Wednesday, September 26, 2012

What Do We Mean by Speciation (Commonly referred to as Micro- and Macro- Evolution)? Part 1 of 2

 
The Macro-Evolutionary Tree of Life

The question often arises amongst Christians whether when speaking of evolution one is referring to microevolution or macroevolution. A question which shows that some Christians are beginning to accept evolution as an explanation within PARTS of the creational process but not necessarily for the ENTIRETY of the creational process. And when used in this self-limiting sense one senses the differences between Christians who are accepting an unmediated process for creation known as young earth creationism (of the 7-Day variety) as versus a mediated process of creationism known as evolutionary creationism of the Darwinian kind - but with the important qualifier that finds G-O-D in it as creation's Creator. And which significantly differs from Darwinian scientific naturalism that finds no God in the process, preferring to rule from a state of neutrality (without partiality to either Christianity or to any other faith, or even to agnosticism, or atheism). Which immediately seems to put both parties on the defensive and not holding any promise for fruitful discussion when voiced in such a fashion.

Why? Because we have fallen into an area of arbitrary philosophical differences that imagines that the Darwinian kind of evolutionary creationism cannot possibly be what the Genesis 1 Story of Creation is explaining. However, in fact, when studying Genesis from the viewpoint of the Ancient Near-Eastern mindset, we soon discover that we can, in fact, claim Darwinian evolution to be an allowed perspective. Especially when finding that our post-Reformational Enlightened claims of literalism cannot be sustained by this venture. And that literalism may only be sustained if we forcefully overlay our doctrinal presuppositions of it over the text itself by disallowing the more proper ANE setting to be historically voiced and heard within its grammatical setting (sic, see the separate sidebars on Genesis, Hermeneutics, Science and the Bible within this website).

Hence the question, "Can we as Christians allow for microevolution, or macroevolution, or both?" To start, we should begin by asking how those two terms are defined within the Christian vernacular (please note that these qualified terms as defined as such have no value scientifically). Thus, while microevolution speaks to the speciation of animals (including man) within their “kinds” or “species”; macroevolution speaks to the entirety of the evolutionary process which includes within it microevolutionary development (thus the hominid line eventuated into today’s homo sapiens species). But, for the non-evolutionary Christian who wishes to believe that God created by an unmediated, spontaneous process, one must conveniently remove apes as the hominids more distant relatives to accept the now modified Christian definition of microevolution. Whereas for the evolutionary Christian this same process of creation resulted through time-and-process beginning with the spark of life (however that resulted) that propagated itself through the sustained directive and administration of our Creator-God's creative design of indeterminacy and randomness.

For a baseline, let us turn to Wikipedia and see what it has to say of the two terms as popularly perceived:

Microevolution
 
Microevolution is the changes in allele frequencies that occur over time within a population.[1] 

*An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome. These DNA codings determine distinct traits that can be passed on from parents to offspring. The process by which alleles are transmitted was discovered by Gregor Mendel and formulated in what is known as Mendel's law of segregation).
 
Allele changes occur due to four different processes: mutation, selection (natural and artificial), gene flow, and genetic drift.
Population genetics is the branch of biology that provides the mathematical structure for the study of the process of microevolution. Ecological genetics concerns itself with observing microevolution in the wild. Typically, observable instances of evolution are examples of microevolution; for example, bacterial strains that have antibiotic resistance.
 
As Contrasted with Macroevolution
 
Microevolution can be contrasted with macroevolution, which is the occurrence of large-scale changes in gene frequencies in a population over a geological time period (i.e. consisting of extended microevolutions). The difference is largely one of approach. Microevolution is reductionist, but macroevolution is holistic.
 
Furthermore, each approach offers different insights into the evolution process. Macroevolution can be seen as the sum of long periods of microevolution, and thus the two are qualitatively identical while being quantitatively different.
 
Lastly, there are four basic processes involved in evolution: Mutation, Selection, Genetic Drift, and Gene  Flow (see the Wiki article for further information). 
 
