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In the chapter on Creation we discussed the evidence that life maintained the level of the single cell for billions of years before it progressed to increasingly more complex, multi-cellular organisms. In the chapter on Ontogeny we discussed how each organism develops from a single cell passing through millions of stages of development before it reaches the form of the mature organism. During this period the organism ingests lifeless matter which self-assembles into a living part of the organism. Due to the similarities of these early developmental stages in related species it can be said that Ontogeny recapitulates itself to some degree with each evolving species. There are many similarities in the early development of a flat-worm and a human, for instance. Just the idea of an organism composed of billions of cells was unheard of till the 1600's, which is a relatively short time ago. It's no wonder that evolution is still a question of debate for many people. Even though 99% of the species which ever evolved are now extinct, there are species remaining, having found their niche, similar to even the earliest stages of the formation of life billions of years ago. From this we can say that phylogeny is related to paleobiology in that the fossils of the simplest organisms are the earliest in each period. Ontogeny, Phylogeny, and Paleobiology are all aspects of cellular life that point to an ever evolving world of cellular life. Many clues as to what has happened continue to exist today.
Chemical communication
In the last chapter we discussed
cellular life three and one half billion years old after they had first
developed cell walls to protect "life" from the environment. These
walls did not isolate them, however. Each of the early aquatic cells secreted
simple chemicals and organic compounds which were encountered by nearby cells.
This still occurs today, even between the cells of our own body. Some of these
bi-products were absorbed or enveloped to become active factors within another
cell. Organic bi-products thus exchanged were but a step from hormones, and not
only could serve as food, but also could serve as structural models for
replication as DNA and RNA.
Electromagnetic fields in the sea
A second type of early communication
and activity was electromagnetic. Whenever a chemical interaction takes place,
there is an exchange of electrons between the elements and compounds involved.
This exchange of electrons is the basis of a current of electricity creating a
slowly fluctuating electromagnetic field. These electromagnetic fields were
effective over a microscopic distance within and outside the cell. A proximate
cell could be attracted or repelled; depending on the orientation of the
electro-magnetic fields and the temperature of the environmental fluids. As the
temperatures increase, the chemical reactions speed up and there were larger
flows of electrons. A larger flow of electrons causes more intense electromagnetic
fields around the cells. These electromagnetic fields were enhanced a bit where
more than one cell held together in an unorganized fashion. In such a case, the
extension of the electromagnetic field outside a random multicellular
individual would be just a bit greater than outside a single cell. This would
greatly extend the size of the electromagnetic field outside the animal. An
elelctromagnetic field is polarized with north and south poles. This could have
had some effect in determining heads and tails of the first multicellular
animals. In more advanced animals the placement of the head and tail is
determined by hormones in the mother's womb.
The effects of these electromagnetic fields can be grossly observed in schools of fish which all face the same direction. As their environment is warmed, they move farther apart and come back closer again as the water is cooled. This parallels the increased metabolism with warmth and decreased metabolism with cold, and the corresponding increase and decrease of the electromagnetic fields around the fish. Some idea of the extent of these fields can be appreciated when one considers how some bottom feeding sharks can detect creatures camouflaged by a slight cover of sand and mud by their electromagnetic field effects. The sharks can be tricked by putting coils of current carrying wire under the surface of the sea bottom. The fluctuations of the electric fields are on the order of seventy per minute.
Electromagnetism and land animals
This electric interaction between
individuals has only been observed in an ionized liquid environment, such as
the sea. This was retained and neatly modified during the history of evolution.
In a dry non-conductive atmosphere the direct electric interaction between
individuals would probably be negligible to non-existent, but still could act
within the sea inside our skin. Our experience with electrocardiograms,
electromyograms, and electroencephalograms attest to that. These are all
functional consistencies with basic elemental physics within life.
Contractile proteins
The most important development
within the unicellular animals must have been contractile protein strands. They
consisted of two types: microtubules and microfilaments. These strands probably
first promoted the circulation of fluids with solid particles with streams
inside the cells. This greatly enhanced digestion, growth, and development. The
contractile strands also attached to the cell membranes, probably first to
increase the efficiency of internal circulation, but secondly to enable the
reactivity of the cell. It could retract away from an unwholesome element and
extend to get nearer a wholesome element. Extension and contraction could soon
take on characteristics of pseudopodia and give motion to the cell. Reactivity
could then be greatly extended and promote survivability of the cell. One can
observe the living ameba under a microscope, carefully testing the chemistry of
it's surroundings, seeking the trails that lead to the wholesome environment
and withdrawing from the chemistry of the unwholesome environment. On a more
sophisticated scale, organisms do the same thing.
