Sub-linear/log type scaling for different factors. Together this should lead to different optimal sizes for different animal types and niches.

One would suppose body mass/ weight that a 3-d entity has would be constrained by the ability of the skeleton to grow and support it. Also by the ability of the organs to perform functions on a level that encourages or discourages proportionate growth. Perhaps the availability and richness of food sources would also be a limiting factor in the development of size constraints.

Respiratory systems. The further from the outmost membrane (the larger and “deeper” an organism), the more time and energy require to diffuse oxygen throughout said organism. If an organism is nearly two dimensional, theoretically this wouldn’t be a constraint at all: oxygen and carbon dioxide could diffuse freely and easily without any required effort from the organism (i.e breathing cause by internal pressure fluctuations).

There’d be a point in a three dimensional organism where the amount of effort required to carry oxygen throughout the entire body is too much to justify its size, placing a size constraint on the organism. To my understanding, this scales with atmospheric oxygen in insects, which is why earth used to have quite literally giant insects. The more atmospheric oxygen, the larger life as a whole can grow. Definitely speaking a little out of ignorance here, so feel free to correct me if I have the wrong impression.

It’s the square cube law. Whenever you increase the size of an animal, its surface area can square but the volume will cube – this is why from a point onwards you can’t just breathe through your skin like ants do and instead you need specialized organs like lungs.

In terms of height: they are limited by the height of the tallest trees (the underwater animals will rather grow in length and width because of the pressure exerted onto their bodies) and the abundance of resources to feed themselves.
It will also depend on the altitude they are at.

Hello Ladies and Gentlemen,

Flat, opened, and closed- Euclidean and non-Euclidean forms.

As surface area and volume get larger, there is predator and prey population checks. The survival of the beautiful kicks in of course.

Availability and nutrient dense foods are factors, legends in Nunavut saying the giants grew large on a diet of fish.

The square cube law says surface area can square but the volume will cube- this means weight carrying and the power of the skeletons needed to carry the weight.

Animals are limited by the weight the skeleton can carry…on land.

Water animals encounter bouyancy.

Dinosaurs had huge bones. This was good to survive pre- bombardment power lift requirements. Whales still have large bones.

Survival in cold weather is seen in small animal production in the far north. Farmers grow rabbits as easier to feed than cattle.

Cuando un animal tridimensional aumenta de tamaño, su volumen (y, por lo tanto, su masa y metabolismo) aumenta más rápido que su área de superficie. Esto se debe a que el volumen crece en función del cubo de la longitud lineal, mientras que el área de superficie solo crece en función del cuadrado de la longitud lineal.

Esta diferencia en la tasa de crecimiento entre volumen y área de superficie tiene importantes implicaciones para la forma en que los animales obtienen y utilizan recursos. Por ejemplo, la capacidad de un organismo para intercambiar gases, nutrientes y calor con su entorno está fuertemente influenciada por su superficie externa. En organismos planos, como hojas de plantas o aletas de peces muy delgadas, la distancia entre las células o tejidos y el ambiente circundante es relativamente corta, lo que facilita el intercambio de sustancias. En contraste, en animales tridimensionales, como mamíferos o aves, la distancia entre las células internas y el ambiente externo es mucho mayor, lo que puede limitar la eficiencia de los procesos de intercambio.

Esto puede influir en aspectos como la capacidad de termorregulación, la eficiencia metabólica y la capacidad de obtener suficiente oxígeno y nutrientes. Los organismos tridimensionales deben desarrollar adaptaciones especializadas, como sistemas circulatorios complejos o estructuras respiratorias eficientes, para superar estas restricciones de escala y mantener un equilibrio metabólico adecuado a medida que crecen.