How Energy Flows through Living Systems

A small group of people are A small group of people are stranded stranded on a barren desert island. on a barren desert island.

They have 500 They have 500 bushels of wheat bushels of wheat

and one cow. What and one cow. What should they do to should they do to

survive the greatest survive the greatest length of time?length of time?

A. Eat the cow and then eat the wheat.

B. Drink the cows milk, eat the cow, and

then eat the wheat.

C. Don’t feed the cow, drink the cows milk, eat the cow when milk

production stops and then eat the wheat.

D. Feed the wheat to the cow and drink

the milk

E. Feed the wheat to the cow, drink the

milk, and then eat the cow.

F. Eat the wheat and then eat the cow.

Think about the question

yourself.

Which answers do you think are the best ones?

Which ones make the

most sense?

Why?

A. Eat the cow and then eat the wheat.

B. Drink the cows milk, eat the cow,

and then eat the wheat.

C. Don’t feed the cow, drink the cows

milk, eat the cow when milk production stops and then eat

the wheat.

D. Feed the wheat to the cow and drink

the milk

E. Feed the wheat to the cow, drink

the milk, and then eat the cow.

F. Eat the wheat and then eat the cow.

Now that you have had Now that you have had the opportunity to come the opportunity to come up with your own up with your own hypothesis, get together hypothesis, get together with the people at your with the people at your table and come up with a table and come up with a table group consensus table group consensus on how to survive for the on how to survive for the longest time.longest time.

A. Eat the cow and then eat the wheat.

B. Drink the cows milk, eat the cow,

and then eat the wheat.

C. Don’t feed the cow, drink the cows milk, eat the cow when milk

production stops and then eat the

wheat.

D. Feed the wheat to the cow and drink the milk

E. Feed the wheat to the cow, drink

the milk, and then eat the cow.

F. Eat the wheat and then eat the cow.

Table groups, now is your time to Table groups, now is your time to debate your conclusion with the debate your conclusion with the other table groups.other table groups.

Is there a class consensus?Is there a class consensus?

If so What is it?If so What is it?

Energy transfer from one trophic level to Energy transfer from one trophic level to another to another is extremely another to another is extremely inefficient. If the cow eats the wheat, inefficient. If the cow eats the wheat, then much of the energy from the wheat then much of the energy from the wheat will be lost as heat and cow feces and will be lost as heat and cow feces and will be unusable to the peoplewill be unusable to the people

If the cow is alive it is going through If the cow is alive it is going through metabolism, converting organic molecules metabolism, converting organic molecules into waste products, ATP and heat. These into waste products, ATP and heat. These energy conversions reduce the cows energy conversions reduce the cows energy value to the people.energy value to the people.

Choices D & E are not goodChoices D & E are not good because of the inefficiency of because of the inefficiency of energy transfer between energy transfer between trophic levelstrophic levels

A. Eat the cow and then eat the wheat.

B. Drink the cows milk, eat the cow, and then eat

the wheat.

C. Don’t feed the cow, drink the cows milk, eat the cow when milk production stops and then eat the wheat.

D. Feed the wheat to the cow and drink the milk.

E. Feed the wheat to the cow, drink the milk, and

then eat the cow.

F. Eat the wheat and then eat the cow.

Choice F is not a good choiceChoice F is not a good choice because it keeps the cow alive because it keeps the cow alive burning off calories.burning off calories.

A. Eat the cow and then eat the wheat.

B. Drink the cows milk, eat the cow, and then eat

the wheat.

C. Don’t feed the cow, drink the cows milk, eat the cow when milk production stops and then eat the wheat.

D. Feed the wheat to the cow and drink the milk.

E. Feed the wheat to the cow, drink the milk, and

then eat the cow.

