Introduction to a proposed book
that was abandoned as
redundant
by Ken Wear, posted 11/04
How it all began is a matter of conjecture. Whether we will ever know with a
certainty seems highly unlikely.
There are two forms of existence known to science: mass and energy. Gravity is
just there and time simply passes. Mass is ‘stuff;’ it occupies volume and, if acted
on by gravity, has weight; energy has no mass but, according to the theory of
relativity, has an equivalence to mass. Some would argue that there is in addition a
"something" that can be called "spirit;" it has no mass, broadcasts no energy, is not
affected by gravity, may be as pervasive as time, and gives the living a quality not
possessed by the non-living.
What is beyond Earth (and its moon) is not yet man’s to touch although we have
sent instruments to explore nearby bodies. We observe almost entirely by
captured energy -- light emitted by celestial objects, reflected star(sun)light from
planets plus other forms of electromagnetic energy -- emanating from what we
assume is mass. We use our mathematics to calculate how it is all held together
by gravity and then extend our interpretations, using laboratory observations of known
phenomena, to measurements of intercepted energy; we then speculate on its meaning.
Time simply passes and we, the living, are animated.
I suppose man has, since the origin of intelligence, looked beyond his reach, out to
the horizon, up to the heavens, curious about what his fingers would touch could he
reach that far. Looking at the horizon he sees objects and shapes; he can go there
and examine the objects he sees in the distance, but the horizon extends onward and
is, no matter how he approaches it, forever beyond his reach. Looking upward the
eye beholds, but no matter how high he climbs, he cannot reach; he can only wonder.
By grouping those points of light he may imagine outlines that suggest familiar things,
giving rise to astrology and its explanations.
It seems unrealistic to suppose that all of the matter in our Universe has always
existed, that it had no beginning. Granted that the sheer magnitude of the mass
and the volume it occupies defy the imagination, our species has been successful
(apparently) in observing and quantifying much of our neighborhood in the totality
of it all. Thus far our most powerful instruments have found no edge and, if our
mathematics be trusted, our observations have detected only a small fraction of
what total mass must surely occupy the volume we have been able to observe and
study. But here it is; we are a part of it and we have a driving compulsion to
understand why and how.
We make one audacious assumption: that the same physical and chemical processes
apply throughout the Universe. There may be differences of scale, or subtleties, so
that we do not understand; there may be things we don’t even suspect; but, rightly
understood, the same laws apply equally everywhere without exception. Until
we have reason to think otherwise, that assumption prevails and governs our
interpretations.
Time is a nebulous concept. We each have a sense of the passage of time in that
our minds embrace thoughts one following another in a sequence. We have
learned to measure the passage of time as sub-divisions of the daily rotation of
our planet or its annual orbit around our Sun, and we have learned to incorporate
time in our mathematics. But I question that the passage of time itself is dependent
on events that can be observed and measured; time simply passes inexorably
moment by moment as it has forever without beginning -- even before the
Universe contained any matter whatever.
Did that initial emptiness possess intelligence? That is the quandary of pre-existing
deity. Whatever your conviction about deity, let us explore what our science tells us.
Added note Nov. '05
I interpret science as observation, measurement and analysis of specific events.
It includes conjectures that have often been precursors of further exploration,
measurement and analysis. But it is always and evermore a study of what effects
grow from a specific describable cause. Taken in this light the Big Bang is the
most colossal denial of science I can imagine; yet scientists have adopted it and
devised mathematics to defend it. We are presented with the idea that, from
nothing and without cause, there proceeded an eruption so powerful and
extensive that the universe entire came from it.
To make my presentation more compatible with conventional science, I have moved
description of my speculations to the end of this essay.
Through our reception of energy we see this unending turmoil as a variety of
concentrations of mass: extensive clouds of dust and particles, coalescing
clouds in the process of generating new stars, stars during their life and in their death
throes, explosions that disperse mass and thus take part in generating new clouds.
Our science is beginning to discover and apply mathematics that allows understanding
of part of what we see. It is indeed an immense caldron in which our view is strongly
influenced by our line of sight and the orientation of the clouds and star systems with
respect to our line of sight. And it is thus far perplexing.
Whatever the particles from those eruptions of nothingness, and how they may have
combined, the most numerous particle resulting from condensation of primordial matter
was the hydrogen atom. A sun the size of ours, after converting most of its hydrogen into
helium in the fusion process, is expected to contract until the heat of compression ignites
helium fusion; further depletion, contraction and temperature increase should produce
heavier elements up to carbon and oxygen. A larger star may through successive
contractions, each contraction igniting a heavier element as fuel, produce elements as
heavy as iron. Our theory says a star as large as eight solar masses (Our Sun is one
solar mass) ends its life in a supernova, a colossal explosion of extreme brilliance,
blowing away most of its matter. But that matter isn’t lost; it is dispersed into space to
become available to take part in forming new concentrations of gases and particles from
which new stars can emerge.
The age of the Universe -- elapsed time since the Big Bang (or the most recent Bang) -- is
taken as perhaps 15 billion years. The age of our Sun is taken as perhaps 5 billion years,
roughly the same as the estimated age of Earth. Likely during those first 10 billion years
many local events, including supernovas, produced ever heavier elements so the nebula
from which our solar system formed included heavy elements up to at least uranium, the
heaviest element found in Earth’s crust. (In the reckonings of how many suns are orbited
by planets capable of supporting life, it is evident that such a sun would have formed
from remnants of a supernova; otherwise its planets could not have included the heavier
elements that are necessary to life and to building a world. This consideration alone
limits the number of stars in our galaxy that may claim planets that host life.)
Somehow the mass was set to spinning, doubtless due to spin of the vastly larger mass
of our galaxy, of which our nebula was an infinitesimal part; and that spin resulted in a
disc-shaped nebula, doubtless much thicker at the center than at the outer rim. We can
only guess at the temperature distribution within regions of this disc, although reason tells
us that the thicker central portion was hotter than matter radially farther out, and a line
drawn laterally through the disc would show higher temperatures at the disc’s center.
Within this disc gravity and centrifugal forces led to differentiation so the heavier
elements tended to concentrate toward the center of rotation.
Whatever explanations are finally reached about formation of the solar system, there are
irregularities that must be explained, such as lack of completion of concentration of the
heavier elements in the center, departure of planetary ecliptic planes from radial
alignment, retrograde planetary spins, formation of smaller bodies orbiting their hosts,
. . .
