Disclaimer: I did see a previous question touching on something like this but what I’m confused about was NOT addressed so hopefully this is allowed.
They say that the surface area volume ratio limits how big things can grow because surface area scales as a square while volume scales as a cube, so the ratio of volume to surface area goes up as you get bigger. Fair enough. BUT: how is this not just a matter of what units you’re using?
For example, a 1x1x1 ft cube has a surface area to volume ratio of 6sq. Ft to 1 cubic foot, so 6:1. A 1x1x1 meter cube has a ratio of 6:1 too but the units are meters. Couldn’t you always define your units so that you have a 6:1 ratio with any size of cube?
To bring it back to the actual question, wouldn’t your ratio be essentially the same no matter how big your object is? Imagine you expanded everything in the universe by the same amount but kept your unit of measurement the same, you wouldn’t suddenly hit some limit where it stops working right? Does it have something to do with the size of molecules and proteins etc? Please help I am so confused
In: 0
No, because you’ll be using the same units for both the regular size, the square, and the cube. If you use different units for each in order to get the same numbers out it doesn’t change the fundamental fact that heat production in a mammal scales with the cube while its ability to dissipate heat scales with the square, so if you double the size of the creature without making any other changes, it will tend to overheat due to producing 8x as much heat but only having 4x the surface area to get rid of it.
Creatures that don’t produce their own heat, such as lizards, don’t have the same problem, which is why dinosaurs were able to get so large. Creatures that live in the sea are also less affected because water is a much more efficient conductor of heat than air is, which is why the largest animal that has ever lived is today’s blue whale.
Latest Answers