Allometry is the study of the relationship of body size to
Also, there are changes in allometry as a
where is the scaling exponent of the law.
JBS Haldane's 1926 essay On being the right size gives an overview of the way size interacts with body structure. Haldane's thesis is that sheer size very often defines what bodily equipment an animal must have:
Many of his examples are based on the square-cube law. If an animal's length is doubled, its surface area will be squared and its weight cubed. This alone causes allometric changes in any evolutionary lineage where successive species get larger of smaller. There are many such lineages.
The bigger an animal gets, the more would they have to change their physical shape, but the weaker they would become.