Some think the planets were cast off by a forming sun; others think our planet and its
siblings resulted from the gravitational pull of a celestial visitor passing near the Sun and
stripping off chunks of matter; still others think an accretion disc containing all the matter
of the solar system separated into rings. What led to separation of the disc into rings from
which the planets could form by accretion is a matter of debate. I take the theory of
disc formation and subsequent accretion of the Sun and planets as the more likely since
there must be a balance between gravity and centrifugal force if stable orbits are to be
produced. And the accretion theory leaves little question that the planets formed from the
same source material as the Sun and likely resulted as an integral part of the process that
produced the Sun.
Formation of Earth was a coagulation, at first small, of particles and debris in our ring of
the disc. As the ring was drawn together by gravity there resulted larger chunks, then
asteroids; finally, with a growing sphere whose gravitational attraction became dominant,
the disc collapsed although there was yet much debris to produce intense (and
diminishing) bombardment for hundreds of millions of years. Somewhere along the way
the Sun ignited. Whether Earth was molten due to the compression that eventually ignited
the Sun, or whether its temperature was raised by the energies of collision as it accreted
by meteorite or asteroid or planetesimal strikes, it was doubtless molten all the way from
core to surface, and gravity-induced differentiation led to concentration of iron toward
the center.
Except for the products of radioactive decay (and relatively minor contributions from
meteorites), the accretion disc contained all elements present in our Earth. While molten
the heavier elements tended to sink toward the center, but solidification followed soon
enough that Earth’s crust contained significant quantities of the heavy elements,
including uranium.
Perhaps we should ask the question dealing with the age of Earth: At what point in its
accretion should we say its origin was completed? Radiometric dating of some of the
oldest meteorites known place the age of the meteorites at 4.7 billion years, but the age
of a meteorite does not reveal when it struck Earth; accretion must have been nearly
complete when it struck since it was not overlaid by later-arriving accreting materials.
And there must have been a crust of thickness sufficient to absorb the blow and
support the meteorite, as well as cool enough it did not re-melt, thus allowing the
meteorite to retain its identity.
(The accumulation of matter from space has not ended. Every year meteors and
meteorites add some 200,000 tons of matter, scattered randomly. Because of estimated
velocities of these fragments, it is felt they originate within the solar system and are not
from deeper regions of space. Possibly including remnants of our primordial disc? And,
from time to time Earth has been struck by a chunk large enough to disrupt processes at
the surface. In most cases frictional heating in the atmosphere vaporizes a meteorite; it is
a rare one that is large enough to reach the ground with an internal temperature modest
enough that whatever life the meteorite supported was not destroyed during transit
through Earth’s atmosphere.)
Radiation of energy is known to follow a fourth power law, so, as temperature drops, heat
exchanges by radiation diminish rapidly. Within that ring, laterally out toward the edge,
particles cooled toward the prevailing temperature of outer space. But toward the center
they remained quite hot. Matter at various places joined and congealed into various sized
chunks at various temperatures. So, as our sphere formed it was struck by particles large
and small, hot and cold, from nearby and great distances, some with great impact energy.
We have the surface of our moon as a model of surface deformation due to meteorite
strikes; they are sporadic; they result in cratering and (with enough impact energy)
remelting and flow. With slow conduction of heat along the surface, because of extent,
temperature differences developed so some regions solidified while others remained
molten. We can appreciate the early surface deformations leading to a crust of uneven
elevation.
Observation of other newly-formed suns suggests that ignition is followed by an
outward wind that divests the sun of all gases not tightly bound gravitationally. Thus
what remained of our uncollapsed disc was purged of its lighter gases, hydrogen and
helium, and Earth was subjected to a solar wind that swept away gases not gravitationally
bound or trapped in the Van Allen belts. Therefore what atmosphere Earth possesses
today had, after the Sun's ignition and initial solar wind, escaped from Earth's interior,
likely consisting mostly of carbon dioxide. And lighter gases, including hydrogen from
dissociated water, were so energetic by virtue of their temperature as to escape Earth’s
gravitational pull.
Distribution of elements within this sphere was obviously uneven although not enough to
cause a discernible wobble in Earth’s daily rotation. Gravity produced a sphere of this
molten blob and the centrifugal force of rotation produced an equatorial bulge and polar
flattening. While gravitational differentiation within this melt concentrated the heavier
elements toward the core, this process was slowed and interrupted by cooling and
formation of a crust. With formation of a crust, the contraction that accompanied
further cooling compressed a relatively incompressible interior so that the pressure led to
volcanic activity. An atmosphere of unknown composition formed.
Eventually water vapor was present. With enough krinkled crust, an atmosphere and
water, the story constructed by geologists, paleontologists, paleobotanists and others
can begin.
There are yet today at Earth's surface pockets of radioactive particles whose
decay produces heat, so evidently there was initially enough radioactive decay that
it contributed to Earth’s temperature. We can only speculate on the influence of
radioactivity on Earth's thermal history, and we have no notion how much
radioactive material exists in Earth's core.
We can’t know how long it took for Earth to cool enough to allow the initial molecular
combinations that became the precursors of life, although the surface must have been
well below the steam point so that there could have been rain and erosion (with its
sludge) and significant bodies of water.
Earth’s core is molten, enriched in iron, and in motion (presumably something akin to
massive rivers or perhaps like the Gulf Stream that flows like a river in the ocean).
There is a magnetic field (presumably produced by this iron in motion) so that Earth
behaves like a pole magnet with north and south at opposite ends. Over time the
direction of that magnetic field has changed, even reversed, and it is difficult to imagine
the kinds and magnitude of force that could so alter the flow of those rivers of iron in
Earth’s core (unless it was uneven or irregular cooling so that obstructions to flow
built up or shifted -- we certainly wouldn’t think the underside of the crust is smooth).
The charged particles in the solar wind, mostly protons (hydrogen nuclei) and electrons
with some helium, travelling at 350-800 kilometers per second (and peaking at 2200
during solar flares) react with Earth's magnetic field to produce the Van Allen belts so
Earth’s atmosphere is shielded from direct bombardment by the wind. Perhaps Earth’s
early atmosphere of hydrogen was partially protected from the solar wind by the Van
Allen belts although Earth’s temperature likely heated hydrogen enough that it escaped
at low thermal velocities in spite of this shielding. (One result of the interaction
between the solar wind and the inner Van Allen belt is the aurora seen at times in
northern skies.)
What impact the solar wind? Presently the Van Allen belts leave only the poles
exposed. It has been estimated that reversal in direction of Earth's magnetic field has
occurred about four times each million years (and is now long overdue).With changing
direction, and varying magnetic field strength, exposure at Earth's surface to the
continued bombardment by particles in the solar wind must surely vary -- has varied
many times -- (with effects not yet correlated with fossils).
Both the sun and moon attract oceanic water to produce tides, with lesser tides when their
gravitational attractions are in opposition and higher tides when they are additive.
Because the moon is very slowly orbiting farther and farther away from Earth, the moon
was at one time much closer than it is today. So in the earlier days the tides had a
ferocity greatly exceeding that of today.
