Question

a herbivore ingests 6 kcal of energy. it gains 1 kcal in biomass, uses 2 kcal in respiration, and egests 2 kcal as waste. how much energy is lost as heat?

Explanation:

Step1: Recall energy - balance principle

The energy ingested is equal to the sum of energy in different forms (biomass, respiration, waste, and heat loss). Let the energy lost as heat be $x$.
The energy ingested $E_{in}=6$ kcal, energy in biomass $E_{biomass} = 1$ kcal, energy in respiration $E_{respiration}=2$ kcal, and energy in waste $E_{waste}=2$ kcal.
So, $E_{in}=E_{biomass}+E_{respiration}+E_{waste}+x$.

Step2: Solve for $x$

Substitute the known values into the equation: $6 = 1+2 + 2+x$.
First, simplify the right - hand side: $1+2 + 2=5$.
Then, we have $6=5 + x$.
Subtract 5 from both sides of the equation: $x=6 - 5$.
$x = 1$ kcal.

Answer:

1