The Genetic Book of the Dead — V. When the Past Changed What Could Survive

An organism inherits more than genes.

It inherits a set of possibilities.

Its inherited organisation determines what it can do, what it cannot do, and how it encounters its environment. When circumstances change, those inherited differences affect which variations can make a difference.

Selection therefore never starts from scratch.

Every generation begins with a history already incorporated into its organisation.

A variation appears within that organisation. Its consequences depend on the organism in which it appears. The same difference may matter greatly in one lineage and hardly at all in another.

History has begun to shape the conditions of its own continuation.

This makes evolution cumulative in a deeper sense.

The past does not simply produce the present.

The present, shaped by the past, determines which differences can matter to the future.

Inherited organisation → altered possibilities → differential consequences → further inherited organisation.

The genetic book of the dead is therefore not merely a record of what ancestors survived.

It is also a record of what their survival made possible for their descendants.

Each generation receives a world of possibilities already narrowed and opened by previous generations.

The dead are not directing evolution.

But their historical consequences remain active in the organisation of the living.

And once those consequences affect which new differences can persist, the past is no longer merely being carried forward.

It is helping to determine what kind of future can be inherited.

The Genetic Book of the Dead — IV. The Organism as Historical Layer

An organism is never only the result of its immediate circumstances.

Its organisation carries older histories.

A bird's wing reflects more than the environment in which the bird is flying now. Its structure is the outcome of inherited differences accumulated through generations of selection.

The same is true of the eye, the skeleton, the immune system, the nervous system.

Each is a present arrangement shaped by many past conditions.

Evolution therefore does not simply add adaptations one at a time.

It layers history.

A new variation arises within an organism already carrying an enormous inheritance. Selection acts upon that existing organisation. What survives becomes the starting point for further change.

The future inherits a past that has already been reorganised by earlier histories.

This makes evolution cumulative.

A lineage does not begin again with every generation.

It carries forward an organisation that has already been shaped by previous generations, and subsequent selection works upon that inherited organisation.

History becomes a condition for further history.

We can now see why the genetic “book” is so unlike an ordinary book.

A book has pages that can be read independently.

An organism has histories that interact.

A new adaptation may depend upon structures inherited from much older adaptations. A feature shaped for one function may later become the basis for another.

The present therefore contains not simply traces of the past, but possibilities created by earlier traces.

This is one reason evolution can produce such extraordinary complexity without foresight.

Natural selection does not need to know where a lineage is going.

It modifies what is already there.

The future works with the historical organisation it inherits.

And that means an organism is, in a profound sense, a record of what its lineage has been able to carry forward.

Not a perfect record.

Not a conscious record.

Not even necessarily a record of the environments themselves.

It is a record of which consequences of those environments became embodied in continuing lineages.

The organism is history made living.

And once history can accumulate in this way, a new question appears:

How much of an organism's present organisation can be understood as a solution to problems that no longer exist?

The Genetic Book of the Dead — III. When a Difference Entered the Lineage

A difference appears in an organism.

Most differences disappear with it.

A variation may affect an individual without ever becoming part of the future of its lineage. For evolutionary history to accumulate, something else is required.

The difference must be inherited.

This makes biological history peculiar.

An organism can acquire a scar during its lifetime, and the scar can change how that organism lives. But the scar normally does not become part of the organisation of its descendants.

A genetic difference can.

If it is passed on, the difference enters another timescale.

It can encounter selection again.

And again.

And again.

Now the consequences of a past difference can become part of the conditions under which future organisms develop.

The lineage has acquired a new possibility.

This is why evolution is not simply a record of individual adaptations. It is a process in which some differences become available to future generations while others disappear.

Inheritance turns difference into history.

Selection then acts upon that inherited variation, altering its distribution across generations.

The process can be represented simply:

variation → inheritance → differential persistence → altered lineage.

The important point is that the lineage does not need to remember the event that produced the variation.

It only needs to carry forward the difference.

Over time, many such differences accumulate.

The organisation of the present organism therefore reflects not one past event but a vast succession of events whose consequences survived long enough to become part of the lineage.

This gives evolutionary memory its extraordinary depth.

An organism can carry consequences of environments that disappeared millions of years ago.

But there is also a limitation.

The inherited organisation is not a faithful record of the past.

It is what remained after the past had acted upon variation.

The genome therefore tells us about history indirectly.

It preserves the consequences of differential persistence, not the experiences of ancestors themselves.

And this returns us to our larger question.

History becomes organisation when a difference produced by the past survives into a system's future and changes what that future can do.

In evolution, inheritance is the mechanism that allows the difference to cross the boundary between generations.

The dead do not speak.

But their differential persistence has altered the organisation of the living.

And the living carry that altered organisation forward.

The Genetic Book of the Dead — II. A Book Written Without a Writer

If the genome is a book of the dead, who wrote it?

No one did.

There was no author deciding what future generations needed to know. There was no ancestral organism recording its experiences for its descendants.

The book was written by survival.

An environment presents countless conditions and challenges. Organisms vary. Some variations leave their bearers better able to survive and reproduce under those conditions. Others do not persist as successfully.

Across generations, the distribution of variations changes.

Nothing needs to understand this process.

Yet the result is historical.

A population becomes different because of what happened to its ancestors.

This gives natural selection a peculiar capacity to preserve traces without preserving experiences.

Suppose an ancestral population repeatedly encountered a particular environmental condition. Individuals whose inherited organisation happened to cope better with that condition left more descendants. Over many generations, the resulting population can become well adapted to it.

The environment has disappeared.

Its consequences remain.

The genome therefore does not need to contain a description saying, this is what our ancestors encountered. Its organisation has been altered by the differential persistence of organisms that encountered it.

The “writing” is statistical.

It accumulates across generations.

And the reader is not the organism consciously consulting its genome. The organism simply develops and acts according to an organisation that already embodies part of its lineage's history.

This makes evolutionary memory very different from ordinary memory.

A remembered event says, in effect, this happened.

An evolved adaptation says something closer to organisations shaped by conditions like these have persisted.

The distinction is profound.

Evolution does not remember the past because the past was recorded.

It remembers the past because the past changed which forms remained available to the future.

That suggests a broader principle.

Whenever differential persistence allows past conditions to alter the organisation of what comes later, history has acquired a material form.

The genome is one extraordinary example.

But the deeper phenomenon is older than genes.

And that raises our next question:

Could history become organised before there was a genome to carry it?

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.