This excel workbook illustrates a number of allometric equations in animal growth. The workbook also calculates an allometric equation with graphical output for data entered by the user. Brain mass, skeletal mass, and metabolic rate compared to body size are a few of the variables illustrated. The user can compare proportionality coefficients and exponents for different species groups to determine how they are different. The user can compare allometric equations of gathered data to those found in the workbook.

Allometric Growth

Galileo developed the idea of allometric growth in his Discoursi, published while under house arrest in 1638. He noted that the bones of larger animals grow thicker at a faster rate than they grow longer compared to the same bone in smaller animals. Thus, the ratio of “height:girth” decreases as animals grow larger (Swarthmore).

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Evolution and Development I: Size and Shape, Brown University