Some call “metabolic ecology” the maverick theory that might explain life:
Big animals have relatively slower metabolic rates — this is why a shrew must eat more than its body weight each day to survive, but an elephant eats only one-50th of its bulk per day. The net result is that both species share the same number of heartbeats in a lifetime.This remarkable phenomenon can be expressed mathematically as a scaling law, which states that the metabolic rate of a species is proportional to its mass raised to the power of three-quarters.
This formula holds true for almost every living organism. From whales to trees, the relationship is the same — but no-one understood why.
Then, in 1997, Geoffrey West, a physicist at the Santa Fe Institute in New Mexico, working with ecologists Jim Brown and Brian Enquist, published a theory. They argued that the scaling is the result of the fractal-like structure of the network of blood vessels that supply nutrients to the cells in an animal’s body. A similar fractal geometry can be seen in plant veins.
West, Brown and Enquist believe that metabolic rate is the conductor of life’s orchestra, setting the tempo for a host of other processes. Understand it, and we can predict many other things about a creature — how quickly it will grow and how many offspring it will have. They argue that their theory can predict the properties of large-scale ecological networks, such as forests.