Gereon Janzing, geobotánico y etnobotánico
Gereon Janzing, geobotánico y etnobotánico

Logistic growth

When a population of a species in an ecosystem is a lot smaller than the potence of the sytem, it can grow exponentially. But the exponential growth comes to an end as the difference between the potence and the population increases (as a rough rule of thumb, when it reaches half the potence). After that the population approaches the potence asymptotically. That combination of a phase of exponential growth and a phase of asymptotic growth is called logistic growth. In practice, of course, growth does not always follow strictly this ideal type because the determining factors vary, for example one year there is more food, the other year less ...

Some people sometimes make calculate on the base of an exponential growth, stating for example how many billions descendents a female cat can have within ten years. In ecology it is important to know about mathematics, however it is also important to know when to use what formula. An unlimited growth in a limited system is not possible. Therefore also an economy based on permanent growth is bound to fail.