F. Eat the wheat and then eat the cow.

The best choices are A & B. The best choices are A & B. Choice AChoice A allows for the allows for the consumption consumption of the cows energy before much of of the cows energy before much of it is wasted by the cows it is wasted by the cows metabolism. metabolism. Choice BChoice B is similar, but it allows is similar, but it allows for the harvesting of the energy in the cowfor the harvesting of the energy in the cow’’s s milk. It may be a better choice than A if the milk. It may be a better choice than A if the cow is milked right away. But if the cow cow is milked right away. But if the cow continues to produce milk over time (continues to produce milk over time (Choice Choice CC) it will waste energy in the process.) it will waste energy in the process.A. Eat the cow and then eat the wheat.

B. Drink the cows milk, eat the cow, and then eat

the wheat.

C. Don’t feed the cow, drink the cows milk, eat the cow when milk production stops and then eat the wheat.

Green Plants

Some Protists

6 CO2 and 6 H2OCarbon dioxide & Water

C6H12O6 and 6 O2

Glucose & Oxygen

Leaves

Chloroplasts

Autotrophs

Producers

The process cells use to break down glucose into ATP (energy) the cells can use.

C6H12O6 and 6 O2

Glucose & Oxygen

6 CO2 and 6 H2OCarbon dioxide & Water

ATP

Money

Mitochondria

It allows them to convert the glucose produced during photosynthesis into ATP (energy) the cells need.

When you break it down into its When you break it down into its simplest form, Water energy and gas simplest form, Water energy and gas come in during photosynthesis come in during photosynthesis and are released and are released by cellular respirationby cellular respiration

6CO2 + 6H2O + C6H12O6 + 6O2 6CO2 + 6H2O +

Photosynthesis

Cellular Respiration

If you stop to think about it, If you stop to think about it, cellular respiration the exact cellular respiration the exact opposite of photosynthesis.opposite of photosynthesis.

Use your understanding of Use your understanding of Photosynthesis and Cellular Photosynthesis and Cellular

Respiration to create a T-Chart Respiration to create a T-Chart comparing the two pathwayscomparing the two pathways

PhotosynthesPhotosynthesisis

CellularCellularRespirationRespiration

PhotosynthesisPhotosynthesis Cellular Cellular RespirationRespiration

Which cellular organelle is Which cellular organelle is responsible for responsible for photosynthesis?photosynthesis?

Which cellular organelle is Which cellular organelle is responsible for cellular responsible for cellular

Respirations?Respirations?

Photosynthesis takes Photosynthesis takes place in _____.place in _____.

A. PlantsA. Plants

B. AnimalsB. Animals

C. BothC. Both

Cellular Respiration Cellular Respiration takes place in takes takes place in takes

place in _____.place in _____.

A. PlantsA. Plants

B. AnimalsB. Animals

C. BothC. Both

Which of the following best Which of the following best describes the part of the describes the part of the

bioenergetics pathway shown bioenergetics pathway shown below.below.

CC66HH1212OO66 + 6O + 6O22

A.A.It represents the reactants of It represents the reactants of photosynthesis photosynthesis

B. It represents the reactants B. It represents the reactants of cellular respiration. of cellular respiration.

C. BothC. Both

Which cellular organelle is Which cellular organelle is responsible for responsible for photosynthesis?photosynthesis?

Which cellular organelle is Which cellular organelle is responsible for cellular responsible for cellular

Respirations?Respirations?

Photosynthesis takes Photosynthesis takes place in _____.place in _____.

A. PlantsA. Plants

B. AnimalsB. Animals

C. BothC. Both

Cellular Respiration Cellular Respiration takes place in takes takes place in takes

place in _____.place in _____.

A. PlantsA. Plants

B. AnimalsB. Animals

C. BothC. Both

Which of the following best Which of the following best describes the part of the describes the part of the

bioenergetics pathway shown bioenergetics pathway shown below.below.

CC66HH1212OO66 + 6O + 6O22

A.A.It represents the reactants of It represents the reactants of photosynthesis photosynthesis

B. It represents the reactants B. It represents the reactants of cellular respiration. of cellular respiration.

C. BothC. Both