Combination cells
Another phenomenon appears to have
occurred early in the evolution of single cells. Several organisms may have
become first parasitic (An organism that grows,
feeds, and is sheltered on or in a different organism)then saprophytic (An
organism, especially a fungus or bacterium, that grows on and derives its
nourishment from dead or decaying organic matter) with each other. One
can visualize a protozoan with spirochetes (a spirally
coiled rod like bacteria) as parasites. Due to the parasites, the
protozoan needed more food. For this the spirochetes might help by sticking
their tails out and propelling the protozoan around over a larger area where it
might encounter more food. Within the protozoan itself, saprophytic bacteria
could assist in the digestion of ingested food. Such a combination of creatures
exists in the intestines of termites. As time wore on, over a couple of million
years, their genetic codes merged and the protozoa reproduced with cilia and a
free floating internal digestive apparatus which enables termites to digest
cellulose, and thus eat wood. The mitochondria within the individual animal cells
are a much more common example of separate genetic inheritance. In mammals the
mitochondria are inherited only through the females.
Cooperation, communication, and synchronization
Dictystellium discoideum, in
particular, are a great model for biological "altruism". Normally
they grow as solitary amoebae feeding on bacteria. They are classified as
eukaryotes, between plant and animal. When food is scarce they aggregate to
form a multicellular pseudoplasmodium. This gathering of single, genetically
similar cells tends to orient towards light. Ultimately the front end will stop
as the back end catches up and culmination begins. Stalk cells form at the tip
and flow through the cell mass in a reverse fountain pulling the remainder of
the cells skyward. The stalk cells will die and serve to support the final
spore mass at the top of the fruiting body (the sorocarp). The protected spore
mass consists of a drop of fluid within which are suspended viable spores that
will start the next generation.
The Multi-Cellular Animal.
Somewhere along in the early evolution a negative mutation must have occurred which prevented the complete dissolution of a dividing, proliferating cell. The two cells stayed together. Cells with this fault had to cling together and fend together as a multicellular community. The first multicellular material must have been spherical and oblate, drifting and rolling from place to place with the currents. Examples of these are seen today in the open sea and have been photographed as loosely connected cells in a "glob", sometimes, twenty feet across. This must have led to many accidental deaths as the currents transported the communities to non-viable areas.
The rigid ball
The more rigid communities of cells
were occasionally able to cling to a viable area and wait for the currents to
bring nutrition to them. With the rigid ball, to prevent the middle cells from
being cut off from nutrition and starving to death, the ball became involuted.
This formed the anlage of a hydra.
The tube
Once upon a time, a hydra had a
destructive mutation that caused some of the cells in the bottom of the cup to
dissolve, and a tube was formed. Once a tube worm was evolved, one might guess
that the evolution of man was inevitable (sic). Once cells began holding together
in communities, some cells could lose some of their vital functions through a
negative mutation, but would depend on the other cells with that vital function
to keep them alive. These cells could then concentrate their vital energies on
what was left, and specialization evolved. Once specialization evolved, a
community of cells could function as an individual with systems: digestive,
nervous, supportive, reproductive, respiratory, integumentary, secretory, and
defensive.
The early nerve
It was probable that a cell within
an early multi-cellular individual was squeezed and moved around among the
other cells within, leaving a trail of its own reactive substance behind. Thus,
a stimulation of its body carried a reaction along its extended length stimulating
many other cells along the way much as a nerve cell would. This would have been
eventually exploited for coordinated activity that would have promoted the
viability of that multi-cellular individual. A type of compliance with the
Trinity of Science of repeatability, reliability, and consistency is seen in
nerve cells today. Nerves serve the function of rapid electromagnetic
conduction from one end to the other which internally corresponds with electron
shifts at least from one side of a molecule to the other. This activity causes
a chemical reaction at the head end to be reflected in a hormonal secretion at
the tail end without the transportation of material over the route in between.
This economy of reaction makes a rapid recovery to the original conductive
state feasible. Repeatability was therefore quickly assured, as well as
reliability in conduction, and consistency of distant reaction.
