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   Creationism vs Evolution Debates
     The Science of Evolution
       Mechanisms producing Evolution

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FreeAmerican

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Evolution is a process of successive alterations of DNA nucleotide sequences and gene groupings, copying errors, replication repeats, deletions, translocations, enzymatic lysis of nucleotide sequences, viral DNA insertions, radiation damage to nucleotide sequences, the effects of transposon genes, and perhaps extra cellular toxic insults that lead to phenotypic changes in the animal or plant. These changes more often than not lead to the death or non-survival of the organism, (i.e. a dead end.) But the occasional or rare one that survives, does so because the change is either survival neutral or advantageous. If the latter then the organism may be more successful than its ancestor and even replace or displace that ancestor.

Evolution appears to proceed in a number of steps, some so gradual that they are not apparent except over long periods of time (Darwinian Natural Selection), and some occur rather radically in a relatively brief time of thousands or hundreds of thousand years, which is brief in geological time (Punctuated Equilibrium.) Some of the natural selection may be animal generated (sexual selection of certain male or female characteristics.)

Those who study the evidence conclude that Evolution is as much of a fact as gravity, electromagnetism, weak and strong subatomic forces, the spherical Earth, the Heliocentric Solar System, the Universe composed of galaxies containing billions of stars, grouped clusters of galaxies, super clusters of clusters of galaxies, light (visible) matter and dark (invisible) matter, and a universe estimated at 12-16 billion years old.

The Theory is not evolution, but natural selection. A theory is a scientific, evidence based explanation of a phenomenon. Why do Christian and Islamic Fundamentalists reject the every fact of evolution? I think it is because they do not understand the evidence or do not wish to understand the evidence because it contradicts their need to believe that everything today was as it was when it was created by a magical act of conjuring with words, by a God or Gods.

So Evolution, accepted as fact by scientists, unbelievers, and liberal Christians (Theistic Evolution.)  Believers in Magical Creation by God are fighting evolution in the United States.

What is the evidence proving Evolution?  What is the evidence proving Magical Creation?

The most obvious evidence for evolution is that rock solid evidence that one can see, feel, compare, and date.  That is fossil evidence. We know for a fact that there are fossils. We further know that the fossils of animals and plants are different at successive periods of geological history. We know that the more primitive fossils are found in the oldest sedimentary layers. We know that some fossils show successive gradual changes in successively younger sediments.  We know that hundreds of thousands of animals have ceased to live after certain points of time (extinction). We know that new forms of animals keep making appearances at thousands of points of time. We can trace individual animals through long sequences of their evolution from more primitive forms (horses, rhinoceroses, whales, and primates including human ones.

There is often a challenge to our dating system. That it is imprecise. True it can vary by thousands of years for carbon, and a million or so with K-Argon. But when we are talking about ages of 70 million or 240 million years (a 5 million year two standard deviation) is rather trivial. Some claim that isotope delay is variable, but this is unsupported by any evidence. We can test isotope dating, by other crossed evidence.

We know for a fact that there are tectonic plates making up the Earth’s Crust. These plates are propelled by upwelling and down welling currents in the hot magma of the Earth’s mantle. The result is that the plates drift slowly as the up welling at a rift zone pushes the left and right edges of two plates apart at about 2 cm per year. We know that this rate is constant for two reasons. The continental drift has been measured by satellite laser measurements for about 20 years and has remained consistently at 2 cm per year.

We know that measurements of sediment, a long period type of measurement, average out dry years from wet years, and are remarkably consistent across the oceanic floor. We know that Earths magnetic poles reverse N to S and back to S to N every 10 or 11 thousand years. This causes Ferro-magnetic minerals to line up in those fields while liquid. It cools and the iron containing crystals remain aligned that way. When the field later reverses the newer oceanic plate shows the reversed polarity. Deep drilling of the ocean floor has shown these bands of alternating polarity reversals from the mid-oceanic ridge where they form all the way to the continental edges.

Using these two measurements of tectonic plate and continental drift, we can estimate the age of sediments and igneous rocks at the continental margins. Using both the magnetic field polarity reversals and satellite measurements of 2 cm/yr we can estimate that Cameroon in Africa started separation from the bulge of Brazil 220 million ago in the late Permian Period. (We divide the distance traveled by the velocity of 2 cm/yr.)