Origin and Misuse of the term

Origin of the Term

The term microevolution was first used by botanist Robert Greenleaf Leavitt in the journal Botanical Gazette in 1909, addressing what he called the "mystery" of how formlessness gives rise to form.[46]

 
..The production of form from formlessness in the egg-derived individual, the multiplication of parts and the orderly creation of diversity among them, in an actual evolution, of which anyone may ascertain the facts, but of which no one has dissipated the mystery in any significant measure. This microevolution forms an integral part of the grand evolution problem and lies at the base of it, so that we shall have to understand the minor process before we can thoroughly comprehend the more general one...

 
However, Leavitt was using the term to describe what we would now call developmental biology; it was not until Russian Entomologist Yuri Filipchenko used the terms "macroevolution" and "microevolution" in 1927 in his German language work, "Variabilität und Variation", that it attained its modern usage. The term was later brought into the English-speaking world by Theodosius Dobzhansky in his book Genetics and the Origin of Species (1937).[1]
 
Misuse of the Term (See also: Speciation)
 
In young Earth creationism and baraminology a central tenet is that evolution can explain diversity in a limited number of created kinds which can interbreed (which they call "microevolution") while the formation of new "kinds" (which they call "macroevolution") is impossible.[47] [48] This acceptance of "microevolution" only within a "kind" is also typical of old Earth creationism.[49]
 
Scientific organizations such as the American Association for the Advancement of Science describe microevolution as small scale change within species, and macroevolution as the formation of new species, but otherwise not being different from microevolution. In macroevolution, an accumulation of microevolutionary changes leads to speciation.[50] The main difference between the two processes is that one occurs within a few generations, while the other takes place over thousands of years (i.e. a quantitative difference).[51]
 
Essentially they describe the same process; although evolution beyond the species level results in beginning and ending generations which could not interbreed, the intermediate generations could. Even changes in the number of chromosomes can be accounted for by intermediate stages in which a single chromosome divides in generational stages, or multiple chromosomes fuse.
 
A well documented example is the chromosome difference between humans and great apes.[52] Contrary to the claims of some anti-evolution proponents, evolution of life forms beyond the species level ("macroevolution", i.e. speciation) has indeed been observed and documented by scientists on numerous occasions.[53] In creation science, creationists accepted speciation as occurring within a "created kind" or "baramin", but objected to what they called "third level-macroevolution" of a new genus or higher rank in taxonomy. There was ambiguity in their ideas as to where to draw a line on "species", "created kinds", and what events and lineages fall within the rubric of microevolution or macroevolution.[54]  

[End of Wikipedia reference]

Some Conclusions
 
Consequently we quickly discover from the scientific view that:
 
  • Microevolution is a speciation process that occurs within macroevolution.
  • That the one process may occur within a few generations while the other process takes thousands of years or more.
  • That each term essentially describes the same process.
  • That evolution beyond the species level results in beginning and ending generations which cannot be interbred, even though within the immediate generations they can be interbred.
  • And lastly, that both processes have been observed despite the claims of young-earth creationists that they cannot be.
 
At the last, Young-Earth Christians seem to be arguing for a definition of evolution that is limited, and certainly for an understanding of evolution that would not allow the God of Genesis to be involved in the process. Neither as its Originator nor as its Perpetuator. However, for the Evolutionary Creationist, s/he does not see the same, and finds that our Creator-God is not only involved in the process, but continues to be involved in this process even until today. That God's sovereignty is rightly kept in the direction and the execution of this meaningful, purposeful process. Even as His divine will rules over an indeterminant and random process - be it biological, geological, or cosmological. And that even within passages of Scripture we can find hints of this perspective (cf. The Bible and Evolution, Inerrancy, and Other Matters).
 
Below is a link to an additional article which may assist in answering what Evolutionary Creationism is and isn't. And within that article will be additional posts about evolution from a Christian perspective. Added to all of this will be another future article speaking to the Speciation found within evolution itself (Part 2 of this discussion) which will be much more technical than can be attempted here.

