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3/4 - the power of Life by WBE Theory – ep. 1

Empowerment Coaching Krakow Blog-The power of Life by WBE Theory 1

Today we are starting a series of three extremely interesting articles explaining the basic laws of biology governing living organisms on our planet. Among them, the rule of the power of 3/4 comes to the fore. What are its consequences? For example, if a man wanted to use the surface tension of water to walk on its surface like a water strider, he would have to stretch his limbs for a length of seven kilometers (!).


In biology, the concept of "the same, only bigger" has no existence

The respiratory system of insects consists of a system of gaps - tracheas and spiracles - holes scattered over the surface of the body through which air under atmospheric pressure is pushed into the body. It is a simple and reliable system, but it only works well over a distance of a few centimeters. 300 million years ago, in Carboniferous, while dragonflies with a wingspan of 75 centimeters flew over the earth, those days the air contained more oxygen than today.

Today, a two-meter cockroach is the same as a strangled cockroach. And also a cockroach with broken legs, because if the insect was enlarged to the size of an elephant, its legs would collapse under the weight of the body.

The strength of bones and muscles depends on their thickness. If we enlarge an animal four times, its bone strength increases sixteen times. However, the weight will grow more, because it is proportional to the volume, i.e. as much as 64 times. Larger bones, though stronger, will not hold him.

Simple scaling laws don't work in biology

The dung beetle can carry a load of 400 times its weight, but a human can hardly lift another human, and an elephant will not be able to walk with another elephant on its back. In turn, miniaturized octopuses would sink in water like in honey, unable to move - because at these sizes they would be bound by the forces of water cohesion.

If a human wanted to use the surface tension of the water to walk on its surface like a water explorer, he would have to stretch his limbs seven kilometers (!).

These examples show that in biology, the concept of "the same, only greater" is irrelevant. Knowledge of the rules governing ant life is of no use to us when we want to infer anything about whales. Elephants are not big ants. Size matters and that's enough!

How different the laws of physics are against this background. Big and small balls fall from the tower in the same way, and gravity does not treat bread crumbs and large space bodies differently. Simple scaling laws do not work in biology.

Are there any principles in the science of life that would work on all scales of magnitude?

When looking for fundamental laws, let's start with what drives life. Where do animals get their energy from? From burning in the cells. The greater their volume, the more cells they have, and the more energy and, by the way, more heat. However, you need to know how to properly manage it, which is why the cooling capacity seems to be equally important. This in turn depends on the surface of the body through which the heat can be radiated.

Small animals have a large body surface area in relation to their volume, so they do well where excess heat is a problem, for example in equatorial regions, and much worse in cold climates. That is why there are large animals in the polar regions: seals, walruses, or bears, not mice or butterflies. Relatively small penguins "cheat" nature, gathering in herds during the winter, thanks to which they become one large organism.

What is the conclusion of this? The smaller the animal, the greater its heat loss and the more calories it has to burn to replenish the lost energy.

The mouse spends almost the entire day eating and consumes twice as much food as it weighs. The amount of food that an elephant is satisfied with is - per kilogram of body weight - almost 30 times smaller. A 50-gram mouse body produces 5 kilocalories of heat per day (100 calories per gram of body). Five-ton elephant - just 60,000 calories (12 calories per gram of body). If the elephant kept the same metabolic rate as the mouse, it would boil in its own skin!

The three-quarters rule is stubborn

The fact that large animals have a slower metabolism than small animals was observed in 1932 by Max Kleiber, a biologist at the University of California. Animal wards live long and unhurriedly. Their hearts beat slowly. In a minute, an elephant takes 6 breaths, a human - 20, a mouse - 150.

By giving some more generously, and others more sparingly, mother nature tried to be just in one thing: she granted every creature, regardless of species and size, a billion heartbeats. Toddlers use them very quickly, so their lives are short - mice two years, rabbits five years. On the other hand, giants spread their potential longer - elephants live 40 years, and giant Galapagos tortoises for almost two centuries.

When Max Kleber compared the metabolic rate of mice, elephants, and nearly all the other animals he knew, he found it to be proportional to the creature's mass raised to a power of three-quarters (that is, the fourth-degree from mass to the third power), and lifespan depends on one-fourth of the mass.

It was the first universal law of nature - applicable to everyone, without exception, for 21 orders of magnitude, from bacteria to cetaceans. And also a very strange law. Why? Because where did the mysterious three-fourths exponent come from?

About this in the next episode ...


The author of the article is Irena Cieślińska, and it was originally published in Polish in "Przekrój Nauki" magazine, no. 8/2008

Translation from Polish: Empowerment Coaching

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