Temperature at Earth’s surface is subject to a number of influences and not only varies
greatly over its surface at any one time but has varied greatly with time in any one
location. The radiant energy emanating from the Sun is essentially constant, and Earth’s
distance from the Sun is essentially constant, so the radiant energy per square foot (or
square meter) is essentially constant at the surface of the great sphere having the Sun at
its center and Earth in its shell. But a patch of surface of our globe may be inclined to
the incoming energy so the energy is spread over a larger area and results in less solar
heating per unit of area; thus the poles are colder than the equator. And the tilt of Earth’s
axis of rotation to the orbital plane produces seasons as Earth orbits the Sun. Moreover,
rotation on its axis causes alternating heating (by day) and cooling (by night) of any patch
of surface.
We can reflect on the consistent and gradual changes in Earth’s surface. The globe likely
was never smooth, but meteorites and larger fragments caused varying but modest
elevations in the early days of solid crust, and volcanic activity added to the unevenness
of the surface. By the time Earth cooled enough to allow liquid
water to settle on the surface, there were basins to collect it. With time, as Earth grew
and cooled, the amount of dry land increased due to both accretion and volcanic activity,
the depth of the atmosphere increased, the depth of waters increased and the depth of the
crust increased. Over geologic time it was a slow progression of a very volatile picture.
Solar radiation includes the spectrum from far infrared through ultraviolet and X-ray
while radiation from the ground is much lower temperature (longer wave length
infrared). The gases carbon dioxide and methane (a by-product of life) allow
unimpeded passage of near ultraviolet, visible and near infrared energies but reflect
most infrared (except for several narrow windows). Taking the early composition
of Earth’s atmosphere as mostly carbon dioxide,
Earth intercepted vast quantities of solar energy but could not lose energy well because,
at the longer wavelengths, heat from Earth’s surface was reflected back to the ground.
Moreover, dust in the atmosphere, as from a volcanic eruption or a meteorite strike or a
massive forest fire, may increase reflection of energy from both sources. Thus Earth’s
surface temperature is strongly influenced by its atmosphere’s content; one consequence
is that Earth has been subjected to temperature extremes that have produced a number of
glacial epochs during which much of its water has been locked up in glaciers. Such
reduction in the quantity of surface water has caused sea levels to drop, exposing
immense areas to direct sunlight and weather effects. And the ice retreated from the last
glacial period only a few (about twelve) thousand years ago.
Influencing life on the surface in two ways is the quantity of atmospheric oxygen. Of
course, oxygen is necessary to animal life as we know it. Further, oxygen in the upper
atmosphere produces an ozone shield that absorbs shorter (more energetic and therefore
more harmful) ultraviolet radiation to protect life on the surface. Because of its strong
chemical affinity, oxygen was initially likely all bound up in the solid aggregates, so
atmospheric oxygen must have been liberated by life processes (plant life) that absorb
carbon dioxide and release oxygen.
Atmospheric composition is obviously influenced by the processes at (and underneath) the
surface and is mostly a balance between production and consumption; composition has
certainly not been constant and may have varied widely to as much as 30% oxygen. It is
estimated it took 4 billion years for the oxygen content to reach 7%, from which it
eventually settled at today’s 21% oxygen, 78% nitrogen and other gases including water
vapor.
What is now North America was apparently, at 3.8 billion years ago (bya), at least half as
large as it is today. All of the exposed land may have been concentrated in the super-
continent of Pangea, or it may have been in two land masses, Gondwanaland in the south
and Laurasia in the north. Or Pangea may have split and been reunited, but as early as
1.0 bya there were five independent continents. By another reckoning the one continent
of Pangea existed at 250 million years ago (mya); it had split into Laurasia and
Gondwanaland by 200 mya; at 135 mya Gondwanaland split between Africa and South
America so the South Atlantic was opened; and at 60 mya the North Atlantic split into
Europe and North America. Mountain building, rifting and opening and closing of the
oceans have all played a part in the history of Earth’s flora and fauna.
In our times we have experienced storms, some very devastating in their effect.
Frequency and fury seem to increase where the Sun’s energy is intercepted in greater
quantities. It is almost terrifying to reflect on the severity of storms in those early millions
of years of higher temperatures. We have also experienced floods; no doubt floods also
figured prominently in Earth’s past, some minor and some devastating almost beyond
belief. And during the last million years glaciers have advanced and retreated seven times.
The modern view of Earth is a solid core at perhaps 4500oC but cooling to
3700oC) at the core’s outer limit, bounded by a melt from 1000oC
to 2500oC; the solid mantle resting on this melt supports the tectonic plates
on which ride our continents. In deep mines there is a measured rise in temperature of
2-3oC for each 100 meters (33-50oC per mile), but scientists
have been unsuccessful in drilling and bringing up cores from great depths. With some
4000 miles from surface to center and perhaps several hundred miles depth of crust,
Earth still retains immense quantities of heat energy.
At the present balance of Earth’s internal temperatures, the surface rides on huge
subterranean tectonic plates that are moving slowly but inexorably. Continents are
changing in relative position. Earth’s dry land was apparently joined together in its early
days, but separated through motion of the tectonic plates and then rejoined before
separating toward their present positions. Lines along which there is volcanic activity
coincide with edges of adjacent plates where they are being pushed together or pulled
apart by underlying forces. And new surface ground is being created by solids vented
from volcanoes.
Earth’s surface features have been influenced as one plate forces another to rise (or sink),
by volcanic activity, by weathering and erosion, by build-up layer by layer of sediments
and their subsequent torture by forces from within Earth. The fossil record has, in fact,
been found in these layers, and correlations of content of the layers has enabled
construction of much of our knowledge of past flora and fauna as well as the epochs
during which they populated Earth. These same correlations have also been used in
dating newly uncovered strata so that dating strata and identifying fossil finds have
reinforced each other.
Fossil finds have been unearthed in earth-moving operations involved in developments
of highways, high-rise buildings and shopping centers, but these are relatively trivial
motions of Earth’s surface. For the most part fossil finds occur in sedimentary rock
that has been exposed in mountain ranges, or along rivers where erosion has worn
down a face of the rock, or in erosion gorges with strata tilted due to earth movement
or mountain building.
We can perhaps appreciate the value of sedimentary rocks in studying life -- plant and
animal -- in pre-history. Sediments containing the newly-living are laid down under
water, buried, compressed into rock, and in the fullness of time because of the forces
of nature brought to the surface again. In studying the content of layer after layer a time
sequence of organisms can be constructed. Through various techniques a time line has
been established and comparisons with the results of study of other strata located
elsewhere in the world has allowed the gradual elucidation of life forms -- and their time
sequence -- long disappeared.
