According to that model, however, a multicellular system can have a “collective memory”, and this does raise the suspicion that a more general memory could exist in living beings. More precisely it makes us think about a supracellular memory to which all body’s apparatuses contribute, a truly body’s memory.
Once the problem is formulated in these terms, it is not difficult to realize that such a memory does indeed exist, because the body plan has precisely the required features. The body plan is a set of characters that defines an animal phylum, and is surely a supracellular structure to which all apparatuses contribute. But the body plan is also a memory, because it is a structure that appears at an early stage of development, and, from that moment on, it remains in the organism for life, acting as a deposit of information for the three-dimensional pattern of organs and apparatuses.
The mathematical model, in conclusion, allows us to add a new biological property to the baüplane, an idea that can be expressed in this way: a body plan is a supracellular memory, or the body plan is the body’s memory. The proof that such addition is not only new but also useful, can come of course only from its power to solve real biological problems. One of which, as we will see, is precisely the problem of the Cambrian explosion.

A new model of the Cambrian explosion

The existence of organs and apparatuses in an animal implies the existence of a body plan, and therefore even the most primitive animals (with the possible exception of sponges) had body plans. It is unlikely, however, that the very first animals could already use their body plans as deposits of information, i.e. as supracellular memories. We have seen that the embryonic development of many characters can be realized with two different strategies, a continuous mechanism (more simple) and a discontinuous one (more complex), and the simplest mechanism is also the one that comes first in the history of life. In the case of behaviour, for example, a totally instinctive modality is not only more simple but also more primitive than a behaviour which is dependent on some form of learning.