Wednesday, November 01, 2006

Evolution meets reality

The Theory of Evolution doesn’t exist as a counter to the bible or belief in gods.  It is founded upon geology, paleontology, archeology, biology, chemistry, etc.  It exists to provide common-sense, factual explanations of the evidence, as a result of using the principles upon which it stands, based on scientific discoveries made throughout the 17th to 21st Centuries.

In particular, discoveries in geology forced scientist to recognize that Earth is far older than stated by common interpretations of the bible.  These discoveries are summed up in a series of geological principles. Andrew MacRae of TalkOrigins states, “Most of these principles were formally proposed by Nicolaus Steno (Niels Steensen, Danish), in 1669, although some have an even older heritage that extends as far back as the authors of the Bible.  An early summary of them is found in Charles Lyell's Principles of Geology, published in 1830-32, and does not differ greatly from a modern formulation.”

The principles are as follows:

  1. Principle of Superposition - in a vertical sequence of sedimentary or volcanic rocks, a higher rock unit is younger than a lower one. "Down" is older, "up" is younger.  This is more commonly called "Law of Superposition" nowadays.
  2. Principle of Original Horizontality - rock layers were originally deposited close to horizontal.
  3. Principle of Lateral Continuity - A rock unit continues laterally unless there is a structure or change to prevent its extension.
  4. Principle of Cross-cutting Relationships - a structure that cuts another is younger than the structure that is cut.
  5. Law of Included Fragments - a structure that is included in another is older than the including structure.
  6. The principle of "uniformitarianism" - processes operating in the past were constrained by the same "laws of physics" as operate today.  This particular principle is not longer viewed as a necessary factor of modern science, but was important for those who lived in a time when most people considered ancient myths as fact.

In science, a principle (or law) is a description of a phenomenon in a particular situation without considering the cause based on evidence.  Laws are commonly retested just as everything is in science.  If a scientist comes across evidence that seems to contradict a known principle or law, that scientist understands that the principle needs retesting to determine how their new data fits into the overall collection of observations.  For example, the principle of original horizontality basically says that sedimentary layers of rock in the ground must be laid horizontality.  However, many rock formations are made up of sedimentary layers that are nearly vertical.  Is the original horizontality wrong?  No.  The layers where originally laid horizontally. Shifts in the Earth’s crust caused the layers to be moved into a nearly vertical position long after they were laid.  This particular observation was a factor in allowing scientists to eventually discover Plate Tectonics.

What does this have to do with the Theory of Evolution?  Even before radioactive dating, these geological principles forced scientists to realize that the Earth must be at least millions of years old.  Further, fossils of life forms are present in various layers of rock.  The fossil record shows a progressive change in life forms on Earth over time.  There is no period in which every species (particularly plants and animal) exist at the same time.  This led curious minds to ask, what is the process for bringing about new species over time?  Creationism said that all creatures were created in the beginning, but the fossil record shows that species come into existence and died out over different and vast periods of time.

Enter Darwin’s exploration.  He studied modern examples of plants and animals, and understood the fossil record.  His research and publication led to the discoveries of evolution and natural selection.  Why does life change over time?  It evolves.  What is the main driving force of evolution?  It is natural selection.

Darwin didn’t actually create the Theory of Evolution.  A theory cannot be made by one person.  A theory is the working explanation for repeatable observations and predictions in nature that are supported by scientific evidence and verified multiple times by various groups of researchers via peer review processes.  To briefly paraphrase Karl Popper, scientific theories must have testability (ability to test the theory), falsifiability (test if the theory is false), or refutability (test if the theory is refutable).

Evidence collected and verified by this process throughout the 20th Century did nothing but continue to reinforce the Theory of Evolution.  The fossil record became more complete and understanding of genetics improved.  Richard Lenski states, “Using DNA sequences, biologists quantify the genetic similarities and differences among species, in order to determine which species are more closely related to one another and which are more distantly related.  In doing so, biologists use essentially the same evidence and logic used to determine paternity in lawsuits.  The pattern of genetic relatedness between all species indicates a branching tree that implies divergence from a common ancestor.”

In the 21st Century, new discoveries in biology are not only further proving evolution; they are actually using knowledge of evolution to make new discoveries, particularly in areas of battling diseases, as mentioned in the article “Antibiotics in Action” at Pharmaceutical Achievers.  In other words, the Theory of Evolution is practical science benefiting humankind directly.  This puts the Theory of Evolution in the same league as Universal Law of Gravitation, Music Theory, theories within Mathematics, and General Relativity.

So, why is this important?  The key difference between notions based on Creationism such as Intelligent Design and actual theories such as Evolution is in their value to science.  Intelligent Design is the end of knowledge. It cannot be tested. It leads to no further discoveries.  It does not improve our understanding of the world around us.  On the other hand, Theory of Evolution is the beginning of knowledge. It is a model of science being used in practical ways. It also leads to more discoveries with endless possibilities.  The value of Theory of Evolution is that is expands our knowledge.  Just as geology opened the door to discovering Evolution, Theory of Evolution is opening the doors to many other sciences involving biology, biotechnology, infectious diseases, genetics, environmentalism, farming, etc.  It leads to a better understanding of the world around us as a logical result of the many observations we make of that world.

References:
Andrew MacRae
Karl Popper
Richard Lenski
Antibiotics in Action

3 comments:

bobo said...

Is counting rings in a tree for its age #2 or #4?

FCSuper said...

Nothing like finding out how old a tree is like chopping it down to count its rings lol

Tree ring counting was all fine and dandy when its practitioners were trying to support biblical timelines. But of course, when geologists popped on the seen, it kinda fell out of favor. :)

Dar said...

Great post! I'm reading Richard Joyce's " The Evolution of Morality". There seems to be much more research lately on the theory that thought processes/social dynamics are evolutionized along with biological and environmental changes. It's all so fascinating...I'll post about the book when I'm finished.