Before there was enough surface water to create erosion and sediments of erosion
products -- well, we just have to look for other kinds of clues. Radioactive decay.
Meteorites in those rare locations we feel have not been disturbed since the early crust
formed. (Origin and dating and analyses of meteorites is a fascinating study in its own
right, but we wish not to be distracted from our story of Earth’s development.) We
must appreciate the very special conditions required for preservation of fossils and the
length of time they must have been preserved despite the on-going saga of weather,
glaciations, volcanism and earthquakes, continual overlaying by deposits from space.
It is in the sediments we have found clues, and it is surprising that the fossil record has
been developed as completely as it has.
We can only speculate on the interplay of chemical reactions, erosion and creation of
sediments as that early crust formed and during the continued cooling of our glob of
matter. But we can know of a certainty that it was hot and very slowly cooling.
To give some idea of the simplicity (or complexity) of the simplest organisms, consider
that a molecule of salt (sodium chloride) measures some 0.3 millimicrons in diameter,
while the smallest viruses susceptible to examination are some 20 millimicrons in
diameter. They are rod-shaped and consist of nucleic acid surrounded by a protein
sheath. Evidently such a small virus consists of hundreds of molecules (thousands of
atoms arranged in specific patterns). In the microscopic world of today we know there
are viruses that invade bacteria; there may be yet smaller units that invade viruses.
Statistically, the odds against such a chance arrangement of molecules, in the simplest
life-possessing units we know, are astronomical, so, in the search for the steps leading
to the generation of life, we must look for a group of intermediate hunks of matter yet
simpler than the smallest virus known.
We can accept with no uncertainty that there were intermediate stages between a very hot
Earth, with its slurry of chemicals, to the simplest molecular combinations that bridged
the gap from non-living and living.
In our chemistry of today we see organic compounds as both necessary to life and
the product of life. It is a circle; life is necessary to the generation of life. But early
Earth was entirely inorganic; it was devoid of organic compounds.
There has to be a point at which life is recognized as having taken hold. In searching for
the origination of life, we must declare how we perceive a definition of life. We take the
defining characteristics of life to be metabolism (receiving nourishment and divesting
wastes) and reproduction (producing more of like kind). The simplest form of
reproduction as we view it today is division of an organism by splitting of its
nucleus with each portion taking along a portion of the sheath and other structures.
And we note that the nature of Nature seems to be for each organism to multiply either
to the extent of available nourishment or until some other organism uses it for food in
its own life processes.
I note that life has been discovered in what we had earlier felt were very unlikely places
such as volcanic vents at extreme ocean depths -- extreme pressure and temperature --
which suggests that life will arise wherever there is energy and nourishment. Chemists
suspect that ammonia, methane and water vapor in the early atmosphere (assuming
Earth’s atmosphere was then similar to that of Jupiter today) may have combined,
under the influence of ultraviolet radiation, or the energy of lightning, to form amino
acids. Amino acids form chains to make protein, which is the structural stuff of life.
Amino acids and other chemicals collected together in pools to make an organic soup
from which the very complex molecules of life may have built up from simpler
precursors. Or clays at hydrothermal springs on the sea floor may have catalyzed
assembly of RNA molecules.
During the past few decades chemists have demonstrated the simplicity of generation
of amino acids, and they have, under carefully controlled conditions, produced chains
of acids to form simple proteins. And sufficiently long chains spontaneously form
structures. What is the smallest, simplest combination of molecules capable of
self-replication? My guess is that it will be a surprise if and when man finally divines
a sequence of chemical combinations and reactions that can produce something
capable of self-replication -- life. Weather and surface deformations before that time
are irrelevant to the story of life. I am sure there was considerable elapsed time,
possibly hundreds of millions of years, before this new life grew in complexity
sufficient to leave traces that have been or can be recognized.
To make my presentation more compatible with conventional science, I have moved
description of my speculations to the end of this essay.
Let us marvel at the genesis of life: Whatever the primordial particles may be, they
coalesced into electrons, protons and neutrons, which combine in various patterns to
form atoms of the 92 naturally occurring elements known to us. In turn atoms combine
in various ways to form molecules of substances such as water, lye and carbon dioxide.
The next level of organization is, in chemistry, compounds such as soap and steel, and,
in living organisms, cells. While science has learned how to make simple proteins,
how to devise the simplest cells is yet well beyond speculation.
Let's examine relative sizes using bacteria as a base line, noting that our most powerful
microscopes are limited to modestly-sized molecules.
The simplest cells are enormously complex, including a surrounding membrane and whole
collections of specialized structures within. The simpler cells do not have nuclei although
multi-cellular organisms require cells with nuclei and other structures; all cells have in
common DNA strands enclosed in chromosomes of various lengths, each chromosome
housing its peculiar strand. DNA consists of sequences of only four protein molecules
although a strand may be millions of molecules long; yet DNA contains the distinct
blueprint for each species of the millions of plant and animal species inhabiting Earth.
And the most complex organism, man, is initiated from a single cell.
What portions of those DNA strands comprise which gene that determines some structure
and what induces various genes to turn on and off in the proper sequence are mysteries
yet to be solved. (Some few genes have been identified, and even replaced with healthier
genes.) But discovery of that double helix was only the beginning of unravelling the
mysteries Nature solved eons ago.
The earliest suspected evidence of life is algal -- plant life. Evidently a primitive
chlorophyll formed and may have taken part in or been captured by the sheaths. And the
simplest cells that have been identified are so-called prokaryotic bacteria, which have DNA
enclosed in a membrane but have little internal structure. I have no idea whatsoever what
proteins may arise spontaneously in a petri dish laced with the correct chemicals, but I
have no doubt some are known. Those hundreds of millions of years before the first life
has been detected consist of how many bacterial life-times? Certainly enough for zillions
of combinations to form. And it only required one event that could repeat itself for life
to be on its way. My intuitive feeling is that it was inevitable that life should start, likely
under water where the protective ozone shield was unnecessary.
Composition of Earth's atmosphere is both cause and consequence of events at or near
the surface. Obviously, water vapor. And carbon dioxide for consumption by plants,
and oxygen for consumption by animals. Atmospheric oxygen was a later development
so we assume plant life (with single celled organisms arising first) preceded animals.
We can after a fashion place in sequence developments in life forms along the path to
the appearance of mammals. The primacy of water is evident; in fact the oxygen we
breathe is dissolved in the water in our lungs in order to penetrate the blood vessels
to cleanse our blood. If early creatures required oxygen for their life cycle, then
oxygen had to be available either as gas in the atmosphere or dissolved in the water
from some ore -- and recall the slow increase in atmospheric oxygen.
