The Genetic Book of the Dead — I. When the Past Gets Written into Life

An organism carries a history it never lived.

A bird has never experienced the environments in which its ancestors survived. A fish has never encountered the predators that shaped its lineage. Yet something of those encounters is present in the organisation of its body.

This is the puzzle at the heart of Dawkins' The Genetic Book of the Dead.

Evolution leaves traces.

But the trace is not necessarily a record in the ordinary sense. The genome does not contain a diary of ancestral experience. Instead, generations of differential survival have altered which genetic organisations persist.

The past has become biological structure.

A wing does not remember an ancestral flight.

An eye does not remember the light.

A camouflage pattern does not remember the predator.

Yet each embodies a history of environments in which particular organisations proved capable of persisting.

This gives evolution a peculiar form of memory.

It is not memory of the past.

It is memory through the present.

The organism has been shaped by conditions that are no longer there. Those conditions have left something behind that changes what the organism can do now.

And this is where the idea of a “book” becomes interesting.

A history book normally preserves information about something that happened.

An organism preserves something different.

It preserves the consequences of what happened.

Natural selection does not need to write a description of an environment into the genome. It changes the distribution of forms that survive within that environment. The surviving organisation is therefore evidence of a history without necessarily representing that history.

The present body can thus be read backwards.

Its structure tells us something about the conditions under which its ancestors persisted.

But there is an important asymmetry.

The organism is not looking backwards.

It is living forwards.

Its inherited organisation is being used in circumstances that may resemble, differ from, or depart radically from those that shaped it.

The past has become part of the organism's present possibility space.

And that raises a larger question.

How can a history become part of what a living thing is?

Perhaps the answer begins here:

The past survives evolution not by remaining past, but by becoming organisation.