A Viceroy caterpillar feeds on a leaf. One day's feeding consumes 1000 calories worth of leaves. 50% of the calories are lost in its feces and 33% of the calories are used in cellular respiration.How many calories of the original intake are available to add to the caterpillar’s biomass each day?

Question

A.  830 calories
B.  670 calories
C.  500 calories
D.  330 calories
E.  170 calories


Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
 
Gather Content
· What do you already know about energy flow?
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
 
Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

E.  170 calories


Clarify Question
· What is the key concept addressed by the question?
        o This question addresses energy flow.
· What type of thinking is required?
        o This question is asking you to analyze the information given, using logic, to dissect the problem and determine the answer.
 
Gather Content
· What do you already know about energy flow?
        o Energy flow between trophic levels is inefficient. Whenever organisms use chemical-bond or light energy, some of it is converted to heat. Consistent with the Second Law of Thermodynamics, a partial conversion to heat is inevitable. Put another way, animals and plants require chemical-bond energy and light to stay alive, but as they use these forms of energy, they convert them to heat, which they cannot use to stay alive and which they cannot cycle back into the original forms. Fortunately for organisms, the Earth functions as an open system for energy, because light arrives every day from the Sun.
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o One day's feeding consumes 1000 calories worth of leaves.
        o 50% of the calories are lost in its feces – so 500 calories are lost just due to inefficient digestion.
        o 33% of the calories are used in cellular respiration – so 330 calories are used to keep the caterpillar alive.
        o 1000 – 500 – 330 = 170 calories
        o So only 170 calories are available to add to the caterpillar’s biomass each day.
 
Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o The question required you to analyze the information given, using logic, to dissect the problem and determine the answer.
        o Did you recognize that most of the energy from food is lost or used to support respiration?