Evolution: Reptiles to Mammals
The evolutionary transition from synapsid reptiles to mammals.

Mechanisms for Change: Mutation
What mutations are, what they do, and what they can tell us.

Convergence or Introgression?
Could the mosaic of characteristics seen in fossil and extant hominids be evidence of past hybridization?

“Through a Glass, Darkly”
Dinosaurian hominids.


D. J. Scott

Mechanisms for Change:
Natural Selection

Free Your Inner Animal.
Copyright © 2016-2017 by Dustin Jon Scott
[Last Update: November 23rd, 2017]


Natural selection can be tested for against a null hypothesis defined by Hardy—Weinberg Equilibrium.

I.) What is Natural Selection?

Natural selection is the primary guiding hand for evolutionary change. This was the realization of Charles Darwin on his tour of the Galapagos Islands during his famouse voyage aboard HMS Beagle, although like most of the realizations that took place during "The Enlightenment", the origin of this idea lay within the philosophies of the ancient Greeks. A particularly eloquent description of natural selection occurs in On the Nature of Things by Lucretius (50 B.C.E.), which also includes as an example the artificial selection (a type of natural selection) that took place during the Pleistocene Mass Extinction and the advent of domestication in the Anthropocene:

For lapsing aeons change the nature of
The whole wide world, and all things needs must take
One status after other, nor aught persists
Forever like itself. All things depart;
Nature she changeth all, compelleth all
To transformation.
In suchwise, then, the lapsing aeons change
The nature of the whole wide world, and earth
Taketh one status after other. And what
She bore of old, she now can bear no longer,
And what she never bore, she can to-day.

In those days also the telluric world
Strove to beget the monsters that upsprung
With their astounding visages and limbs-
The Man-woman- a thing betwixt the twain,
Yet neither, and from either sex remote-
Some gruesome Boggles orphaned of the feet,
Some widowed of the hands, dumb Horrors too
Without a mouth, or blind Ones of no eye,
Or Bulks all shackled by their legs and arms
Cleaving unto the body fore and aft,
Thuswise, that never could they do or go,
Nor shun disaster, nor take the good they would.
And other prodigies and monsters earth
Was then begetting of this sort- in vain,
Since Nature banned with horror their increase,
And powerless were they to reach unto
The coveted flower of fair maturity,
Or to find aliment, or to intertwine
In works of Venus. For we see there must
Concur in life conditions manifold,
If life is ever by begetting life
To forge the generations one by one:
First, foods must be; and, next, a path whereby
The seeds of impregnation in the frame
May ooze, released from the members all;
Last, the possession of those instruments
Whereby the male with female can unite,
The one with other in mutual ravishments.

And in the ages after monsters died,
Perforce there perished many a stock, unable
By propagation to forge a progeny.
For whatsoever creatures thou beholdest
Breathing the breath of life, the same have been
Even from their earliest age preserved alive
By cunning, or by valour, or at least
By speed of foot or wing. And many a stock
Remaineth yet, because of use to man,
And so committed to man's guardianship.
Valour hath saved alive fierce lion-breeds
And many another terrorizing race,
Cunning the foxes, flight the antlered stags.
Light-sleeping dogs with faithful heart in breast,
However, and every kind begot from seed
Of beasts of draft, as, too, the woolly flocks
And horned cattle, all, my Memmius,
Have been committed to guardianship of men.
For anxiously they fled the savage beasts,
And peace they sought and their abundant foods,
Obtained with never labours of their own,
Which we secure to them as fit rewards
For their good service. But those beasts to whom
Nature has granted naught of these same things-
Beasts quite unfit by own free will to thrive
And vain for any service unto us
In thanks for which we should permit their kind
To feed and be in our protection safe-
Those, of a truth, were wont to be exposed,
Enshackled in the gruesome bonds of doom,
As prey and booty for the rest, until
Nature reduced that stock to utter death.