For the theologically-minded, we must ask at what point the deity was sufficiently
organized to begin bringing some influence to bear on developments. Considering the
relative lateness of the origin of our Sun, it seems more reasonable to assume the origin
of deity preceded the origin of the Sun. It is entirely possible that life did not
originate on Earth but arrived here by way of interstellar visitors. Perhaps a meteorite
was ejected by a supernova in some distant nebula and over the millennia journeyed
to Earth. (Let us ignore both the temperature associated with the energy released by the
supernova and the temperature reached in our atmosphere, which would have destroyed
most vestiges of life). Be that as it may, that gives us no excuse to cease our search for
knowledge of how that life may have come about. (I would guess that the deity was
constrained to work within the physical characteristics of the materials at His disposal.
As opposed to inventing characteristics as He went along.)
We shall shortly be concerned for fossils. Perhaps we should recognize that biologists
have divided all known life forms into categories (kingdoms) -- with some remaining
controversy about kingdoms and assigning simpler life forms to their appropriate kingdoms.
(Initially biologists divided life into two kingdoms: plant and animal. That proved
inadequate so it was proposed to divide life into five kingdoms -- above. Other biologists
felt this also inadequate and proposed dividing life into eight kingdoms.)
The kingdoms of life forms are divided into phyla (or groupings) following anatomical
characteristics of each life form. Botany is the study of plants, of which there are six
major groups. Bacteriology is the study of bacteria. Zoology is the study of animals,
of which there are recognized today some 25 major groups or phyla.
Evidently, our best hope for finding fossils lies with plants and animals; it is highly
unlikely that smaller organisms will have left physical bodies or body parts that we
will be able to detect. Both size and lack of solid structures hinder us although --
speaking of size -- there has been effort to study pollen found in fossilized animal
spoor.
It would be interesting to correlate changing geographical characteristics of the globe
(including tectonics), changing weather, rising and falling of the oceans as glaciers grow
and retreat in eras of warmth and cold, the gradual increase in complexity of life forms
influenced by these changes, and the actual life forms and fossils arising from these
variables. I leave this for the professionals.
The Archean eon persisted for 1.5 billion years or until 2.5 bya. There is evidence
of oceans and the first evidence that might be construed as life at 3.8 bya. The oldest
suggestions of fossils was at 3.5 bya. The thickness of Earth's crust is estimated at
70 miles.
The Proterozoic eon persisted for nearly 2.0 billion years, or until 0.57 bya (570
mya). The oldest algal reefs are placed at 2.0 bya and the first green algae at 1.0 bya.
Before about 2.3 bya, when oxygen in the atmosphere began to increase, there were
only single-celled organisms; the first eukaryotes emerged about then. Mitochondria
in the eukaryotes emerged between 2.3 and 1.8 bya, not long after the rise in oxygen
concentration, and may have been the catalyst for increase in the number of cell
types. The split between plants and animals has been estimated at 1.6 bya. Plastids,
the plant component that enables them to produce oxygen by photosynthesis,
originated about 1.5 bya. Eukaryotes with up to ten cell types emerged by 1.5 bya;
with up to 50 cell types by 1.0 bya. (Plants and animals today have more than 100
cell types.) During the last 30 million years of the Proterozoic eon (the Vendian era)
there arose the oldest soft-bodied animals (jellyfish, worms, anthropod-like forms).
There had been massive glaciation around 950-900 mya, again around 750 mya,
and the Proterozoic eon apprently ended with massive glaciation at 600 mya.
Taken together, the Hadean, Archean and Proterozoic are the Precambrian eon.
The Phanerozoic eon extends from the Cambrian onward to today and is
subdivided into the Paleozoic era (to 225 mya -- million years ago),
Mesozoic (to 65 mya) and Cenozoic; for convenience these are further
subdivided into periods.
The 70 million years of the Cambrian period gave rise to every phylum of flora and fauna
recognized today; the increase in number of distinct species has been called the
‘Cambrian Explosion.’
Let us interrupt the saga to insert here the divisions of geologic time and the
developments that characterize the divisions.
The Paleozoic era is divided into periods:
The Mesozoic era is divided into periods:
The Cenozoic era is divided into the Tertiary
period (65 to 0.6 mya) and the Quarternary period (600 thousand years
ago -- tya -- to recent times). Epochs in the Cenozoic era are:
We are accustomed to indicating time by elapsed time to the present, but let us turn it
around to elapsed time since the formation of Earth. At 4.6 billion years for Earth’s
age, it was 0.85 billion years before those deposits in Greenland (Isua), or 1.0
billion before sediments suggest actual cells, or 2.5 billion for algal reefs, or 3.2
billion before cells of more than a very simple design, or 3.5 billion for green algae.
Some 4.0 billion years before evidence of multi-cellular creatures (soft-bodied
animals). All calcareous fossils (those with shells or bones) were produced in the
last 600 million years.
Historically, our knowledge comes from specific finds, most located quite by accident
despite our present knowledge of the kinds of places to look and the kinds of places
in our world today. Many of those creatures had skeletons and teeth (which usually
are harder and preserve better than bones). Lagerstatten, Burgess, Hunsruckschiefer,
Mazon Creek. My interest does not embrace the time sequence for locating
the various strata, their locations and their interpretations, or fitting together the jig-saw
puzzle of geologic time from correlations of fossils with position within layers of the
strata. The purpose here has been piecing together the grand picture as a backdrop to
appreciation of pictures of fossils and their place in our understanding of Earth’s
history and the origin of species.
If the primeval gases were swept away then the early atmosphere was likely rich in
carbon dioxide, water vapor, hydrogen sulfide, hydrogen chloride, carbon monoxide
and hydrogen although the free hydrogen as well as hydrogen resulting from breakdown
of water may have escaped. Free oxygen was likely not a part.
The oldest sedimentary rocks are dated at some 3.8 bya -- Isua,
Greenland -- and they include deposits that are arguably evidence of organic life because
the ratio carbon12 to carbon13 is taken as evidence of photosynthesis. Sediments
dated at 3.5-3.6 bya include actual cells -- structures that are today associated with
blue-green algae, which are unquestionably plants. By 2.8 bya there were very fine
filamentary structures, which are almost certainly of biological origin. There was still
very little free oxygen in the atmosphere, but evidently enough to form sufficient
shielding from ozone to protect the surface from harmful radiations from space. But
until some 1.4 bya all evidence suggests very simple single-celled creatures; it was at
1.4 bya that single-celled organisms of a more complex design emerged. (Barely before
the Cambrian explosion of diversity, the multi-cellular creatures found at Ediacara may
reflect a failed experiment in multi-cellular design.) By .67 bya the oxygen level had
reached perhaps 7%, and there is evidence of abundant but primitive life.