First invaders of the land
As recently as four hundred million
years ago, plants first invaded the land. Lichens, a combination of fungi and
algae, probably led the way. Fish that invaded the fresh water streams had to
develop stronger skeletal systems to resist destruction in the buffeting
currents. These were the bony fish in distinction from the cartilaginous fish of
the sea. Like the bony fish land animals and humans evolved hard skeletal
systems. Lung fish are often cited. These fish live in streams that seasonally
dry up, and can burrow into the mud and breathe air to survive the dry spell.
This creature has both gills and lungs. Salt estuary and tidal marshes bring
sea life into contact with land plants. Adjacent stores of food attract sea
life into a new zone. Varieties of sea species occurred that could take
advantage of the new source of energy on land. When the varieties have been
separated long enough so that they can no longer relate genetically, by
definition, a new species is born. It should be reiterated that, although there
is fossilized evidence of many of these steps progressing through time, we can
surmise the greater part of this description from observing the development of
each organism alive today, including the human being. This process is called
Onogeny: the previous chapter. Another reason we can surmise this description
of evolution is because of the variety of creatures still existing today. This
variety has been carefully catalogued by complexity and analyzed by similarity
in the science of phylogeny. The reason there exists representatives of many
stages of evolution today is because of the principles of evolution and,
especially, the survival of the "fit and capable". These examples
have found a niche in the environment that has stabilized them for millions of
years.
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DNA alteration: mutations
Mutations are possibly dependent on the presence of carbon-14 to alter DNA. Those which
add something are called positive mutations. Mutations which subtract something
are much more prevalent, and are called negative mutations. Mutations usually
mean that the individuals inheriting them are non-viable. Mutations involving
minimal areas of an animal's system sometimes do not kill the animal and are
the typical method of alteration. Viable mutations are extremely rare and do
not generally reproduce. They appear as freaks and cannot find mates. In
domestic animals slight, desirable mutations are protected. Mutations survive
under domestication that would die out in nature. We favor white chickens, but
must protect them from hawks who also favor them in the wild where their
non-camouflaging color fails to hide them. Under domestication individuals are
not so selective of their mates. Zoo keepers are often chagrined when two wild
animals refuse to mate where domestic animals would take quick advantage of the
coupling.
Sexual-mate selection guides the direction of slight randomly changing DNA traits. Here life has the opportunity to combine two individuals who already have successful, viable traits. If two individual organisms which are slightly larger mate, their progeny will probably be slightly larger. This type of increase can continue, taking advantage of every slight advancement toward the sexually desired effect. Those traits which are sexually non-viable will die with the individuals who possess them, and they will not be passed on. Only a few thousand years ago, all dogs were apparently wolves. With the wide variety of pedigree dogs available today, one can easily see how flexible genetic engineering through sexual selection can be. For another example, all vegetable produce we buy in the super-market has been bred for color and taste. These are examples of man made evolution.
Geographic isolation
Environmental challenges
Predator and prey
Extinction
Strains, varieties, and species
With all this emphasis on challenge and change, one might think that life
would be a quickly, ever
changing kaleidoscope. However the unchanged lineage of the sow bug can be
traced back 400 million years. Baboons existed long before any traces of humans
and have not changed. Although thousands of species that we find in fossils are
now extinct, we find many fossils of creatures alive today, such as the hydra,
which date back hundreds of millions of years unaltered. This is because they
have found a niche in the environment that has not changed for which they are
"fit and capable". To explain this, let's consider the Giraffe.
The Giraffe: fit and capable
The purpose of this chapter is ultimately not to debate the occurrence of evolution
but to give it a place in any system of belief which is congruent with what little we
know about our world. The fact is that evolution has resulted, though the road
has been long and winding, in "US", you and me. Looking at it from
the perspective of the Realistic Idealist, evolution is the manner that G*D
created us. The fact that our creation has been nurtured and guided so
carefully by G*D is proof that we are special and not some accident of chaos.
This allows minor alterations of
little or no consequence to be developed. An example of this is the distinct
coloration patterns characteristic of two strains of the same squirrel on the
north and south sides of the Grand Canyon. Because some organisms are isolated
on different land masses, they can evolve independent of each other. An example
of this is the variation of animals produced by isolation in Africa and in
Australia.