But Centaurs ne'er have been, nor can there be
Creatures of twofold stock and double frame,
Compact of members alien in kind,
Yet formed with equal function, equal force
In every bodily part- a fact thou mayst,
However dull thy wits, well learn from this:
Such hybrid creatures could not have been begot
And limbs of all beasts heterogeneous
Have been together knit; because, indeed,
The divers kinds of grasses and the grains
And the delightsome trees- which even now
Spring up abounding from within the earth-
Can still ne'er be begotten with their stems
Begrafted into one; but each sole thing
Proceeds according to its proper wont
And all conserve their own distinctions based
In Nature's fixed decree.
— On the Nature of Things; Lucretius, 50 BCE in Understanding Evolution: History, Theory, Evidence, and Implications by R. G. Price - March 5, 2006; Updated - May 2, 2006,
The Big Picture: From the Big Bang to the Meaning of Life - with Sean Carroll The Royal Institution. Youtube.
"The essential thing in metabolism is that the organism succeeds in freeing itself from the entropy it cannot help producing while alive. — Shroedinger, What is Life? in Searching for Life in the Outer Solar System - Europa, Titan, Enceladus (2/18/2016) CfA Colloquium Streamed live on Feb 18, 2016 Jonathan Lunine (Cornell)

I.) Types of Natural Selection

I.a.) Thermodynamic Selection

A very basic form of natural selection, Thermodynamic Selection, is likely responsible for stellar, galactic, universal, and possibly even multiversal evolution, as well as the growth of crystals and the propogation of fire. The form of natural selection we see in biological life, however, is far more dynamic and complex than the more simplistic Thermodynamic Selection.

Second Law of Thermodynamics says entropy always increases in a closed system. The consumption of usable energy transforms it into entropy (unusable energy, disorder, chaos).

This would have the consequence that systems and even parts of systems which use energy more efficiently will break down more slowly.

Over time, there would be an overall reduction in usable energy, although what systems or parts of systems remain will be highly efficient relative to the entropy of their surrounds.

In this way, physical and chemical reactions may seem to grow in efficiency and/or complexity and to propogate, even though there is a net increase in entropy for the larger system in which they occur.

Call this process Thermodynamic Selection.

This process makes itself most readily apparent to we mortals in the forms of fire, crystalization, and, of course, biological life.

Thermodynamic Selection also occurs on stellar, galactic, universal, and possibly even multiversal scales. In fact, stars, galaxies, and liveable universes are probably a result of Thermodynamic Selection.

If humans or some other intelligent species manage in the future to create a 2nd Big Bang, then this would help to explain the horrible specificity of the cosmological constant: A universe's laws of physics must allow for the creation of something within that universe, such as intelligent life, that can produce another universe, in order for universes to propogate themselves. This would make the cosmological constant the universe's DNA, and biological life the universe's RNA. Is the universe a bacterium? (metaphor: As Above, So Below) Some sort of self-replicating molecule propogating its way through a primordial sea of virtual universes that will never reproduce? (metaphor: And God [The Universe] walked upon the face of the watery chaos.) Might Dark Matter be some sort of horizontal gene transfer between "cells" of the multiverse?

Alternately, it could be that the sorts of furcating multiverses predicted by some many-worlds interpretations of quantum physics, in which a new universe is spawned per each possible outcome of a given quantum interraction, are the result of a selective process in which only universes that have laws of physics within certain accomodating parameters may reproduce. If protons, neutrons, electrons, and photons can't form, then a universe can't divide. In such a case, the cosmological constant would still be the universe's DNA but the RNA would be baryonic and leptonic matter.

Either way, the propogation of universes and the apparent specificity of the cosmological constant for any given universe are probably an example of Thermodynamic Selection.


I.a.) Lineage Selection

Systems which reproduce themselves "better" will beget longer lineages.

I.a.) Reproductive Selection

Systems which can reproduce more multitudinously will therefore begin to outnumber systems which reproduce themselves less multitudinously or singularly.

I.a.) Hereditary Selection

A form of reproductive selection in which an inherent quality of

I.a.) Environmental Selection

The efficiency of a thermodynamic system is relative to its environment. Systems may degrade more slowly in some environments than in others.

I.a.) Ecological Selection


I.a-2.) Sexual Selection


Works Cited

Eric BaptesteEmail author, Maureen A O'Malley, Robert G Beiko, Marc Ereshefsky, J Peter Gogarten, Laura Franklin-Hall, François-Joseph Lapointe, John Dupré, Tal Dagan, Yan Boucher and William Martin, “Prokaryotic evolution and the tree of life are two different things.” Biology Direct 2009 4:34 (Received: 16 July 2009; Accepted: 29 September 2009; Published: 29 September 2009) DOI: 10.1186/1745-6150-4-34
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