Please use these resources as guides to understanding that the God we imagined may not be the real God of our imagination but something even greater than we can imagine. And that rather than being afraid, or combative, with evolutionary formation and biology, we may find, in fact, a greater universe, a greater creation, and a greater Creator, than we had first thought by holding onto outdated, mythic views of instantaneous, spontaneous generation bearing all the earmarks of a primordial earth with layers of primordial history, chemistry, physics and biology. But left neglected and disbelieved when removed by unnecessary theories of Young-Earth Creationism. Unnecessary in that (1) it conflicts with current scientific evidence; (2) it forces its own philosophical perspectives of semi-truths upon creational perspectives; (3) it purposely conflicts with the Genesis Story itself by forcing a literal reading out-of-context to its actual ANE setting; and, (4) imagines full-blown Darwinian evolution to be godless when for the Christian evolutionist it is not (in fact, Darwin himself may have been a Christian regardless of the Scientific Naturalists to have followed in his wake). Consequently, the Evolutionary Creationist will argue for both micro- and macro-evolution, and that without qualification to the scientific theory itself but with the important qualifier of Theism, by which is meant that God has ever been involved in mediation of the process of evolution.
 
R.E. Slater
September 26, 2012

Continue to -
 
What Do We Mean by Speciation
(Commonly referred to as Micro- and Macro- Evolution)?
Part 2 of 2
 

 
 
 

The Bible and Evolution, Inerrancy,
and Other Matters
 

Differences between Evolutionary Creationism
and Darwinian Scientific Naturalism
 



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VISUAL CHARTS & DIAGRAMS
 
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A visual representation of the history of life
on Earth as a geologic spiral
(click to expand)



 
Timeline of Life on Earth
-4500 —
-4000 —
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-1000 —
-500 —
0 —
Formation
of Earth
Atmospheric oxygen
Modern-looking
humans
Axis scale: millions of years ago.
Dates prior to 1000 million years ago are speculative.
 
 
 



* * * * * * * * * * * * * * *

 
Evolutionary Biology
Timeline
  
 
Evolutionary tree showing the divergence of modern species from their common ancestor in the center.[33] The three domains are colored, with bacteria blue, archaea green, and eukaryotes red. 
 

 
* * * * * * * * * * * * * * *


 
The Evolutionary History of Earth 
 
-4500 —
-4000 —
-3500 —
-3000 —
-2500 —
-2000 —
-1500 —
-1000 —
-500 —
0 —
Solar System formed
Impact formed Moon
? Cool surface, oceans, atmosphere
? Earliest evidence of life
Oxygenation of atmosphere
Earliest multicellular organism[19]
 
Earliest known fungi
Earliest known cnidarians
Earliest land invertebrates and plants
Earliest land vertebrates
Earliest known dinosaur
Extinction of non-avian dinosaurs
Scale: Millions of years
 
 
 
Evolution Defined
 
Evolution is the change in the inherited characteristics of biological populations over successive generations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.[1]
 
Life on Earth originated and then evolved from a universal common ancestor approximately 3.7 billion years ago. Repeated speciation and the divergence of life can be inferred from shared sets of biochemical and morphological traits, or by shared DNA sequences. These homologous traits and sequences are more similar among species that share a more recent common ancestor, and can be used to reconstruct evolutionary histories, using both existing species and the fossil record. Existing patterns of biodiversity have been shaped both by speciation and by extinction.[2]
 
Charles Darwin was the first to formulate a scientific argument for the theory of evolution by means of natural selection. Evolution by natural selection is a process that is inferred from three facts about populations: 1) more offspring are produced than can possibly survive, 2) traits vary among individuals, leading to differential rates of survival and reproduction, and 3) trait differences are heritable.[3] Thus, when members of a population die they are replaced by the progeny of parents that were better adapted to survive and reproduce in the environment in which natural selection took place. This process creates and preserves traits that are seemingly fitted for the functional roles they perform.[4] Natural selection is the only known cause of adaptation, but not the only known cause of evolution. Other, nonadaptive causes of evolution include mutation and genetic drift.[5]
 
In the early 20th century, genetics was integrated with Darwin's theory of evolution by natural selection through the discipline of population genetics. The importance of natural selection as a cause of evolution was accepted into other branches of biology. Moreover, previously held notions about evolution, such as orthogenesis and "progress" became obsolete.[6] Scientists continue to study various aspects of evolution by forming and testing hypotheses, constructing scientific theories, using observational data, and performing experiments in both the field and the laboratory. Biologists agree that descent with modification is one of the most reliably established facts in science.[7] Discoveries in evolutionary biology have made a significant impact not just within the traditional branches of biology, but also in other academic disciplines (e.g., anthropology and psychology) and on society at large.[8][9]