand if you have
questions
DIRECTIONS
• Voices at a Level Zero
• Complete the ‘Independent Practice’
• Answer in complete sentences • Raise your hand if you have
questions
Grass: 1000kcal
Cows and Rabbits
Wolves
Example 1
So what if the grass received 1000 kcal from the sun? How much energy would cows and rabbits have? How much energy would wolves have?
Grass: 1000kcal
Cows and Rabbits: 100kcal
Wolves: 10kcal
Example 2
What percent of the grass’s energy moved on to the next trophic level? What percent was lost?
Grass: 3450kcal
Cows and Rabbits: 345kcal
Wolves: 34.5kcal
Example 2
Whatifthegrassnowreceived3450kcalofenergyfromthesun?Howmuchenergywouldbecarriedintoeachtrophiclevel?