The Burgess find, dated at some 530 mya (million years ago) -- .53 bya -- is likely the
most complete of that period as yet found. The Burgess shales reveal a tremendous
proliferation of multi-cellular soft-bodied fauna including variations in body design
that now have long been extinct. Undoubtedly single-celled creatures preceded them
and the Burgess reveals the flowering of very diverse patterns for life. There were
many basic designs for life in the Burgess Shales, but other designs disappeared later
in the Cambrian period and DNA survived to become the model for all multi-cellular
life today, the dominant means of passing on bodily designs. But note that these are
all soft-bodied creatures; preservation of patterns that can be construed as fossils
depended on rapid in-filling or overlay by sediments that would withstand the ravages
of time.
It is perhaps surprising that the fossil record has been developed as completely as it has.
Combinations of the conditions for preservation are rare although dozens of sites were
found during this past century. Hundreds of sites of varying antiquity are known,
scattered over Earth's crust. Perhaps as we understand more fully the kinds of events
and conditions that preserve fossils we will explore more deeply into that crust.
Examination of what fossils have been discovered reveals nothing in the way of
transitions from one reptile to another: There have been many distinctly different
dinosaurs but there is nothing to show the steps by which one evolved from an earlier
creature; perhaps in time enough treasures will be uncovered to fill in such chains.
There seems no finality in the state of our knowledge of our own past. New finds
alter our understandings, such as evidence found in Colorado that plant life
rebounded more quickly (1.4 million years rather than 10+ million) than previously
thought after the mass extinctions that ended the Mesozoic era.
Regarding SETI (the Search for ExtraTerrestrial Intelligence), there can be no doubt there
are in our galaxy alone millions (perhaps billions) of stars with planets of a temperature
range appropriate to host life forms. But, considering that the Sun and its planetary
system must have included the remnants of a supernova in order for it to have the heavier
elements necessary for life processes, the number of prospective hosts is only a fraction
of those with an appropriate temperature range. In my view there are likely at least
thousands of planets in our galaxy that could host life based on carbon and water. And
we should admit there may be other chemical bases for life despite the necessary
characteristics of their pervasive fluid to share with water two necessary properties:
(1) be a near-universal solvent and (2) expand upon freezing (so there can be space for
gases between liquid and solid in order for atmospheric ingredients to circulate above,
and participate in the life processes in, that fluid).
Regarding our solar system as a gigantic heat engine, we estimate that our Sun should
continue to provide reasonable warmth for billions of years, well beyond Earth's
habitability. Earth's crust provides excellent insulation, but the heat from the core is
radiating into space; lest there be an immense reservoir of radioactive material in the
core -- which will eventually be spent -- our planet will continue to cool. But I think
we can safely estimate that Earth will remain hospitable to human life for yet millions
of years, possibly time enough to gain a complete understanding of our past and
our surroundings -- if only we will exercise prudence in our husbandry of what our
good fortune has provided.
Our civilization has not become aware of an earlier high civilization on Earth although
earlier extinction events may have fatally disrupted its advance, or valleys between
glaciers may have hosted developments that were destroyed by advancing or
receding glaciers. Of course cultivation of high civilization may once again be
interrupted by natural events (such as ended the dinosaur era) such as the volcano
Toba or the culmination of conditions developing under Yellowstone. Perhaps,
being forewarned, mankind will be enabled to foster the will and science to forestall
such "extinction level events."
But it is now appropriate to enjoy a display of the creatures that have been found or
inferred from the remains available to us.
It is well beyond my intent, nor indeed my educational preparation, to undertake
correlations with the changing geological characteristics of Earth, changing weather,
rise and fall of the oceans in eras of warmth and cold, and the gradual increase in
complexity of life forms influenced by these changes. That is the domain of the
professional who has committed his life to exploring, studying and correlating these
complexities.
This was written with the expectation it would be the introductory chapter of a book
of photographs and artistic renditions of fossils and ancient creatures. However, in view
of my age and other present interests, I doubt my life span will allow the extended
travels necessary to accumulation of photographs and their presentation; hence, this
work ends here. I am still hopeful of finding a text that correlates datings of geologic
strata and fossil finds, especially from the Jurassic period to modern times. I can be
reached by e-mail by clicking here.
It seems true that, the more we learn, the more we realize how great our ignorance.
There will forever be mysteries enough to attract those of exploratory bent. It is an
adventure of mind that continues to unfold.
For Contents of Ken Wear's web site, click here.
Then and now, here and there in the seething caldron of nothingness there is an event
resulting in emanation of particles and/or energy. For the most part these particles
likely recombine instantaneously to leave an undisturbed nothingness as before. But
occasionally two or more events occur close enough together in time and space that
they influence each other in some way and therefore cannot mutually annihilate all
products of the events. There is a residue of matter and/or energy. It should be
expected that, with time and despite an exponential decay in generation as space
fills, particles and energies accumulate and interact to produce matter -- protons,
electrons, leptons and other combinations, some of which may have escaped our
observation.
From nothing, over incalculable stretches of time, there arose a collection of particles
and energies producing enough matter that gravity asserted itself and brought together
large and larger masses. It was a very uneven or non-homogeneous sea of particles.
And, being non-homogeneous, there were various centers of gravitational attraction,
some in time accumulating enough mass to compress and ignite the fusion process.
Perhaps many such accumulations combining for a Bang or two here and there.
Perhaps a Modest Bang. Perhaps expanding until gravity dictated otherwise, arrested
expansion and drew the matter back together for a Bigger Bang. Perhaps Bangs of
various sizes at various regions in that unimaginable expanse of what used to be
nothingness. (The virtual aspects may have combined to become organized as hosts
of beings possessed of intelligence.)
So that is my picture of how it all began -- an inevitable outgrowth of the initial
nothingness.1 (To view footnote,
click here. (If you wish, assume a deity
arose from the same nothingness, perhaps through other combinations of
non-matter or virtual aspects of that seething caldron.)
Doubtless theoretical minds can work both sides of this fence and generate theories
in support or in contradiction. I am more content with the gradual creation and
evolution of the Universe over trackless time than I am with the sudden explosion,
with no preceding preparation, and of such magnitude as to generate in one swoop
(in 10-40 or less seconds) all that we have been able to see with our
telescopes.
Considering the restless and energetic nature of the surface of that young and cooling
globe, with the constant churning of waters with their varying chemical solutes and likely
chemical reactions, crystal growths and chance interfaces, it seems unreasonable to
suppose that nowhere in the vastness of Earth’s surface seas, at no time in a billion years,
could the right elements come together in the proper proportion to form a molecule of a
nucleic acid surrounded by a protein sheath. So long as it can grow through attachment
of other like molecules, finally breaking because of excessive length and the parts
continuing to grow as by crystallization, we have mechanisms for nourishment, growth
and reproduction. Once set in motion, with here and there a different chemical element
being incorporated, it would seem more or less inevitable that something akin to life
would come into being. And once started, proliferation; and with proliferation, variation.