An environmental change can sometimes make the difference between survival and
extinction. An example of
this is the gray moth observed in England at the beginning of the industrial
revolution. As the soot from the factories covered the trees and houses, the
gray moth became easy for its predators to see. The result was that only the
brown variety survived. Extinction
The principal cause of extinctions is change in environment. We are only now
realizing the significance of the iridium rich layer that caps the dinosaur
age. The iridium, exclusive to cosmic bodies, signifies the impact and
explosion of an asteroid on the Earth. The remains of their craters also date
their impact. This caused so much dust in the atmosphere that we theorize it
changed the climate of the Earth radically enough to extinguish most of the
dinosaurs. Over millions of years, continents have drifted and turned taking an
environment from a torrid tropical zone and inserting it into an arctic zone.
Mountain ranges have risen dividing species and subjecting the divided parts to
changed climates. Continents submerged and rose again. Inland seas were formed
and dried up. All that geological turmoil, over long periods of time, caused
drastic changes in climate. It radically changed a species which accommodated
and wiped out others that could not.
We are having difficulty growing away from the idea that "a species becomes
extinct through losing a
competition with a better equipped species" as a major factor in
evolution. It has occurred, but competitions usually cause balances; not
extinctions. The competition of predator and prey has brought about some few
changes, but, maybe, not as much as may be expected. As a predator develops,
the prey develops defenses. There is a combined evolutionary drift as both
predator and prey develop until they both reach some limiting factor. Both may
increase in size until size becomes cumbersome, then both stabilize around a
certain weight. Strength of biological materials is the basic factor. If the
predator were too successful, it would wipe out its prey and starve to death.
Actually, when the prey are depleted, the biggest and strongest predators die
first, because they need the most food, then the prey can multiply again.
Eventually the involved genetics come into balance and the predator and prey
survive together, stabilized.
There have been numerous points in the history of the earth where, due to some
environmental challenge such as a massive asteroid collision, large segments
of all life on earth have suffered extinction; thus, making way for the evolution
of other less competitative life forms. There is evidence that the extinction of the
dinosaurs made way for the evolution of mammals.
Populations of organisms that become
separated by environmental barriers change first into different strains. If the
environmental challenges are different enough, the organisms develop into
different varieties and then different species. Sexual-mate selections drive
the DNA traits while environmental challenges cause extinction of the
individuals with unsuitable traits. "The fit and the capable survive and
reproduce while the unfit do not." The Fit and the Capable
Giraffes ordinarily grow to sixteen feet, though they can occasionally reach
seventeen feet eight inches. A sixteen
foot giraffe is confined to an open savanna with frequent clumps of mimosa and
acacia. They browse on the leaves of mimosa and acacia which are short trees.
Such an animal cannot run into a jungle and woods. A forest is as effective as
a chain fence in retaining them to the open grass lands. The animal gets most
of its water from the juices of the foliage. To actually drink water, which it
seldom does, it must clumsily spread its front legs wide, so its mouth can
reach the water surface. A seventeen foot giraffe is too tall and is burdened
by a heavier neck. Any giraffe less than fifteen feet cannot reach most of the
branches. Fitness in height is a narrow band between fifteen and a half and
sixteen and a half feet tall. Any individual that does not fall within that
band of fitness is less than fit and may not survive under conditions of
greater than usual frustration. Whatever it takes to make an individual fit,
more than that makes for less fitness. It is not always clear how an animal is
confined to its environment, but there is some confining factor in most every
animal's way of life. Confinement and fitness limit many species and prevent
further change. Robber flies, and opossums are ancient unchanged species. Man
has changed vastly, however. Fitness can be as stable as the environment the
species inhabits. The genetic code of such confined, fit species becomes very
rigid. For example, with the exception of the white turkeys, breeders have been
unable to alter them. Seals, frogs, turtles are limited to a narrow zone of
water and land near the water's edge where they must return to reproduce. At
these borders we are often impressed with animals that can creep up and stay a
while. Some individuals can stay longer than others. The dividing boundary
between water and land separated varieties into species of plants. The
boundaries between sea and land and air separated varieties of animals into
species. After a while the same boundaries separated varieties of plants and
animals as they recrossed the boundaries from air to land (ostriches), from air
to water (loons, penguins), and from land to water (seals, whales). Other types
of boundaries separate varieties that may become species; climates: moist to
arid, and hot to temperate to cold.