Surface rule

The surface rule deals with the metabolism of animals and was established by Max Rubner in 1893 .

It states that the specific metabolic rate ( metabolic consumption per kg of body weight ) increases with decreasing body size of the animals. According to this, large animals need less energy per kilogram of body weight than smaller ones. But if the energy consumption is calculated per unit of body surface, it turns out to be almost constant. The surface of two geometrically similar bodies can be expressed as the ⅔ power of the weight multiplied by a constant.

The surface rule says that the metabolism of an animal is proportional to the ⅔ power of the weight of an animal. The surface rule should apply not only (approximately) to homeotherms , but also to poikilothermal vertebrates , invertebrates and also to unicellular organisms .

However, the surface rule is now considered a one-sided explanation. Must be considered z. B. also the behavior of animals, which can place very different energy demands on the metabolism (e.g. hummingbird vs. wren ). It can therefore never make exact statements, but is only considered a rough approximation.

Max Kleiber showed that the energy expenditure of 12 different animal species from the mouse (21 g) to the cattle (600 kg) in an interspecific comparison follows a ¾-power (0.75) rather than a ⅔-power (0.66) . The value he calculated was 0.739, but was rounded up to 0.75. Further research has shown that an exponent of 0.71 must be assumed for mammals. It applies accordingly

${\displaystyle V_{O_{2}}=a\cdot M^{0,71}}$

• ${\displaystyle V_{O_{2}}}$: Oxygen consumption as a measure of energy expenditure
• ${\displaystyle M}$: Body weight in kg
• ${\displaystyle a}$: y-intercept, d. H. the value for a body weight of 1 kg ${\displaystyle V_{O_{2}}}$

See also: Bergmann's rule

literature

• Max Kleiber : Body size and metabolism. In: Hilgardia. Vol. 6, No. 11, 1932, pp. 315-353, doi : 10.3733 / hilg.v06n11p315 .
• Max Kleiber: The energy balance of humans and pets. A textbook of animal energetics. Paul Parey, Hamburg et al. 1967.
• Gerhard Heldmaier , Gerhard Neuweiler : Comparative animal physiology. Volume 2: Gerhard Heldmaier: Vegetative Physiology. Springer, Berlin et al. 2004, ISBN 3-540-00067-4 .

Individual evidence

1. ^ ^{A b c} Handbuch der Zoologie, Handbook of Zoology, all volumes by Timothy R New (hardcover, 1989).
2. ^ Max Kleiber: Body size and metabolism. In: Hilgardia. Vol. 6, No. 11, 1932, pp. 315-353.
3. ↑ Max Kleiber: The energy balance of humans and pets. 1967.
4. ↑ Gerhard Heldmaier, Gerhard Neuweiler: Comparative animal physiology. Volume 2. 2004.