Then we use isotope dating of igneous rock on the Brazil coast and the Cameroon coast and get 240-220 million years. By geological timescales this is like hitting bulls eye with a bullet at 600 metres. Thus the accuracy of isotope measurement of fossil ages is supported by collateral evidence of continental drift velocities, ocean floor polarity shift bands, and by a less specific but generally approximate date of sedimentary layering rates. Knowing that we can safely estimate the approximate ages of fossils, and group them phenotypically/anatomically, we can write much of the story of Evolution for the past 500 million years with only minor gaps that are surprisingly few considering the length of the total record.

We know that over vast periods of time millions of animals and plants have appeared and later became extinct in so many separate periods that a single time origin is easily debunked.

Now with the DNA genome projects for humans and several other animals we know new ways to measure evolution as well as explain the mechanisms. DNA mutation rates are relatively predictable and constant for various families of animals. We can use these mutational rates to back date the approximate time that humans and Chimps separated from our common ancestor, 5-7 million years ago. The fossil evidence suggested 8 million years and the debate goes on about the slight difference but to me the closeness is more important than the difference. Chimps and we diverged from a common ancestor sometime between 5-8 million years ago.  The very divergence may have taken a million or more years.

Additionally the Human Genome project has shown us that old genes are not discarded entirely. Some are used at transitional stages of our own human embryology. We, you and I, go through a single cell form (like protozoa), a cell clump form (like slime molds), a blastomere (ball of cells like a living volvox), a two layered phase (like a coelenterate), a primitive chordate with a notochord, a fish like stage with gill slits, to a transitional stage between fish and amphibians (gill slits, tail, and legs), a reptile like stage, primitive mammal, and advanced mammal stages (best observed in the addition of newer evolved brain sections.)  The old parts such as gill slits are recycled into ear bones, labyrinthine and cochlear parts of the ear, and parts of the vocal apparatus. Often a child is born with a residual gill slit (branchial cleft cyst) or even a tail.

In summary the evidence for animal and plant evolution over 2 billion years is supported by fossil evidence, chronological dating cross checked by three other methods, by DNA comparisons of species, and most vividly by human embryology.

FreeAmerican


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"The man who follows is a slave. The man who thinks is free." Robert G. Ingersoll
 


Posts: 42 | Posted: 12:37 AM on April 7, 2003 | IP
FreeAmerican

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I walk along the windy beach
Of  the Moray Firth to teach
My son of the first to dare
Go from the water into the air.

We can almost see them now.
Lobefin fish struggle up somehow
From surf to sand they creep
On fleshy fins they leave the deep.

The fleshy limbs grow one foot each
To walk bravely away from the beach.
They explore a world on sturdy legs.
But in water they must still lay eggs.

Then some lay eggs in hard shell
Protecting their babies quite well
So further inland they can explore
Forests, plains, hills, and more.

Warm little pioneers find a way
To bear live young, no eggs to lay.
Some climb the forest trees where
Predators cannot harm hide or hair.

Fingers that grip also pick,
Sharpen, and use a stick.
This can poke the holes in wood
To catch termites that taste good.

Binocular vision and growing brain
Lead some of them to explore again.
Down from the trees onto the ground
Tasting new foods there to be found.

From the forest some venture out
Onto plains where they will scout.
Running on legs built for speed
They evade the lion hoping to feed.

They can carry their food by one arm
And a club or stone to ward off harm
Is carried firmly in the other hand
To bash or hurl, defending the band.

They explore Earth from sea to land
Exploiting all habitats unable to stand
The drastic changes all taking place;
So they turn their eyes toward outer space.

They now go forward to bravely explore
Moon craters and a Martian shore.
Heroes may die in search for the light
Of knowledge, wisdom, and insight.

Wind over wave crests foaming,
Bring my mind back from roaming
To see a crab scamper up the shore.
Perhaps it too will start to explore.

FreeAmerican
 










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"The man who follows is a slave. The man who thinks is free." Robert G. Ingersoll
 


Posts: 42 | Posted: 01:25 AM on April 7, 2003 | IP
AMD4EVER

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FreeAmerican, I must say, the evidence you provide here is so powerful, it is hard to believe that anyone even tries to debate you (and in the case of this post, they didn't try).  Glad to have you here as you provide a lot of useful and well thought out information!
 


Posts: 11 | Posted: 10:25 AM on June 24, 2003 | IP
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that was a fascinating read to say the least. i think people try to compartmentlize life to much. take colors for example people still think of a color as red or orange when in fact the visable light can't be truly divided into an exacty color scheme. you could never discern a color as totaly red or totally orange. you could narrow it down to an area but the precision would rely on your instramentation which could always be improved apon. Evolution can not be compartmentilized.  
 


Posts: 0 | Posted: 3:21 PM on June 28, 2003 | IP
    
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