“Something akin to life.” Granted the enormous complexity of DNA’s double helix, with
its immense variety of combinations of the chemical elements, it seems more reasonable
to suppose there were precursors, perhaps chains of developments in various directions.
Many precursors. Precursors to the precursors. But, once the double helix arose, all
other formulations were overshadowed and lost. And, once set in motion, DNA was
unstoppable.
Big Bang
Modern thought seems to be dominated by the idea that, initially, there was nothing,
and there was no time -- just empty space or perhaps not even space -- simply a void
or, indeed, nothing at all. Then, due to cause unknown, there erupted at a
minute spot somewhere in this nothing an event akin to explosion that spread and
expanded -- and cooled -- and eventually formed these billions of galaxies each
with perhaps billions of stars each of a mass almost incomprehensible to us mere
mortals. My mind is apparently too small to comprehend the magnitude of such
an event that could, instantaneously, from a single point in nothingness, with no
preparation, produce such an array of solid bodies; my notions of science
contradict that kind of event or that big a Big Bang.
An Alternate Beginning
Initially there was nothing -- absolutely nothing -- in all of the universe -- in that
unending expanse of nothingness. Time always was, though there were no events
with lapses between so that an assessment of time’s passage had meaning.
Physicists have reported that, in a volume from which all matter has been exhausted,
there remains a nothingness that is a seething caldron of activity, generating and
extinguishing particles and virtual particles unceasingly. We thus have a mechanism
that is capable of extension and is intuitively, to me, a much more likely scenario than
that unimaginably huge Big Bang springing instantaneously, without preparation,
from the same nothingness.
Astronomy
We should view our universe as dynamic, with processes of generation and annihilation
of mass, attraction and repulsion, combining and dispersing, broadcast and reception
of energy, continuing unceasingly throughout. A seething turbulence on a grand scale.
Yet on a scale that is local in time and space -- exceedingly minute in both time and
place -- conditions may permit life to evolve and prosper and diversify and ultimately
observe that continuing turbulence on its seemingly infinite scale.
Formation of the Solar System
Many nebulae -- concentrations of gases, particles and debris resulting in many cases
from supernova and heated by various energy sources -- are visible in our telescopes.
Considering the range of elements in our Earth’s crust, it is likely that much of the matter
from which our solar system was formed consisted of remnants of a supernova of a
large star, which may itself have included heavier elements formed by an earlier
supernova. Our solar system likely had its origin in a nebula of such concentration that
gravity commenced to pull it all together. It shrunk -- contracted -- and the heat of
compression raised the temperature in the central portion faster than the heat could
escape. And with compression, with its concentration of mass, came stronger
gravitational attraction.
Formation of Earth
If Earth was cast off or yanked away from a young Sun, its temperature was well above
the melting point of all constituent materials. If the accretion disc separated into rings
and collapsed to form planets while the Sun was coalescing, then Earth’s initial
temperature may have been much lower, yet apparently adequate to melt all of its
constituents. What gradients of temperature existed within the accretion disc due to
gravitational compression and energies of impact during the accretion process? That
is an interesting exercise in speculation.
Early Earth
It doubtless took hundreds of millions of years for Earth to cool enough for life to
take hold. (In my readings I have not come across a speculation about Earth's
thermal history.) Without considering the time sequence of events, it is interesting
to contemplate the variety of forces that have contributed to Earth’s history.
Geologic Time and the Fossil Record
We commenced this discussion with Cosmogony (the study of the origin of it all),
continued with Cosmology (the ordered celestial system), and now turn our attention to
Earth itself and its Geology (formation of rock strata and their contents). Earth is a
dynamic engine where periods of upheaval may deform rocks, fold them, tilt them,
fracture them. While there are relatively few locations on Earth’s surface where the
combination of lack of vertical movement and very little erosion have left initial rocks
exposed so they can be studied, there are locations where meteorites have apparently
been undisturbed for billions of years. But it is the study of stratified rocks, those
formed from sediment, that forms the basis of geological mapping. Outcrops, once
found, may be analyzed; the resultant geological maps have been prepared for most
regions of Earth, even Antarctica and beneath the oceans. While fossils were at one
time regarded as “sports of nature” the sheer number of fossil finds plus the
development of a rational ordering based on rock strata gives us sound reason to
feel they represent life as it evolved during Earth’s past.
Origination of Life on Earth
Life! What amazing complexity in the simplest organisms yet identified! Fungi, viruses,
algae, bacteria, yeast, protozoa. Singly or clustered or in colonies. Some members
specializing in function. Single cells with a nucleus and sheath and intervening particles
to perform specific functions. Multi-cellular organisms with cells specialized to specific
functions. Fathoming the development of life from a slurry of chemicals is one of
science's most intriguing and daunting challenges.
Cells are the smallest structural units capable of functioning independently. - hair - 10 x cell or 100 x bacteria cell 10 x bacteria bacteria 10-6 m virus 1/10 of bacteria DNA 1/10 of virus or 1/100 of bacteria molecule 1/5 of DNA atom 1/10 of molecule or 10-10 m
Viruses are not alive in the strict sense of the word but reproduce and have an intimate
relationship with living organisms.
It is difficult to conceive even the simplest DNA or virus arising spontaneously from
the primordial slurry of chemicals, so there must have been precursors that have escaped
our attention or may have disappeared with the advent of DNA.
Continuing Development
We could discuss two time lines for the evolution of life -- one for the oxygen-producing
organisms and one for the carbon dioxide-producing organisms -- plants and animals.
Since the early atmosphere was primarily carbon dioxide and the oxygen content is
estimated at only 7% seven hundred million years ago, plant life was obviously favored
in those early days and early animal life did not require the percentage of oxygen we have
today. Chlorophyll or a similar agent for conversion of sunlight to plant energy obviously
evolved long before there was any necessity for the proteins of animal life. Looking at
the chemical analyses of the four chlorophylls
(C40H56,
C46H56O2, C55H72O5N4Mg, and C55H70O6N4Mg) and the slow development of atmospheric oxygen, it is
evident that chlorophyll itself has evolved and that suggests earlier precursors to the
most primitive plants (algae).
Metazoa (animals)
Plants (of the lowest group of plants, thallophyta, some are algae
and some are fungi)
Fungi
Protistans (mostly single eukaryotic cells: amoeba, algae; includes seaweed,)
Monera (single prokaryotic cells), which have more recently been sub-divided into
archae (bacteria) and eubacteria
Although enormously complex, prokaryotic cells are the simpler; they possess DNA
that is not enclosed in a nucleus and there is little internal structure. Eukaryotic cells
are larger and have a complex internal organization including a nucleus which houses
the DNA in chromosomes, and specialized structures called organelles that are
responsible for such processes as digestion, initiation of division, excretion, etc.
