What do animals use energy for?

As a group, draw an arrow diagram of what happens to the energy (food) an

animal eats

Include categories from board

Energy Flow

• C = gross energy in food• P = production• R = metabolic

(respiratory)• U = energy lost in urine• F = energy lost in feces• A = amount of

assimilated energy

C = P + R + U + F A = P + R + U

Energy Ratios

C = P + R + U + F A = P + R + U

ecological efficiency

Energy flow through an ecosystem

Is what we eat efficient from an ecosystem perspective?

Should we eat large mammals? (cows?)

Is it sustainable with population growth?

• Average human 3,000 Cal/day

• Human needs 30,000 Cal Beef– Beef needs 300,000 Cal corn

• 3.3ha produces enough corn to – feed one person if that person

eats cows– Feed 10 people if they eat

corn

Where does the energy come from to produce offspring?

C = P + R + U + F

Zebra Finches

Tony WilliamsSimon Fraser University