Q50.6-3ITD - Campbell Biology

Question

The slopes of the flying and swimming lines are very similar. Based on your answer to question 2, if the energy cost of a 2-g swimming animal is 1.2 cal/(kg .m), what is the estimated energy cost of a 2-kg swimming animal?

Step-by-Step Solution

Answer

A 2-kg swimming animal's expected energy expenditure will be 1200 cal/(kg .m).

Step 1: The slopes of the flying and swimming lines

The oxygen consumption rate or carbon dioxide production was studied in animals that worked on treadmills, swam in water flumes, or soared in wind tunnels. A tube linked to a plastic face mask, for example, collected gases released by a bird during flying. 

Based on these, Schmidt-Nielsen computed the amount of energy based on measurements. Each animal was utilized to deliver a specific quantity of body mass over a particular distance the predetermined distance [calories/(kilogram. meter)].

Step 2: Relation among the energy cost and swimming animal

An animal swimming through water meets with resistance or drag; it must supply a force that equals the drag to propel itself. The pain on an aquatic animal is a complex function of shape, size, and speed. 

The importance of shape is expressed in what is commonly known as "streamlining." so well-known from fish and whales and regrettably absent in man. The animal's size enters primarily as the surface area in contact with water, for as water moves over a surface, the boundary layer dissipates energy.

Step 3: Determination of the estimated energy cost of a 2 kg swimming animal

The other two methods can plot all data items if a linear scale is requested to be plotted on the graph rather than a log scale. 

Plotting the numbers on the left and right axes is not appropriate in this example because both variables have a wide range. As a result, an attempt should be made to divide the axes.

Researchers can use the ratio of the metabolic rate in calories per grams per hour at a specific speed in kilometers per hour to that speed to calculate the cost of transportation in these units. So, as given in the question, the energy cost is 1.2 cal/(kg .m) for the 2g weight.

$$\begin{gathered} 2g=1.2cal/(kg.m) \\ 1g=\frac{1.2}{2} \\ 1g=0.6cal/(kg.m) \end{gathered}$$

$$\begin{gathered} For the 2kg weight, the energy \cos t will be: \\ 2kg=0.6\times 2000\left[1kg=1000g\right] \\ =1200cal/(kg.m) \end{gathered}$$

Hence, 1200 cal/(kg .m) is the estimated energy cost of a 2-kg swimming animal.