Plants have chloroplasts which house the chlorophyll.
GEOLOGIC TIME
For convenience geological time is divided into eons dating from the formation of Earth,
and all geological subdivisions are based on characteristic developments during that
interval of time (as they were understood at the time the system was developed).
Radiometric dating (radioactive decay) of the age of some of the oldest
meteorites (chondrites) yields an age of some 4.7 billion years, and geologists take that
as the likely age of Earth. From then, the Hadean eon persisted for 0.7 billion years
or until 4.0 bya -- billion years ago. There is no estimate of events during that time.
Cambrian (from 570 million years ago -- mya -- to 500 mya) during which there
were shallow seas and the first abundant record of marine life, especially trilobites and
shellfish; evidence of all plant and animal phyla; while the seas were teeming with life,
the land was a vast desert with at most a veneer of primitive vegetation (around water)
and no animals.
Ordovician (500 to 425 mya): mountains elevated in New England with
volcanoes along the Atlantic coast; much limestone deposited in shallow seas; great
invertebrate animals; the first marine vertebrates (including jawless fish).
Silurian (425 to 405 mya): mountains formed in NW Europe, the first small
land plants appeared (reproduction by spores), corals built reefs in northern seas,
shelled cephalopods were abundant, and the first jawed fish appeared.
Devonian (405 to 345 mya): Age of fishes; New England mountains raised,
land plants evolved rapidly, seed plants and large trees appeared; first sharks, insects,
land animals and amphibians appeared.
Carboniferous period is divided into the
Mississippian (345 to 310 mya): land plants became diversified, sharks of
relatively modern types appeared, land animals little known
Pennsylvanian (310 to 280 mya): mountains grew along the east coast of
North America and in central Europe, coal swamp forests flourished, seed-bearing
ferns abundant, cockroaches and first reptiles appeared
Permian (280 to 230 mya): folding of Appalachians and central European
mountains, glaciers in the south and reefs in warm northern seas, trees of coal forests
declined, ferns abundant, conifers present, first cycads and ammonites appeared,
reptiles surpassed amphibians; trilobites extinct.
The Paleozoic era ended with a mass extinction that
destroyed 96% of species of marine animals and 70% of species of land animals.
(The Permian/Triassic extinction has been more accurately dated at 252.6 mya.)
Triassic (230 to 180 mya): lava flows in eastern North America, ferns and
cycads dominant among plants, modern corals and some insects of modern types
appeared, expansion of reptiles including earliest dinosaurs
Jurassic (180 to 135 mya): Sierra Nevada Mountains uplifted, primitive birds
appeared
Cretaceous (135 to 65 mya): Rocky Mountains began to rise; most plants,
invertebrate animals, fish and birds were of modern types; dinosaurs reached maximum
development and became extinct, and mammals were small and very primitive. It has
been suggested that, during portions of this period,
CO2 was 2%,
O2 30% and atmospheric pressure 20% higher
than today.
The Mesozoic era ended with extinction of the
dinosaurs (and more than half the biological families), presumably as the result of a
massive meteorite striking Earth; that event allowed mammals to proliferate.
Tertiary:
Paleocene (65 to 55 mya): primitive animals developed.
Eocene (55 to 35 mya): Rocky, Andes, Alps, Himalaya mountains raised,
primitive horses appeared.
Oligocene (35 to 25 mya): many older types of mammals became extinct;
mastodons, monkeys and apes appeared.
Miocene (25 to 10 mya): renewed uplift of Rockies and other mountains;
great lava flows in western U.S., mammals began to acquire modern characteristics;
dogs, modern horse, man-like apes appeared.
Pliocene (10 mya to 600 tya): earliest ape-like man appeared in Africa.
Quarternary:
Pleistocene (600 tya to 12 tya): glaciation, great mammals, modern man
late in system.
Recent (12 tya to today): glaciers only in Antarctica and Greenland, many
giant mammals became extinct, spread and development of modern human cultures.
The discovery and development of agriculture, so that the quest for food did not
monopolize our time, allowed leisure to pursue intellectual activities, which has led
in turn to exploitation of natural resources for our convenience and pleasure, as
well as extension of our physical and observational powers.
Today: It is important to note that geologic time has not ended, but today
is part of the chain of development2 To view
footnote, click here Mankind (1) stands on
the threshold of extending his mental powers through use of the computer and enhancing
his innate capabilities through knowledge of the human genome and (2) possesses the
capability of either extending his exploration to other worlds or destroying himself and
all his intellect has produced.
Postscript
To those of a deistic or religious bent: The absence of fossils showing gradual change over
generations of a species, leading to a new species, suggests an Intelligent Designer. There
can be no doubt that evolution is at work for we are seeing in our time development of
‘super-germs’ that resist our medications. But I am impressed by the diversity of animal
life on Earth and the number of generations needed, say, for the gradual extension of neck
to form a giraffe, or extension of a nose to form an elephant, since each incremental
change must require many generations for that change to become widespread enough to
become the basis of a population adequate to be the starting point for another incremental
change. It seems much more credible that an outside agency produced changes than that
willy-nilly mutations (and their survival because of better adaptation) created all species;
there would therefore be no transitional species but quantum jumps from one species to
another (but related) species.
Footnote1
For a more elaborate presentation of the process,
click here to read my essay "Was the Big Bang the
Ultimate Beginning?"
This footnote will come into view
again at the end of this presentation; you may then link and avoid the distraction of
linking now. The BACK button should return you to mention of this footnote.
If you are of a theological bent, you may understand and appreciate this
essay [click here] dealing with evolution,
Evolutionism, Creationism and Intelligent Design.
For comment on the effects of modern medical practices on evolution,
click here.
Or a lecture on the beginning of stars and end of intelligence appears if you
click here.
Further description of "An Alternate Beginning"
Speculations on the origin of life
Let me join the speculation on how life originated by, first, pointing out that the forces
of Nature were much more violent then than today and no doubt erosion much more
rapid where there were surface liquids. I can visualize, in a surface liquid pool in which
myriad chemicals have been dissolved, a rod-like crystal growing and reproducing by
fracturing along its length. A crystal sheath grows along the rod’s length; perhaps
another sheath of different composition grows around that. One would think that,
quite by chance, amino acids would be among the chemicals formed as constituents
of the chemical ooze. And, over time, chemical exchanges occurred between the central
rod and one or both the surrounding sheaths. Nourishment was available due to the
continued churning of water with its erosion and delivery of water-borne chemicals.