KERNEL: Evolution

KERNEL: Evolution
CONTENTS: Replicators (fecundity, fidelity, longevity), natural selection, genotype, phenotype, extended phenotype, ecosystems


The theory of evolution is somewhat tricky, as it has itself evolved over time. While there is broad scientific consensus, even such fundamentals as what should be considered the 'unit of selection' are hotly contested.

I personally favor the 'gene' (functionally defined in Richard Dawkins' The Selfish Gene) as the unit of selection, with the operative concept being 'that which replicates'. In that sense, genetics can be alluded to without going into detail. He defines 'general' natural selection as the differential survival of entities.

At any rate, it seems  as good a starting point for future scientists as any, from which they may draw their own conclusions.

I would personally like to include Dawkin's concept of the Extended Phenotype... the idea that genes encode not only the organism (phenotype), but also many alterations of the environment via the organism's behaviors ('extended' phenotype).

Formulation

As many more individuals are produced than can possibly survive, there must in every case be a struggle for existence, either one individual with another of the same species, or with the individuals of distinct species, or with the physical conditions of life.… 

Can it, then, be thought improbable, seeing that variations useful to man have undoubtedly occurred, that other variations useful in some way to each being in the great and complex battle of life, should sometimes occur in the course of thousands of generations?  

If such do occur, can we doubt (remembering that many more individuals are born than can possibly survive) that individuals having any advantage, however slight, over others, would have the best chance of surviving and of procreating their kind?  

On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed.  

This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection.

-- From The Origin of Species by Charles Darwin


Reformulation

1. Traits: Organisms pass (genetic) traits on to their offspring (sometimes imperfectly).
2. Variation: There is trait/organism variation in every population.
3. Offspring: Organisms produce more offspring than can survive.
4. Competition: Organisms compete for limited resources (according to their traits).
5. Natural Selection: Those organisms embodying more beneficial (adaptive) traits are more likely to survive and reproduce (differential survival of entities).

To which I'd add:

1. Speciation: the Origin of Species.
2. The Extended Phenotype (Dawkins): Genotype > Phenotype > Environment > Genotype
3. You Are Here: Note on where one fits in the Grand Scheme of Things

Rendition

1. The First Ancestor

In the deeps of time
In the seethe of chaos

In the broth of possibility
The first ancestor chanced to be
Matter twined unto itself

Itself a pattern for another

The first replicator

That which copies itself

The ancestor of all life

One became two

Two became four

Four became many

Many became all

Spread high and low

Deep and wide

Filling all the world
One great family

2. Script

Script is within all living entities

Too small for eyes to see

Encoded with instructions

Script written by the world

As we shall see

According to script

Bodies and their parts

Are built to plan

According to script

Bodies in their workings

Are regulated in function

According to script

Bodies in their features

are constrained in possibility

According to script

Bodies in their behaviors

Are given tendencies

These expressions we call traits

Script is copied from parents to offspring

Cut in sex and shuffled

Half from each

According to rules passed down

Within the script itself

Script may be copied awry

And the script is changed

Script may be damaged

And the script is changed

Script may be rewritten

And the script is changed

Where the script is changed

Are bodies changed

We call these changes mutation

Mutation in script

Mutation in form

Mutation in function

Mutation in behavior

Often is change injurious

Sometimes is change indifferent

Seldom is change advantageous

Advantage is rare

Advantage is precious

Advantage is preserved

Advantage is compounded

Refined in the long course of generations

From the first script

Of the first ancestor

Is the script rewritten

Adaptation writ quick

Mutation writ slow

Script may lie long out of reach

Yet knowing script is

May guide your knowing

3. The World and Script

More are brought forth

Than the world can bear

Not all who are born survive

Not all who survive may breed

Not all who breed give birth

Nor bring their young to breed again

Passing script from parent to offspring

According to what is written

In this circle of life

Do a few go forward

Of the many who live

Without intent

Without malice

Without mercy

The world weighs against all

Life competes for life

Each with its kind

Each with other kinds

Each vies with the world

Each vies for limited resources

Each exposed to hard chance

Each according to its script

Through quick and shuffling adaptions of script

Through slow perfection of mutations of script

Do those entities endowed with more advantage prosper

Do those entities burdened with less advantage wither

Thus unknowing and blind

Does the world naturally select

Which may prosper

And which do not

4. Speciation

Whence come the many kinds?

Each kind is like unto a branch of a great tree

When one kind is divided for a while

Some of their number here

Some of their number there

Separated

By land or sea

By diet or habit

Each grows in its surrounds

Each shaped by its surrounds

One isolate from the other

Over many generations

Scripts diverge according to need

Bodies diverge according to script

Each adapting to their divergent surrounds

Each accumulating small changes in script

Too much change

Fertile offspring fail

A branch is parted

New branches form

Kinds from kind are sprung

In the long years of deep time

So many branches

So many kinds

5. Evolution

Script

Bodies with traits

Shuffled by sex

Winnowed by the world

Culled by what is

Culled by what is not

Fitting form to function

Mindlessly suppressing

That which is less fit

To its place in the world

What works goes forward

Adaptation proceeds

One generation to the next

Tending fit form to function

Within the ever changing world

Bodies build bodies 

According to script

Bodies compete

According to traits

Winnowed or spread

According to success

Of bodies they build

Body and trait

Each shaped by the world

Each shapes the world in turn

Differential reproduction of bodies

Differential propagation of traits

Compounds success

Gives rise to kinds

Furthers the adaptive

Supresses the rest

The world is the blind selector

Indifferently differentiating

6. Script and the World

As the world shapes script

As script builds bodies

As script enables behavior

So script reorders the world

Bodies and behaviors change the world

The changed world demands adaptation

Adaptation changes the world in new ways

Look around you

Observe teeming life

Observe its influence on the surrounds

Observe the balance

Observe what disrupts the balance

Observe how balance reestablishes

In these you see script made manifest

In these you see the world at work

Work without effort

Work without intent

7.  You

You are a living entity

You are of the family of life

You are not special

You are special

You and yours are not among the many

That have yet gone extinct

Reached the end of their run

Of well adapted fortune

Each of your ancestors

Survived long enough to reproduce

Reaching back to the first

You are a survivor

In that very long line

Tho life may appear struggle
The trend is adaptive

For those who adapt

This world a paradise

8. If you would know

Look to strategy of individuals

Look to survival of individuals

Look to replication of individuals

Look to reproduction of individuals

Look to relatedness of individuals

Look to relationships between individuals

Look to competition between individuals

Look to cooperation between individuals

Look to dependencies between individuals

Look to dependencies among individuals

Look to survival of offspring

Look to distinction of kinds

Look deep within each being

Look deep within the world too small for eyes

Look to those entities which replicate

Look to flow of information
Look to flow of energy
Look to flow of resources
Look to flow of the world

Remember this

The world is the blind selector

Indifferently differentiating